Progress 10/01/99 to 12/17/03
Outputs
1. What major problem or issue is being resolved and how are you resolving it (summarize project aims and objectives)? How serious is the problem? What does it matter? One of the major constraints to expansion of culture of hybrid striped bass (the most commonly cultured Morone species) is the absence of a year- round supply of fingerlings. The current world demand for fingerlings, which are raised to market size, far exceeds the current capability of fingerling producers. Developing methods to produce healthy bass fry throughout the year is one objective of this research. Because of their small size, bass initially consume rotifers and other tiny zooplankton. Methods to optimize production of rotifers and subsequently larger zooplankton are being developed, as are means of producing fingerlings year-round. Means of mass-producing zooplankton in ponds or indoor tanks on a year around basis and methods of harvesting zooplankton to feed to fish in tanks also are being
developed. Although initially dependent upon live zooplankton, hybrid striped bass quickly adapt to manufactured feeds. Current formulations for hybrid striped bass feeds contain higher amounts of protein and lower amounts of carbohydrate than terrestrial livestock feeds. Typically this protein is from relatively expensive animal or high-protein plant products. There is little information available to feed manufacturers and hybrid striped bass farmers regarding nutrient and energy availability from common foodstuffs. The objective of this nutrition research is to improve the productivity and sustainability of commercial hybrid striped bass culture in the United States by developing cost-effective diets, evaluating alternative feeding scenarios, describing biological mechanisms of dietary energy use, and developing dietary strategies for reducing fat accumulation. Sunshine bass production may also be increased if gender-based growth differences that have been discovered in other
important aquaculture species are present and producers are able to concentrate on culturing the faster-growing sex. Other, less obvious, gender differences such as disease resistance or immunocompetency may also be present. The primordial gonadal tissue of fish is bipotential and can develop into a testes or an ovary. In most species the commitment to one or the other is determined by genetic information. However, in some fish, temperature, social signals, or age can result in a change in the functional sex. The phenotype of most species of fish can be altered by administering sex hormones during early development, regardless of the genetic sex (genotype). There is often a relatively short time period during which hormonal sex reversal is effective. Gender-related differences and sex ratios among hybrid fish are related to the characteristic of the parental strain, and little information is available for hybrid striped bass. Techniques to alter the sex have been developed for
the species mentioned above and can guide research on hybrid striped bass. The objective of this research will be to determine if gender-related differences in growth and other production-related characteristics are present in sunshine bass and if culture practices that take advantage of these differences can be developed. Aquaculture-related activities often result in physiological stress responses by the fish. Handling, crowding, water treatments, extreme temperature, and poor water quality can induce stress. Physiological stress in fresh water fish is characterized by an increase in glucose induced by the hormones cortisol and adrenalin, and a decrease in electrolytes. Techniques that diminish changes in the stress response are associated with increased survival and growth. The objective of this research is to develop better management techniques that reduce stress and increase sunshine bass production. Another major constraint on the expansion of the cultured fish industry is
the increased numbers of fish-eating birds that overwinter at, or near, aquaculture facilities. In particular, double-crested cormorant and American white pelican numbers have significantly increased throughout most of their range, and present day numbers are at historical highs, with a large percentage of the population wintering within aquaculture production regions of the southeastern United States. Other bird species, such as the neotropic cormorant and anhinga, also have expanded northward from the Gulf of Mexico into Arkansas. Aquaculture ponds have provided a continual food source for these birds, especially from late fall to spring. Economic losses due to fish-eating birds are also increasing farm costs and reducing net returns. Since these birds, and other migratory birds, are presently protected by federal laws (e.g., the Migratory Bird Treaty Act 1936, 1972), the fish farmer is limited to nonlethal harassment methods and limited lethal removal methods. Nonlethal
methods for minimizing depredation by fish-eating birds are being developed to protect the warm-water fish farming industry from increased depredation on aquaculture production. There are two broad objectives in our efforts at resolving the bird depredation problem. The first is to develop techniques, or devices, that will nonlethally exclude birds from aquaculture ponds. The second objective is to collect, maintain, and disseminate data about the number of cormorants and other fish-eating birds wintering within the region. This data will assist regulatory agencies (e.g., U.S. Fish and Wildlife Service and state agencies) in policymaking. For example, the USFWS has sought the scientific information we have collected for the creation, future implementation, and assessment of a national management strategy for double-crested cormorants. Our continued efforts in conducting aerial surveys during the past years to count double-crested cormorants, white pelicans, and other fish-eating
birds, as well as our quantifying roost sites within the aquaculture production areas is of significant importance as it relates to the management of many of these birds. Birds that inhabit fish culture ponds are also vectors for several types of parasitic diseases that can greatly affect profits of fish farmers. Trematode infestations in some propagated fish are major disease problems. Most digenetic trematodes pass through bird, snail, and fish hosts. Research is focused toward resolving the digenetic trematode problem in cultured fish by developing management strategies that control the populations of the host snails, the best approach to breaking the complex life cycle of these trematodes. Studies to develop effective chemical control of fishpond snails have been initiated, as have studies of snail prey preference by several fish species, potential biocontrol agents. The spread and impact of digenetic trematodes on cultured fish is determined by examining the intestinal tracts of
14 aquatic bird species that carry fish trematodes. In addition to trematodes, tapeworms are also a threat to the well-being and marketability of cultured fish. These worms can kill fish but present an even more serious problem by affecting the shipment of infected fish across state lines. State regulations often prevent import of fish that carry even light tapeworm infections. Studies to develop methods to diagnose, screen, and treat infected fish have been initiated. The research project is directly related to ARS National Program 106 - Aquaculture. Research studies specifically relate to the following program components: Reproduction and Early Development, by conducting research to develop domesticated brood stock, facilitate out-of-season spawning, determine gender-related growth or survival differences, and to provide a year-round fingerling supply of bass species and to improve production of baitfish fry; Growth, Development and Nutrition, by conducting studies to improve feed
formulation, feeding strategies, and feed delivery systems, and decrease handling stress; and, both Aquaculture Production Systems and Sustainability and Environmental Compatibility of Aquaculture Production Systems by conducting studies to reduce or ameliorate bird depredation on cultivated fish, including development and testing of predator deterrent devices and developing information on the impact of bird depredation on fish farming, and by conducting research to improve the understanding of vectoring of infectious agents through predatory birds, and by studying methods to aid in the detection and control of tapeworms. 2. List the milestones (indicators of progress) from your Project Plan. A new bridging project, 6225-31630-004-00D, Improving the Production Efficiency and Sustainability of Morone Species Culture, was approved in December 2003, and has been submitted to the Office of Scientific Quality Review for peer review as to technical quality and relevance to National Program
106 - Aquaculture. The following project milestones were slated for completion in 2004 and have been incorporated into the new bridging project: 2004: Very little is known about optimum conditions for culture of sunshine bass fingerlings in tanks. The fry initially require rotifers for food, but it is not known what enrichment media for the rotifers will result in the highest growth and survival of the sunshine bass fry. Production of sunshine bass fingerlings will be compared after they are fed rotifers cultured with various types of enrichment media. The results will enable farmers to make informed judgments about what types of enrichment is necessary for the live food required for fingerling culture. The major source of highly unsaturated fats (HUFA) in hybrid striped bass diets is limited and expensive marine oils. Hybrid striped bass require certain HUFA in the diet for normal growth, health, and reproduction. It is not known if the HUFA requirement of hybrid striped bass
changes with the level of fat included in the diet. The influence of dietary fat level on the HUFA requirement of hybrid striped will be determined. These data will allow more accurate formulation of diets and allow the next step of experimentation toward decreasing the amount of marine oils in hybrid striped bass diets and thereby reducing production costs. Carbohydrates comprise the largest percentage of feeds for all farm animals except fish. Leaner fish can be produced and feed costs reduced if dietary carbohydrate use in hybrid striped bass can be improved. The influence of amylose:amylopectin starch ratio on digestion and liver energy metabolism of hybrid striped bass will be determined in growth and radiotracer studies. These studies will indicate the extent to which dietary starch ratio can be used as a strategy to increase carbohydrate use by hybrid striped bass. Validate and use an insulin-like growth factor -I assay to determine the most efficient conditions to promote
growth in hybrid striped bass. This liver-produced hormone has recently been shown to mediate many of the growth-promoting effects of the pituitary-derived growth hormone. Trends in cormorant numbers, movements, and duration of use at roosting sites within catfish-producing regions of southeastern Arkansas will be determined by aerial surveys with a fixed-wing aircraft, in conjunction with color leg bands, GPS satellite and radio-transmitters affixed to double-crested cormorants. This will also provide much needed information regarding the effectiveness of the chosen management plan incorporated to regulate cormorant number within the aquaculture production areas of Arkansas. Remote sensing methods will be tested to determine if fish- eating birds prefer or avoid a certain spectral reflectance at fish ponds. A comparison of the pond shoreline treatments of hydrated lime and copper sulfate in experimental ponds will be made. Trematodes that infect cultured fish but that are
collected from aquatic birds, other fish, and snails will be processed for identification, and carrier hosts of specific trematodes will be determined. A treatment for the Asian tapeworm that infects the intestines of fish will be screened and tested for efficacy. 3. Milestones: A. List the milestones that were scheduled to be addressin FY2004. This project was terminated on 12/17/2003 and the milestones/objectives scheduled to be accomplished in FY04 are reported in the bridging project, 6225-31630-004-00D, Improving the Production Efficiency and Sustainability of Morone Species Culture B. List the milestones that you expect to address over the next 3 years. What do you expect to accomplish, year by year, over the next 3 years under each milestone? This project was replaced by project 6225-31630-004-00D. 4. What were the most significant accomplishments this past year? A. Single most significant accomplishment during FY2004. None. B. Other significant accomplishments. None. C.
Significant activities that support special target populations. None. 5. Describe the major accomplishments over the life of the project, including their predicted or actual impact. Double-crested cormorant and other bird predation on cultured fish is often cited as one of the major economic losses for the aquaculture industry. Using six privately owned catfish production facilities across a large area within southeastern Arkansas, scientists at the HDK- Stuttgart National Aquaculture Research Center evaluated the effectiveness of a low-cost, physical barrier system for deterring fish- eating birds under commercial settings. The technique limited cormorant access to aquaculture ponds by 4 to 10 fold, prevented other fish-eating birds from landing at similar rates to complete exclusion at some farms, and limited the duration cormorants stayed on ponds. This relatively economical, nonlethal method has gained industry support, with at least 10 major catfish farms now employing this
approach to greatly reduce losses of cultured fish by double-crested cormorants and other fish- eating birds. Production of many species of fingerling fish in tanks requires feeding them rotifers or other tiny live food that must be cultured with the use of algae. Scientists at the HKD-Stuttgart National Aquaculture Research Center developed a rotifer culture system that utilizes an automated feeding system to deliver a highly condensed algae paste to feed rotifers. The researchers were able to obtain rotifer densities far in excess of what is expected during traditional rotifer culture. The system uses inexpensive and easily obtainable materials, is straightforward to construct, occupies comparatively little space, is modular and expandable and greatly increases the potential for farmers to be able to culture, on a year-round basis, fingerlings of hybrid striped bass and other fish that require rotifers. Much of the pond culture of fish in the United States takes place in
proximity to row crops that often require the use of aerially applied herbicides having the potential to adversely affect fish in culture ponds by damaging pond organisms and water quality. Scientists at the HKD- Stuttgart National Aquaculture Research Center, in collaboration with Dr. Peter Perschbacher at the University of Arkansas at Pine Bluff, determined the effects of several commonly used rice and cotton herbicides and defoliants at various concentrations on pond water quality, phytoplankton, and zooplankton. Only Diuron used as either an herbicide or as a defoliant caused reductions in zooplankton levels and algae to the extent that dissolved oxygen levels decreased to levels adverse to fish health. This information allows farmers to make informed decisions about the application of Diuron in fields adjacent to fish ponds. Female sunshine bass are larger than males by the time the fish reach the most desirable weight for market, about 2.5 pounds; therefore, the efficiency of
hybrid striped bass culture might be increased if it were possible to raise only female fish. Scientists at the HKD-Stuttgart National Aquaculture Research Center conducted experiments in which fingerling female sunshine bass were fed estrogen-treated feed for 40 days, starting with fingerlings that were either 20 or 83 days old. All- female populations of hybrid striped bass were produced; however, feeding estrogen in the feed decreased feed consumption and growth in young fish. These experiments suggest that other avenues of research must be followed in order to take advantage of the normally faster growth of female sunshine bass. Fish meal is an expensive protein source in fish diets, and world supplies are limited. The feasibility of using poultry by-product meal, blood meal, feather meal and two proprietary poultry by-product blends as fishmeal substitutes were determined in separate digestibility trials at the HKD-Stuttgart National Aquaculture Research Center in collaboration
with a major poultry processor and a fish feed manufacturer. The determined digestibility values for poultry by-product meal, blood meal, and feather meal as well as two proprietary by-product blends indicated that these ingredients have potential as substitutes for fish meal in diets for hybrid striped bass. Resolution of the digestibility values will greatly aid future experimentation by researchers and feed manufacturers alike in efforts to find cost-effective substitutes for fish meal in hybrid striped bass feeds. The quality of protein sources varies such that manufacturers of hybrid striped bass feed can not accurately substitute one protein source for another in any diet formula without accurate values of amino acid availability. Research performed at the HKD-Stuttgart National Aquaculture Research Center, in collaboration with Dr. Delbert Gatlin at Texas A&M University, determined the variation in amino acid availability of several feedstuffs. The information generated extends
the database of potential ingredients for hybrid striped bass feeds. These amino acid availability values will allow feed manufacturers to make accurate ingredient substitutions in diet formulations which will lower the cost of feed, hence production, for the industry. In cooler water, hybrid striped bass farmers often feed energy-dense, albeit more expensive, diets in efforts to reduce losses due to cannibalism from unequal growth, poor water quality from uneaten feed, or disease from lower feed intake. This controversial and scientifically unsubstantiated practice was evaluated in temperature-controlled feeding trials conducted at the HKD-Stuttgart National Aquaculture Research Center in cooperation with a regional feed manufacturer and a hybrid striped bass producer. It was determined that 1) below 68DG F there were no discernable improvements to yield and body composition when feeding a high-energy vs. standard diet; 2) above 68DG F there were differences in yield and composition
attributable to the energy density of the diet; and, 3) the lower limit of feeding for hybrid striped bass appears to be around 46-50DG F. Hence, hybrid striped bass farmers over-wintering fish in ponds or stock piling fish in cool-water tanks for year-round production now have objective data upon which to judge the efficacy of feeding a more expensive, energy-dense diet at cooler temperatures. U.S. farmers of hybrid striped bass grow one of two commercial crosses with very little objective information about the advantages or disadvantages of producing either one. In cooperation with a regional hybrid striped bass producer, pond production characteristics (feed consumption, feed conversion rate, growth, and fillet yield) of the two crosses were determined in a head to head comparison at the HKD-Stuttgart National Aquaculture Research Center. Results indicated that fillet yield was 3% greater for sunshine bass (white bass female x striped bass male) than palmetto bass (striped bass
female x white bass male), whereas all other production characteristics were not significantly different. This information suggests to producers that sunshine bass can be more profitable to grow than palmetto bass due to a greater proportion of edible flesh. The secretion of plasma cortisol during fish handling can decrease growth and increase disease susceptibility in fish. Scientists at the HKD-Stuttgart National Aquaculture Research Center used standardized stress tests, several anesthetics, and a wide range of temperatures to determine the conditions under which cortisol levels increase in hybrid striped bass during handling. Metomidate, an anesthetic, suppressed cortisol secretion and temperatures of 50 to 60DG F also suppressed cortisol. The knowledge that hybrid striped bass should be maintained at 50 to 60DG F during transport and handling will greatly reduce economic loss to the industry. Hybrid striped bass produced by mating a female striped bass with a male white bass are
referred to as palmetto bass, while a hybrid produced by crossing female white bass with a male striped bass is referred to as a sunshine bass and has become the preferred hybrid for use in aquaculture. Scientists at the HKD-Stuttgart National Aquaculture Research Center compared the two hybrids with regard to the stress response due to seining activities during three seasons by measuring plasma cortisol, glucose, and chloride concentrations immediately after seining in April, October, and December. Seining the fish in April was more stressful than seining in October and least stressful in December and responses were the same for both hybrids except in December when palmetto bass showed less evidence of stress. These results suggest that, unless farmers mainly harvest their fish during cold weather, response to stress should not enter into their decision on which hybrid to culture. An exotic aquatic snail, Melanoides tuberculata, continues to spread across the US, and it carries a
trematode that causes serious problems in cultured and wild fish species and displaces native mollusks. Experiments were performed by Andrew Mitchell of HKD-Stuttgart National Aquaculture Research Center to determine the temperature limits of the snail. The minimum tolerated temperature was found to be 15DGC and the maximum 35DGC. This information will allow the user to know the geographic limits of the spread of the snail, thereby to know if snail prevention methods are needed in a particular area and if fish stocks (wild or cultured) are in danger of the trematode that can be released from this snail. The toxicity to fish of the copper sulfate pond shoreline snail treatment, developed by scientists at the HKD-Stuttgart National Aquaculture Research Center, at various temperatures was not known, even though the treatment is now regularly used by the commercial fish production industry. The potential fish toxicity of this treatment with and without citric acid was determined at
relevant temperatures. The treatments without citric acid were not toxic at 82DG or 88DGF, while treatments with citric acid were toxic at 88DGF but not at 82DGF. This information will help ensure that pond shoreline copper sulfate treatments are applied without losses to the fish in the production ponds. The successional sequence of zooplankton sizes and types in fry culture ponds was determined, and it was demonstrated that hybrid striped bass fry stocked at the right time during early zooplankton succession had improved survival from the previous average of 10% to 60%. Use of the techniques described in this research will enhance hybrid striped bass fingerling production. Fish farmers using the technique are now averaging 30-40% survival of fry over the entire spawning season. Tank culture of hybrid striped bass fry by feeding them freshwater rotifers that were also cultured in indoor vessels was accomplished for the first time. The fry were then switched to commercially available
feeds and harvested as fingerlings. This technique has the potential to allow year-round production of bass because fry will be more available on a year-round basis. Predictive equations were developed that allow farmers to estimate how long it takes to develop a rotifer bloom in fry culture ponds based upon prevailing or normal spring air or water temperatures. Rotifers are tiny zooplankton that are required by bass for early-life survival and are only present in sufficient quantities for very short times. These equations provide farmers with the only currently available estimate of when to stock fry into ponds during the changing weather conditions of spring, and will enable them to increase fry survival by stocking at the right time. Striped bass fingerling producers rely on fertilizers to develop rotifer and other zooplankton populations required for the survival of their fish, but heavy use of fertilizers deteriorates water quality. Producers may use aeration to alleviate
some types of water quality problems. Research conducted to compare the effect of several aeration techniques on zooplankton development and water quality found that constant aeration with paddlewheel aerators resulted in highest zooplankton crops and moderate water quality deterioration. This technique will enhance the potential to use ponds to crop live feeds for sunshine bass and other fish fingerling production. For the first time hybrid striped bass fry were cultured in tanks by feeding them zooplankton harvested from ponds with a drum filter. It was also demonstrated that equations developed previously relating air and water temperatures to zooplankton succession patterns accurately predicted when maximum concentrations of rotifers and other small zooplankton would be available for harvest by the drum filter. Cultured rotifers, an important constituent of live feeds for cultured larval fish, are difficult to feed automatically. A cooperative study with the ARS's Aquaculture
Systems Research Unit in Pine Bluff was conducted to study the feasibility of automated feeding systems. The study resulted in the development of equations relating rotifer density in monoculture systems to amount of light transmission at several rotifer densities. This information will lead to the development of controlled, automatic rotifer feeding devices and increase sunshine bass production. Striped bass fingerling producers rely on fertilizers to develop rotifer and other live feeds required for the survival of their fish, but the producers do not know the optimum amounts of fertilizer to use. Equations that relate the amount of organic and inorganic fertilizers to the magnitude of rotifer and other zooplankton standing crops and to the ultimate production of sunshine bass fingerlings were developed. These equations will help sunshine bass fingerling producers to economically use fertilizers during pond culture of their fish. Little is known about tank culture of sunshine bass
fry to fingerlings, particularly the amount of live food necessary to sustain the fry. Survival and growth of fry was compared under three feeding rates of cultured rotifers and brine shrimp nauplii (live zooplankton). High feeding rates for fish stocked at 75 fry/L resulted in 53% survival, while lower feeding rates had 35% and 22% survival by 28 days post hatch when they were weaned to commercially prepared feed. The techniques used in this experiment resulted in a very significant increase in survival over the 7% survival rate reported by the industry and should facilitate economical indoor culture of sunshine bass year-round. Pond culture of fish is usually done adjacent to row crop agriculture that includes aerial spraying of herbicides, chemicals that potentially have lethal effects on fish. A continuing collaborative study with University of Arkansas at Pine Bluff faculty determined the effects of full strength aerial application rates and several drift rates of herbicides
used on soybeans and rice. The herbicides used on soybeans and/or rice, fomasefen, aciflourfen and glyphosate, bentazon, imazaquin, fluazifop, clethodim, chlorimuron, thiobencarb, quinclorac, halosulfuron, bensulfuron methyl, triclopyr, clomazone, pendamethalin 2,4-D amine, molinate, clomazone, and pendamethalin, did not have an adverse effect on the phytoplankton and zooplankton communities, while propanil-dry flowables and propanil-liquid used on rice inhibited photosynthesis and have the potential to be harmful to sunshine bass and other pond cultured fish. Knowledge that most herbicides, necessary for soybean or rice culture, are safe to use around aquaculture production facilities will assist the diversification of aquaculture in the Mississippi Delta. Little information exists about the research needs of the fledgling hybrid striped bass industry. The HKD Stuttgart National Aquaculture Research Center held a research-needs forum with fish farmers representing 75% of the
nation's hybrid striped bass production on March 7, 2001, to discuss pressing research needs. Genetic improvement and production strategies were identified as the most important areas needing further research. Results of the forum have provided ARS scientists with a potential research plan to address farmer needs. High-carbohydrate feedstuffs are a relatively inexpensive dietary energy source that, unfortunately, most fish do not use well. Carbohydrate use was increased and fat deposition was decreased by manipulating the ratio of highly branched starch (amylopectin) to less branched starch (amylose) in purified diets. An experiment was conducted in cooperation with the University of Arkansas at Pine Bluff to investigate the relationship of starch utilization in hybrid striped bass. Carbohydrate use was increased and fat deposition was decreased by manipulating the ration of highly branched (amylopectin) to less-branched starch (amylose) in hybrid striped bass. Results will lead to
less expensive, commercial diets for hybrid striped bass. One reason fish feeds are expensive is that not enough is known about potential alternative feedstuffs to safely substitute them in existing diet formulations. In-house research and collaborative efforts with Texas A&M University were conducted to determine the availability of nutrients in nineteen common feedstuffs for hybrid striped bass and red drum using diets that were extruded with commercial methods and equipment. Digestibility values for protein, lipid, energy, twenty essential amino acids, and several fatty acids were determined in both species of fish. Results were made available to feed mills and producers that greatly expanded both the choice and accuracy of nutrient values for practical ingredients in hybrid striped bass and red drum diets thus stimulating reduced cost feeds. Mineral deficiencies in fish can cause deformities, reduce growth, increase susceptibility to disease, and cause death, which would mean
economic loss to fish farmers, but excessive mineral content in the diet, particularly phosphorus, can result in water pollution. The digestibility by sunshine bass of rice products (with and without phytate, a natural chemical that renders minerals unavailable to fish) was determined. There were no significant differences in the digestibility of several minerals, including phosphorus, among the tested rice products, which suggests there is no advantage to using low-phytate rice in hybrid striped bass diets. This information will allow more accurate, less expensive diets to be formulated for hybrid striped bass. Increased fish production may result from the use of sex steroids, although the hormones have been shown to be anabolic in some species. Hybrid sunshine bass of about seven weeks of age (5.09 + 1.7 g, mean + SD) were fed 100 mg/kg feed estrogen or methyl testosterone for three weeks at about 8% body weight per day. After 21 days the control fish were heavier than either
hormone-treated groups and the estrogen-treated fish appeared to have a deformed lower jaw. Increased growth may be achieved with the addition of hormones in the correct dose to hybrid striped bass, or may prove to retard growth and produce morphological abnormalities. In hybrid striped bass culture one sex may grow faster than the other and have the potential to increase harvest yields. The effect of gender on size was determined from several laboratory and commercially produced stocks. Preliminary data suggest that female fish are larger than male fish and that there is a higher proportion of males in market size fish. If one sex performs better than the other, efforts can be directed to raise monosex populations of the desired sex. Handling fish induces physiological stress, which can reduce growth, increase susceptibility to disease, and cause mortality. The tolerance of hybrid striped bass to several water additives and to combinations of additives and physical stress was
tested to determine which treatment reduced the stress response. Metomidate was the most effective in reducing cortisol secretion (an indicator of stress), and tricainemethanesulfonate (MS222) with and without sodium chloride was also effective in reducing stress and promoted rapid recovery to prestress conditions. Refinements of water treatments for handling fish will allow a greater density of fish to be transported with greater survival and less stress. Proper management of fish-eating birds requires accurate knowledge of bird numbers at catfish production facilities. Aerial surveys in a fixed wing aircraft were conducted for the fourth and final consecutive year to document double-crested cormorant, American white pelican, and other fish- eating bird numbers within the catfish production regions of southeastern Arkansas. This information documented a that bird numbers and numbers of roost sites are quite constant. This is important information that the USFWS has requested and
requires in order to formulate a national cormorant management plan. In order for the USFWS to initiate the national cormorant management plan, data concerning cormorant movements at fish farms will be required to assess potential problems. The required information has been gathered during the conduct of several studies dealing with the effectiveness of nonlethal fish predation control techniques. We are now able to provide that agency with scientific data quantifying bird activity within aquaculture production sites and surrounding roosting locations The prevalence and pathogenicity of a trematode (Centrocestus formosanus) known to infect the fountain darter, an endangered fish, was determined. This trematode also infects fathead minnows, golden shiners, hybrid striped bass, and channel catfish under experimental conditions. The trematode has been found in twelve of seventeen fish in the Comal River and was first documented in the San Marcos River in the fountain darter. It is
important to document the spread of such a parasite due to its proximity to the major fish culture areas of the south. This information will allow aquaculture extension agents and veterinarians to diagnose this previously unknown fish disease when it begins to appear in commercial culture areas. The antihelminthic Praziquantel was demonstrated to be an effective control agent against the yellow grub in striped bass hybrids at 0.25 ppm. The work with Praziquantel has shown that practical control of this trematode in fish is possible, although registration of this chemical may be very difficult. Research with this and other antihelminth chemical control agents will lead to a means to control this disease. A shoreline pond treatment with copper sulfate was found to effectively eliminate aquatic snails that carry fish parasites. This treatment will be used by the industry since it has a EPA label and will result in increased copper sulfate sales and decreased incidence of trematode-
parasitized fish. We are already aware of the sale of about 200,000 pounds of copper sulfate for use as this treatment and expect it could save the industry several hundred thousand dollars in lost fish inventories due to trematode parasites. We have given information for the treatment recommendation to be included in an extension handout of the Mississippi Extension Service, Stoneville, AR. The red-rimmed melania, Melanoides tuberculata, is an exotic aquatic snail that is spreading across the southern United States and in geothermal waters in several Midwestern and northwestern states, carrying infectious parasites and displacing native mollusks. Experiments were conducted to determine the temperature and exposure times required to kill various sizes of snails. Those less than 23 mm long were killed when dipped into 50oC water for one minute. Findings provide the basis for disinfection procedures for equipment used in infected waters.
Impacts
(N/A)
Publications
- GOODWIN, A.E., LOCHMANN, R.J., TIEMAN, D.M., MITCHELL, A.J. MASSIVE HEPATIC NEROSIS AND NODULAR REGENERATION IN LARGEMOUTH BASS FED DIETS HIGH IN AVAILABLE CARBOHYDRATES. JOURNAL OF THE WORLD AQUACULTURE SOCIETY. 2002. v. 33. p. 466-477.
- MITCHELL, A.J. REPORTS OF FISH KILLS PRIOR TO 1900 IN THE UNITED STATES. FISHERIES. 2003. v. 11. p. 1-11.
- Mitchell, A.J. 2002. The preference of mollusk eating fish for three aquatic snails that vector fish trematodes.. International Aquatic Animal Health Symposium Proceedings. p. 154.
- MITCHELL, A.J., BRANDT, T.M. TEMPERATURE TOLERANCE OF RED-RIMMED MELANIA MELANOIDES TUBERCUATA, (GASTROPODA: PROSOBRANCHIA: THIARIDAE). WORLD AQUACULTURE SOCIETY MEETING. 2003. p.192.
- MITCHELL, A.J., HOBBS, M.S. THE EFFECT OF CITRIC ACID, COPPER SULFATE CONCENTRATION, AND TEMPERATURE ON THE EFFICACY OF THE POND SHORELINE TREATMENT FOR CONTROLLING RAMS-HORN SNAILS AND THE POTENTIAL TOXICITY OF THIS TREATMENT TO CHANNEL CATFISH.. CATFISH FARMERS OF AMERICA ANNUAL MEETING. 2003. p.15.
- MITCHELL, A.J., BRANDT, T.M. THERMAL LIMITS OF RED-RIMMED MELANIA MELANOIDES TUBERCUATA, (GASTROPODA: PROSOBRANCHIA: THIARIDAE): IMPLICATIONS FOR CONTROL AND DISTRIBUTION OF A SNAIL THAT VECTORS A GILL TREMATODE CAUSING SERIOUS INFECTIONS IN FISH. ANNUAL EASTERN FISH HEALTH WORKSHOP. 2003. p.52.
- MITCHELL, A.J., HOBBS, M.S. FURTHER STUDIES ON THE COPPER SULFATE-CITRIC ACID POND SHORELINE TREATMENT TO CONTROL THE RAMS-HORN SNAIL PLANORBELLA TRIVOLVUS. AMERICAN FISHERY SOCIETY (FISH HEALTH SECTION) PROCEEDINGS. 2003. p.12.
- RADOMSKI, A.A., COLLINS, C.M., FREEMAN, D.W. BUILDING A BETTER MOUSE TRAP: MINIMIZING DOUBLE-CRESTED CORMORANTS PHALACROCORAX AURITUS FROM LANDING ON AQUACULTURE PONDS VIA AN EFFECTIVE NONLETHAL METHOD. EASTERN WILDLIFE DAMAGE MANAGEMENT CONFERENCE PROCEEDINGS. 2003. p. 7.
- RADOMSKI, A.A., FREEMAN, D.W. THE IMPORTANCE OF MONITORING DOUBLE-CRESTED CORMORANTS DUE TO THEIR FUTURE MANAGEMENT PLAN. WATERBIRD SOCIETY. 2002. p. 5.
- RADOMSKI, A.A., COLLINS, C.M., FREEMAN, D.W. AN EFFECTIVE NONLETHAL METHOD TO MINIMIZE DOUBLE-CRESTED CORMORANTS FROM LETTING ON AQUACULTURE PONDS. WATERBIRD SOCIETY. 2002. p. 5.
- LUDWIG, G.M., PERSHBACHER, P., THOMFORDE, H. POTENTIAL EFFECTS OF DIURON DRIFT AS AN AERIALLY-APPLIED COTTON HERBICIDE ON FISH POND PLANKTON AND WATER QUALITY. WORLD AQUACULTURE SOCIETY MEETING. 2003. p. 160.
- LUDWIG, G.M. TANK CULTURE OF SUNSHINE BASS MORONE CHRYSOPS X M SAXATILIS FINGERLINGS WITH THREE CONCENTRATIONS OF ROTIFERS AND ARTEMIA NAUPLII. BOOK OF ABSTRACTS WORLD AQUACULTURE SOCIETY. 2003. p. 160.
- RADOMSKI, A.A., FREEMAN, D.W. THE IMPORTANCE OF MONITORING DOUBLE-CRESTED CORMORANTS PHALACROCORAX AURITUS WITHIN AQUACULTURE PRODUCTION AREAS. AQUACULTURE AMERICA CONFERENCE. 2003. p. 243.
- RADOMSKI, A.A., COLLINS, C.M., FREEMAN, D.W. AN EFFECTIVE, NONLETHAL, METHOD TO MINIMIZE DOUBLE-CRESTED CORMORANTS PHALACROCORAX AURITUS FROM LANDING ON AQUACULTURE PONDS. AQUACULTURE AMERICA CONFERENCE. 2003. p. 242.
- FENECH, A.S., LOCHMANN, S.E., RADOMSKI, A.A. IS IT NECESSARY TO IDENTIFY DIET ITEMS FROM HARD PARTS TO ACCURATELY CHARACTERIZE CORMORANT DIETS?. SOUTHERN DIVISION AMERICAN FISHERIES SOCIETY ANNUAL MEETING. 2003. p. 6.
- RADOMSKI, A.A. MONITORING DOUBLE-CRESTED CORMORANTS WITHIN THE CATFISH PRODUCTION AREAS OF ARKANSAS: 1999-2003. American Ornithologists' Union Annual Meeting. 2003. p. 16.
- RADOMSKI, A.A., FENECH, A., LOCHMANN, R. DIET ANALYSES OF DOUBLE-CRESTED CORMORANTS AND LARGEMOUTH BASS FROM AN ARKANSAS OXBOW LAKE. American Ornithologists' Union Annual Meeting. 2003. p. 117.
- RAWLES, S.D., LOCHMANN, R. EFFECTS OF AMYLOPECTIN/AMYLOSE STARCH RATIO ON GROWTH, BODY COMPOSITION AND GLYCEMIC RESPONSE OF SUNSHINE BASS MORONE CHRYSOPS E X M. SAXATILIS G. JOURNAL OF THE WORLD AQUACULTURE SOCIETY. 2003. v. 34(3). p. 278-288.
- RADOMSKI, A.A., COLLINS, C.M., FREEMAN, D.W. MINIMIZING CORMORANT DAMAGE. CATFISH FARMERS OF ARKANSAS. 2003. p. 2.
- GAYLORD, T.G., RAWLES, S.D. AMINO ACID AVAILABILITY FROM ANIMAL PRODUCTS, BLENDED PRODUCTS AND PLANT PRODUCTS FOR HYBRID STRIPED BASS (MORONE CHRYSOPS X M. SAXATILIS). AQUACULTURE AMERICA CONFERENCE. 2003. p. 436.
- RAWLES, S.D., GAYLORD, T.G. APPARANT PROTEIN, LIPID, ENERGY AND ORGANIC MATTER DIGESTIBILITY FROM ANIMAL PRODUCTS, BLENDED PRODUCTS AND PLANT PRODUCTS FOR HYBRID STRIPED BASS. AQUACULTURE AMERICA CONFERENCE. 2003. p. 437.
- MITCHELL, A.J. BOTHRIOCEPHALUS. SUGGESTED PROCEDURES FOR THE DETECTION AND IDENTIFICATION OF CERTAIN FIN FISH AND SHELLFISH PATHOGENS. Fish Health Section, AMERICAN FISHERY SOCIETY. Blue Book 5TH EDITION. 2003. v.2. p. xii-1 - xii-7.
- Small, B., Davis, K.B. Validation of a time-resolved fluroimmunoassay for measuring plasma cortisol in channel catfish Ictalurus punctatus. Journal of the World Aquaculture Society. 2002. v. 33. p. 184-187.
- PERSCHBACHER, P., LUDWIG, G.M. EFFECTS OF COMMON AERIALLY-APPLIED RICE HERBICIDES ON THE PLANKTON COMMUNITIES OF AQUACULTURE PONDS. AQUACULTURE. 2002. v. 214. p. 241-246.
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Progress 10/01/02 to 09/30/03
Outputs
1. What major problem or issue is being resolved and how are you resolving it? One of the major constraints to expansion of culture of hybrid striped bass (the most commonly cultured Morone species) is the absence of a year- round supply of fingerlings. The current world demand for fingerlings, which are raised to market size, far exceeds the current capability of fingerling producers. Developing methods to produce healthy bass fry throughout the year is one objective of this research. Because of their small size, bass initially consume rotifers and other tiny zooplankton. Methods to optimize production of rotifers and subsequently larger zooplankton are being developed, as are means of producing fingerlings year-round. Means of mass-producing zooplankton in ponds or indoor tanks on a year around basis and methods of harvesting zooplankton to feed to fish in tanks also are being developed. Although initially dependent upon live zooplankton, hybrid striped bass
quickly adapt to manufactured feeds. Current formulations for hybrid striped bass feeds contain higher amounts of protein and lower amounts of carbohydrate than terrestrial livestock feeds. Typically this protein is from relatively expensive animal or high-protein plant products. There is little information available to feed manufacturers and hybrid striped bass farmers regarding nutrient and energy availability from common foodstuffs. The objective of this nutrition research is to improve the productivity and sustainability of commercial hybrid striped bass culture in the United States by developing cost-effective diets, evaluating alternative feeding scenarios, describing biological mechanisms of dietary energy use, and developing dietary strategies for reducing fat accumulation. Sunshine bass production may also be increased if gender-based growth differences that have been discovered in other important aquaculture species are present and producers are able to concentrate on
culturing the faster growing sex. Other, less obvious, gender differences such as disease resistance or immunocompetency may also be present. The primordial gonadal tissue of fish is bipotential and can develop into a testes or an ovary. In most species the commitment to one or the other is determined by genetic information. However, in some fish, temperature, social signals, or age can result in a change in the functional sex. The phenotype of most species of fish can be altered by administering sex hormones during early development, regardless of the genetic sex (genotype). There is often a relatively short time period during which hormonal sex reversal is effective. Gender-related differences and sex ratios among hybrid fish are related to the characteristic of the parental strain, and little information is available for hybrid striped bass. Techniques to alter the sex have been developed for the species mentioned above and can guide research on hybrid striped bass. The
objective of this research will be to determine if gender-related differences in growth and other production related characteristics are present in sunshine bass and if culture practices that take advantage of these differences can be developed. Aquaculture related activities often result in physiological stress responses by the fish. Handling, crowding, water treatments, extreme temperature, and poor water quality can induce stress. Physiological stress in fresh-water fish is characterized by an increase in glucose induced by the hormones cortisol and adrenalin, and a decrease in electrolytes. Techniques that diminish changes in the stress response are associated with increased survival and growth. The objective of this research is to develop better management techniques that reduce stress and increase sunshine bass production. Another major constraint on the expansion of the cultured fish industry is the increased numbers of fish-eating birds that overwinter at, or near,
aquaculture facilities. In particular, double-crested cormorant and American white pelican numbers have significantly increased throughout most of their range and present day numbers are at historical highs, with a large percentage of the population wintering within aquaculture production regions of the southeastern United States. Other bird species, such as the neotropic cormorant and anhinga, also have expanded northward from the Gulf of Mexico into Arkansas. Aquaculture ponds have provided a continual food source for these birds, especially from late fall to spring. Economic losses due to fish-eating birds are also increasing farm costs and reducing net returns. Since these birds, and other migratory birds, are presently protected by federal laws (e.g., the Migratory Bird Treaty Act 1936, 1972), the fish farmer is limited to nonlethal harassment methods and limited lethal removal methods. Nonlethal methods for minimizing depredation by fish-eating birds are being developed to
protect the warm-water fish farming industry from increased depredation on aquaculture production. There are two broad objectives in our efforts at resolving the bird depredation problem. The first is to develop techniques, or devices, that will non-lethally exclude birds from aquaculture ponds. The second objective is to collect, maintain, and disseminate data about the number of cormorants and other fish-eating birds wintering within the region. This data will assist regulatory agencies (e.g., U.S. Fish and Wildlife Service and state agencies) in policymaking. For example, the USFWS has sought the scientific information we have collected for the creation, future implementation, and assessment of a national management strategy for double-crested cormorants. Our continued efforts in conducting aerial surveys during the past years to count double-crested cormorants, white pelicans, and other fish-eating birds, as well as our quantifying roost sites within the aquaculture production
areas, is of significant importance as it relates to the management of many of these birds. Birds that inhabit fish culture ponds are also vectors for several types of parasitic diseases that can greatly affect profits of fish farmers. Trematode infestations in some propagated fish are major disease problems. Most digenetic trematodes pass through bird, snail, and fish hosts. Research is focused toward resolving the digenetic trematode problem in cultured fish by developing management strategies that control the populations of the host snails, the best approach to breaking the complex life cycle of these trematodes. Studies to develop effective chemical control of fishpond snails have been initiated, as have studies of snail prey preference by several fish species, potential biocontrol agents. The spread and impact of digenetic trematodes on cultured fish is determined by examining the intestinal tracts of 14 aquatic bird species that carry fish trematodes. In addition to trematodes,
tapeworms are also a threat to the well-being and marketability of cultured fish. These worms can kill fish, but present an even more serious problem by affecting the shipment of infected fish across state lines. State regulations often prevent import of fish that carry even light tapeworm infections. Studies to develop methods to diagnose, screen, and treat infected fish have been initiated. 2. How serious is the problem? Why does it matter? Presently over 55% of commercial aquaculture in the United States is devoted to one species: channel catfish. However, striped bass and their hybrids with white bass are rapidly gaining share in the world aquaculture market. This should both diversify U.S. aquaculture production and stabilize the U.S. fish farming industry. Increased hybrid striped bass production also will allow expansion into markets away from the southeastern U.S. Recent surveys estimate that annual Morone sp. production is increasing at a rate of nearly 10% per year.
Increased output of hybrid striped bass fingerlings is necessary to expand the production of market-sized fish. In addition, development of year-round fingerling supply has been identified by the Striped Bass Growers Association as the highest priority facing the industry. Year- round supply also is necessary in order to stabilize price fluctuations related to seasonal supply and demand. Additional sunshine bass production would occur if stress-related mortality during handling were reduced. Another potential way of increasing production is the determination of gender-related growth differences and development of monosex culture practices. Commercial production of hybrid striped bass has reached an annual production of approximately 11 million pounds, with an average market price of approximately $2.50 per pound. To improve market share and compete with other fish in the seafood market, prices must decrease to $2. 00 per pound, thereby opening up another 90 million pounds of
potential demand. Currently feed accounts for 40% of the variable costs. Hence, nutrition research can have a dramatic impact on total aquaculture production costs by reducing feed cost by just 10% through alternative and less expensive feed ingredients and/or improving feed efficiency by just 10% through the refinement of feeds to meet the nutritional requirements of fish. Double-crested cormorant numbers have significantly increased throughout most of their range, and present day numbers are at historic highs, with a large percentage of the population wintering within the aquaculture production regions of the southeastern United States. Winter double- crested cormorant populations in the Delta Region of Mississippi have increased nearly 400% since 1994. Currently, channel catfish production in Arkansas exceeds $56 million, and occupies >34,000 acres of water and 155 operators. Losses to the catfish industry in 1996 due to double- crested cormorant depredations were estimated at
over $13 million. Digenetic trematodes in fish cause serious economic losses to the aquaculture industry. The catfish trematode, Bolbophorus confusus, (a trematode in catfish muscle) is now considered one of the major disease threats in the catfish industry. Thousands of acres of catfish are infected with this trematode in Mississippi, Arkansas, and Louisiana and losses among fingerling catfish are very high. The trematode has also been found on a catfish farm in California, and it severely infects some wild populations of catfish. The yellow grub, Clinostomum complanatum, infects the muscle of catfish, baitfish and Morone species with unsightly grubs, what results in consumer rejection of the product. The gill trematode, Centrocestus formosanus, impacts the health of both cultured and wild fish in Florida, Texas, Mississippi, and Georgia. It also is known to infect bait minnows, Morone species, and catfish under experimental conditions. Losses in sales, deductions in prices paid
at processing plants, and loss of business are the impetus behind investigating control of these parasites. The sales of baitfish and Asian carp are often prevented because of their infestation by an Asian tapeworm Bothriocephalus acheilognathi. This worm is one of the two most regulated parasites infecting fish (warm- or cold-water) raised in the United States. More than 100 lots of fish are inspected for tapeworm presence annually just in the state of Arkansas. Losses of revenue associated with this worm in Arkansas are estimated as high a $500,000. 3. How does it relate to the National Program(s) and National Program Component(s) to which it has been assigned? The research project is directly related to ARS National Program 106 - Aquaculture. Research studies specifically relate to the following program components: Reproduction and Early Development, by conducting research to develop domesticated brood stock, facilitate out-of-season spawning, determine gender-related growth or
survival differences, and to provide a year-round fingerling supply of bass species and to improve production of baitfish fry; Growth, Development and Nutrition, by conducting studies to improve feed formulation, feeding strategies, and feed delivery systems, and decrease handling stress; and, both Aquaculture Production Systems and Sustainability and Environmental Compatibility of Aquaculture Production Systems by conducting studies to reduce or ameliorate bird depredation on cultivated fish, including development and testing of predator deterrent devices and developing information on the impact of bird depredation on fish farming, and by conducting research to improve the understanding of vectoring of infectious agents through predatory birds, and by studying methods to aid in the detection and control of tapeworms. 4. What were the most significant accomplishments this past year? A. Single Most Significant Accomplishments during FY 2003: Double-crested cormorant and other bird
predation on cultured fish is often cited as one of the major economic losses for the aquaculture industry. Using six privately owned catfish production facilities across a large area within southeastern Arkansas, scientists at the HKD Stuttgart National Aquaculture Research Center evaluated the effectiveness of a low-cost, physical barrier system for deterring fish- eating birds under commercial settings. The technique limited cormorant access to aquaculture ponds by 4 to 10 fold, prevented other fish-eating birds from landing at similar rates to complete exclusion at some farms, and limited the duration cormorants stayed on ponds. This relatively economical, nonlethal method has gained industry support with at least 10 major catfish farms now employing this approach to greatly reduce losses of cultured fish by double-crested cormorants and other fish-eating birds. B. Other Significant Accomplishments if any: Production of many species of fingerling fish in tanks requires feeding
them rotifers or other tiny live food that must be cultured with the use of algae. Scientists at the HKD Stuttgart National Aquaculture Research Center developed a rotifer culture system that utilizes an automated feeding system to deliver a highly condensed algae paste to feed rotifers. The researchers were able to obtain rotifer densities far in excess of what is expected during traditional rotifer culture. The system uses inexpensive and easily obtainable materials, is straightforward to construct, occupies comparatively little space, is modular and expandable and greatly increases the potential for farmers to be able to culture, on a year-round basis, fingerlings of hybrid striped bass and other fish that require rotifers. Much of the pond culture of fish in the United States takes place in proximity to cotton culture that often requires the use of aerially applied herbicides having the potential to adversely affect fish in culture ponds by damaging pond organisms and water
quality. Scientists at the HKD Stuttgart National Aquaculture Research Center, in collaboration with Dr. Peter Perschbacher at the University of Arkansas at Pine Bluff, determined the effects of seven commonly used cotton herbicides and defoliants at various concentrations on pond water quality, phytoplankton and zooplankton. Only Diuron used as either an herbicide or as a defoliant caused reductions in zooplankton levels and algae to the extent that dissolved oxygen levels decreased to levels adverse to fish health. This information allows cotton farmers to make informed decisions about the application of Diurona in fields adjacent to fish ponds. Female sunshine bass are larger than males by the time the fish reach the most desirable weight for market, about 2.5 pounds; therefore, the efficiency of hybrid striped bass culture might be increased if it were possible to raise only female fish. Scientists at the HKD Stuttgart National Aquaculture Research Center conducted experiments
in which fingerling female sunshine bass were fed estrogen-treated feed for 40 days, starting with fingerlings that were either 20 or 83 days old. All- female populations of hybrid striped bass were produced; however, feeding estrogen in the feed decreased feed consumption and growth in young fish. These experiments suggest that other avenues of research must be followed in order to take advantage of the normally faster growth of female sunshine bass. Fish meal is an expensive protein source in fish diets and world supplies are limited. The feasibility of using poultry by-product meal, blood meal, feather meal, and two proprietary poultry by-product blends as fishmeal substitutes were determined in separate digestibility trials at the HKD Stuttgart National Aquaculture Research Center in collaboration with a major poultry processor and a fish feed manufacturer. The determined digestibility values for poultry by-product meal, blood meal, and feather meal, as well as two proprietary
by-product blends, indicated that these ingredients have potential as substitutes for fish meal in diets for hybrid striped bass. Resolution of the digestibility values will greatly aid future experimentation by researchers and feed manufacturers alike in efforts to find cost-effective substitutes for fish meal in hybrid striped bass feeds. The quality of protein sources varies such that manufacturers of hybrid striped bass feed can not accurately substitute one protein source for another in any diet formula without accurate values of amino acid availability. Research performed at the HKD Stuttgart National Aquaculture Research Center, in collaboration with Dr. Delbert Gatlin at Texas AM University, determined the variation in amino acid availability of several feedstuffs. The information generated extends the database of potential ingredients for hybrid striped bass feeds. These amino acid availability values will allow feed manufacturers to make accurate ingredient substitutions in
diet formulations which will lower the cost of feed, hence production, for the industry. In cooler water, hybrid striped bass farmers often feed energy-dense, albeit more expensive, diets in efforts to reduce losses due to cannibalism from unequal growth, poor water quality from uneaten feed, or disease from lower feed intake. This controversial and scientifically unsubstantiated practice was evaluated in temperature-controlled feeding trials conducted at the HKD Stuttgart National Aquaculture Research Center in cooperation with a regional feed manufacturer and a hybrid striped bass producer. It was determined that 1) below 68DG F there were no discernable improvements to yield and body composition when feeding a high-energy vs. standard diet; 2) above 68DG F there were differences in yield and composition attributable to the energy density of the diet; and, 3) the lower limit of feeding for hybrid striped bass appears to be around 46-50DG F. Hence, hybrid striped bass farmers
over-wintering fish in ponds or stockpiling fish in cool-water tanks for year-round production now have objective data upon which to judge the efficacy of feeding a more expensive, energy-dense diet at cooler temperatures. U.S. farmers of hybrid striped bass grow one of two commercial crosses with very little objective information about the advantages or disadvantages of producing either one. In cooperation with a regional hybrid striped bass producer, pond production characteristics (feed consumption, feed conversion rate, growth, and fillet yield) of the two crosses were determined in a head-to-head comparison at the HKD Stuttgart National Aquaculture Research Center. Results indicated that fillet yield was 3% greater for sunshine bass (white bass female x striped bass male) than palmetto bass (striped bass female x white bass male), whereas all other production characteristics were not significantly different. This information suggests to producers that sunshine bass can be more
profitable to grow than palmetto bass due to a greater proportion of edible flesh. The secretion of plasma cortisol during fish handling can decrease growth and increase disease susceptibility in fish. Scientists at the HKD Stuttgart National Aquaculture Research Center used standardized stress tests, several anesthetics and a wide range of temperatures to determine the conditions under which cortisol levels increase in hybrid striped bass during handling. Metomidate, an anesthetic, suppressed cortisol secretion, and temperatures of 50 to 60DG F also suppressed cortisol. The knowledge that hybrid striped bass should be maintained at 50 to 60DG F during transport and handling will greatly reduce economic loss to the industry. Hybrid striped bass produced by mating a female striped bass with a male white bass are referred to as palmetto bass, while production of hybrids by crossing female white bass with a male striped bass is referred to as a sunshine bass and has become the preferred
hybrid for use in aquaculture. Scientists at the HKD Stuttgart National Aquaculture Research Center compared the two hybrids with regard to the stress response due to seining activities during three seasons by measuring plasma cortisol, glucose, and chloride concentrations immediately after seining in April, October, and December. Seining the fish in April was more stressful than seining in October and least stressful in December, and responses were the same for both hybrids except in December, when palmetto bass showed less evidence of stress. These results suggest that, unless farmers mainly harvest their fish during cold weather, response to stress should not enter into their decision on which hybrid to culture. An exotic aquatic snail, Melanoides tuberculata, continues to spread across the US, and it carries a trematode that causes serious problems in cultured and wild fish species and displaces native mollusks. Experiments were performed by Andrew Mitchell of HKD Stuttgart
National Aquaculture Research Center to determine the temperature limits of the snail. The minimum tolerated temperature was found to be 15DGC and the maximum 35DGC. This information will allow the user to know the geographic limits of the spread of the snail, thereby to know if snail prevention methods are needed in a particular area and if fish stocks (wild or cultured) are in danger of the trematode that can be released from this snail. The toxicity to fish of the copper sulfate pond shoreline snail treatment, developed by scientists at the HKD Stuttgart National Aquaculture Research Center, at various temperatures was not known, even though the treatment is now regularly used by the commercial fish production industry. The potential fish toxicity of this treatment with and without citric acid was determined at relevant temperatures. The treatments without citric acid were not toxic at 82DG or 88DGF while treatments with citric acid were toxic at 88DGF but not at 82DGF. This
information will help ensure that pond shoreline copper sulfate treatments are applied without losses to the fish in the production ponds. C. Significant accomplishments/activities that support target populations: Accomplishments directly support economic development of people in the Mississippi Delta, a special target population. The economic value of fish production greatly benefits the rural areas of the Delta regions of the southeastern U.S. that are characterized by high unemployment, low income and economic stagnation. Commercial fish farming has a significant impact on the economy of the Delta region of the U.S. and has a potential for growth that far exceeds its present economic importance. While fish farming provides jobs to farm workers, its major impact to rural populations is jobs creation in numerous collateral industries such as aquaculture equipment manufacturing, feed mill operations, processing and transportation. 5. Describe the major accomplishments over the life
of the project, including their predicted or actual impact. The successional sequence of zooplankton sizes and types in fry culture ponds was determined, and it was demonstrated that hybrid striped bass fry stocked at the right time during early zooplankton succession had improved survival from the previous average of 10% to 60%. Use of the techniques described in this research will enhance hybrid striped bass fingerling production. Fish farmers using the technique are now averaging 30-40% survival of fry over the entire spawning season. Tank culture of hybrid striped bass fry by feeding them freshwater rotifers that were also cultured in indoor vessels was accomplished for the first time. The fry were then switched to commercially available feeds and harvested as fingerlings. This technique has the potential to allow year-round production of bass because fry will be more available on a year-round basis. Predictive equations were developed that allow farmers to estimate how long it
takes to develop a rotifer bloom in fry culture ponds based upon prevailing or normal spring air or water temperatures. Rotifers are tiny zooplankton that are required by bass for early-life survival and are only present in sufficient quantities for very short times. These equations provide farmers with the only currently available estimate of when to stock fry into ponds during the changing weather conditions of spring and will enable them to increase fry survival by stocking at the right time. Striped bass fingerling producers rely on fertilizers to develop rotifer and other zooplankton populations required for the survival of their fish, but heavy use of fertilizers deteriorates water quality. Producers may use aeration to alleviate some types of water quality problems. Research conducted to compare the effect of several aeration techniques on zooplankton development and water quality found that constant aeration with paddlewheel aerators resulted in highest zooplankton crops
and moderate water quality deterioration. This technique will enhance the potential to use ponds to crop live feeds for sunshine bass and other fish fingerling production. For the first time hybrid striped bass fry were cultured in tanks by feeding them zooplankton harvested from ponds with a drum filter. It was also demonstrated that equations developed previously relating air and water temperatures to zooplankton succession patterns accurately predicted when maximum concentrations of rotifers and other small zooplankton would be available for harvest by the drum filter. Cultured rotifers, an important constituent of live feeds for cultured larval fish, are difficult to feed automatically. A cooperative study with the ARS's Aquaculture Systems Research Unit in Pine Bluff was conducted to study the feasibility of automated feeding systems. The study resulted in the development of equations relating rotifer density in monoculture systems to amount of light transmission at several
rotifer densities. This information will lead to the development of controlled, automatic rotifer feeding devices, and increase sunshine bass production. Striped bass fingerling producers rely on fertilizers to develop rotifer and other live feeds required for the survival of their fish, but the producers do not know the optimum amounts of fertilizer to use. Equations that relate the amount of organic and inorganic fertilizers to the magnitude of rotifer and other zooplankton standing crops and to the ultimate production of sunshine bass fingerlings were developed. These equations will help sunshine bass fingerling producers to economically use fertilizers during pond culture of their fish. Little is known about tank culture of sunshine bass fry to fingerlings, particularly the amount of live food necessary to sustain the fry. Survival and growth of fry were compared under three feeding rates of cultured rotifers and brine shrimp nauplii (live zooplankton). High feeding rates for
fish stocked at 75 fry/L resulted in 53% survival while lower feeding rates had 35% and 22% survival by 28 days post hatch when they were weaned to commercially prepared feed. The techniques used in this experiment resulted in a very significant increase in survival over the 7% survival rate reported by the industry and should facilitate economical indoor culture of sunshine bass year-round. Pond culture of fish is usually done adjacent to row crop agriculture that includes aerial spraying of herbicides, chemicals that potentially have lethal effects on fish. A continuing collaborative study with University of Arkansas at Pine Bluff faculty determined the effects of full strength aerial application rates and several drift rates of herbicides used on soybeans and rice. The herbicides used on soybeans and/or rice, fomasefen, aciflourfen and glyphosate, bentazon, imazaquin, fluazifop, clethodim, chlorimuron, thiobencarb, quinclorac, halosulfuron, bensulfuron methyl, triclopyr,
clomazone, pendamethalin 2,4-D amine, molinate, clomazone, and pendamethalin did not have an adverse effect on the phytoplankton and zooplankton communities, while propanil-dry flowables and propanil-liquid used on rice inhibited photosynthesis and have the potential to be harmful to sunshine bass and other pond-cultured fish. Knowledge that most herbicides, necessary for soybean or rice culture, are safe to use around aquaculture production facilities will assist the diversification of aquaculture in the Mississippi Delta. Herbicides, applied aerially to control weeds in row crops that are adjacent to aquaculture ponds, are potentially detrimental to fish production. A study done in cooperation with the University of Arkansas at Pine Bluff determined the effect of Diuron, a rice herbicide on plankton and water quality. Amounts of this herbicide at concentrations obtainable from drift during spraying depressed dissolved oxygen levels in ponds sufficiently to harm fish. These results
indicate precautions must be taken to avoid drift to adjacent areas during aerial application of the herbicide. Little information exists about the research needs of the fledgling hybrid striped bass industry. The HKD Stuttgart National Aquaculture Research Center held a research-needs forum with fish farmers representing 75% of the nation's hybrid striped bass production on March 7, 2001, to discuss pressing research needs. Genetic improvement and production strategies were identified as the most important areas needing further research. Results of the forum have provided ARS scientists with a potential research plan to address farmer needs. High-carbohydrate feedstuffs are a relatively inexpensive dietary energy source that, unfortunately, most fish do not use well. Carbohydrate use was increased and fat deposition was decreased by manipulating the ratio of highly branched starch (amylopectin) to less branched starch (amylose) in purified diets. An experiment was conducted in
cooperation with the University of Arkansas at Pine Bluff to investigate the relationship of starch utilization in hybrid striped bass. Carbohydrate use was increased and fat deposition was decreased by manipulating the ration of highly-branched (amylopectin) to less-branched starch (amylose) in hybrid striped bass. Results will lead to less expensive, commercial diets for hybrid striped bass. One reason fish feeds are expensive is that not enough is known about potential alternative feedstuffs to safely substitute them in existing diet formulations. In-house research and collaborative efforts with Texas AM University was conducted to determine the availability of nutrients in 19 common feedstuffs for hybrid striped bass and red drum using diets that were extruded with commercial methods and equipment. Digestibility values for protein, lipid, energy, 20 essential amino acids, and several fatty acids were determined in both species of fish. Results were made available to feed mills
and producers that greatly expanded both the choice and accuracy of nutrient values for practical ingredients in hybrid striped bass and red drum diets thus stimulating reduced cost feeds. Mineral deficiencies in fish can cause deformities, reduce growth, increase susceptibility to disease, and cause death, which would mean economic loss to fish farmers, but excessive mineral content in the diet, particularly phosphorus, can result in water pollution. The digestibility by sunshine bass of rice products (with and without phytate, a natural chemical that renders minerals unavailable to fish) was determined. There were no significant differences in the digestibility of several minerals, including phosphorus, among the tested rice products, which suggests there is no advantage to using low-phytate rice in hybrid striped bass diets. This information will allow more accurate, less expensive diets to be formulated for hybrid striped bass. Increased fish production may result from the use of
sex steroids, although the hormones have been shown to be anabolic in some species. Hybrid sunshine bass of about seven weeks of age (5.09 + 1.7 g, mean + SD) were fed 100 mg/kg feed estrogen or methyl testosterone for three weeks at about 8% body weight per day. After 21 days the control fish were heavier than either hormone-treated groups and the estrogen-treated fish appeared to have a deformed lower jaw. Increased growth may be achieved with the addition of hormones in the correct dose to hybrid striped bass, or may prove to retard growth and produce morphological abnormalities. In hybrid striped bass culture one sex may grow faster than the other and have the potential to increase harvest yields. The effect of gender on size was determined from several laboratory and commercially produced stocks. Preliminary data suggest that female fish are larger than male fish and that there is a higher proportion of males in market size fish. If one sex performs better than the other,
efforts can be directed to raise monosex populations of the desired sex. Handling fish induces physiological stress, which can reduce growth, increase susceptibility to disease, and cause mortality. The tolerance of hybrid striped bass to several water additives and to combinations of additives and physical stress was tested to determine which treatment reduced the stress response. Metomidate was the most effective in reducing cortisol secretion (an indicator of stress) and tricainemethanesulfonate (MS222) with and without sodium chloride were also effective in reducing stress and promoted rapid recovery to prestress conditions. Refinements of water treatments for handling fish will allow a greater density of fish to be transported with greater survival and less stress. Proper management of fish-eating birds requires accurate knowledge of bird numbers at catfish production facilities. Aerial surveys in a fixed wing aircraft were conducted for the fourth and final consecutive year
to document double-crested cormorant, American white pelican, and other fish- eating bird numbers within the catfish production regions of southeastern Arkansas. This information documented a that bird numbers and numbers of roost sites are quite constant. This is important information that the USFWS has requested and requires in order to formulate a national cormorant management plan. In order for the USFWS to initiate the national cormorant management plan, data concerning cormorant movements at fish farms will be required to assess potential problems. The required information has been gathered during the conduct of several studies dealing with the effectiveness of nonlethal fish predation control techniques. We are now able to provide that agency with scientific data quantifying bird activity within aquaculture production sites and surrounding roosting locations The prevalence and pathogenicity of a trematode (Centrocestus formosanus) known to infect the fountain darter, an
endangered fish was determined. This trematode also infects fathead minnows, golden shiners, hybrid striped bass and channel catfish under experimental conditions. The trematode has been found in twelve of seventeen fish in the Comal River and was first documented in the San Marcos River in the fountain darter. It is important to document the spread of such a parasite due to its proximity to the major fish culture areas of the south. This information will allow aquaculture extension agents and veterinarians to diagnose this previously unknown fish disease when it begins to appear in commercial culture areas. The antihelminthic Praziquantel was demonstrated to be an effective control agent against the yellow grub in striped bass hybrids at 0.25 ppm. The work with Praziquantel has shown that practical control of this trematode in fish is possible although registration of this chemical may be very difficult. Research with this and other antihelminth chemical control agents will lead to
a means to control this disease. A shoreline pond treatment with copper sulfate was found to effectively eliminate aquatic snails that carry fish parasites. This treatment will be used by the industry since it has a EPA label and will result in increased copper sulfate sales and decreased incidence of trematode parasitized fish. We are already aware of the sale of about 200,000 pounds of copper sulfate for use as this treatment and expect it could save the industry several hundred thousand dollars in lost fish inventories due to trematode parasites. We have given information for the treatment recommendation to be included in an extension handout of the Mississippi Extension Service, Stoneville, MS. The red-rimmed melania Melanoides tuberculata is an exotic aquatic snail that is spreading across the southern United States and in geothermal waters in several Midwestern and northwestern states, carrying infectious parasites and displacing native mollusks. Experiments were conducted
to determine the temperature and exposure times required to kill various sizes of snails. Those less than 23 mm long were killed when dipped into 50oC water for one minute. Findings provide the basis for disinfection procedures for equipment used in infected waters. 6. What do you expect to accomplish, year by year, over the next 3 years? 2004 Very little is known about optimum conditions for culture of sunshine bass fingerlings in tanks. The fry initially require rotifers for food, but it is not known what enrichment media for the rotifers will result in the highest growth and survival of the sunshine bass fry. Production of sunshine bass fingerlings will be compared after they are fed rotifers cultured with various types of enrichment media. The results will enable farmers to make informed judgments about what types of enrichment is necessary for the live food required for fingerling culture. The major source of highly unsaturated fats (HUFA) in hybrid striped bass diets are
limited and expensive marine oils. Hybrid striped bass require certain HUFA in the diet for normal growth, health, and reproduction. It is not known if the HUFA requirement of hybrid striped bass changes with the level of fat included in the diet. The influence of dietary fat level on the HUFA requirement of hybrid striped will be determined. These data will allow more accurate formulation of diets and allow the next step of experimentation toward decreasing the amount of marine oils in hybrid striped bass diets and thereby reducing production costs. Carbohydrates comprise the largest percentage of feeds for all farm animals except fish. Leaner fish can be produced and feed costs reduced if dietary carbohydrate use in hybrid striped bass can be improved. The influence of amylose:amylopectin starch ratio on digestion and liver energy metabolism of hybrid striped bass will be determined in growth and radiotracer studies. These studies will indicate the extent to which dietary starch
ratio can be used as a strategy to increase carbohydrate use by hybrid striped bass. Validate and use an insulin-like growth factor -I assay to determine the most efficient conditions to promote growth in hybrid striped bass. This liver-produced hormone has recently been shown to mediate many of the growth promoting effects of the pituitary-derived growth hormone. Trends in cormorant numbers, movements, and duration of use at roosting sites within catfish-producing regions of southeastern Arkansas will be determined by aerial surveys with a fixed-wing aircraft, in conjunction with color leg bands, GPS satellite and radio-transmitters affixed to double-crested cormorants. This will also provide much-needed information regarding the effectiveness of the chosen management plan incorporated to regulate cormorant number within the aquaculture production areas of Arkansas. Remote sensing methods will be tested to determine if fish- eating birds prefer or avoid a certain spectral
reflectance at fish ponds. A comparison of the pond shoreline treatments of hydrated lime and copper sulfate in experimental ponds will be made. Trematodes that infect cultured fish but that are collected from aquatic birds, other fish and snails will be processed for identification, and carrier hosts of specific trematodes will be determined. A treatment for the Asian tapeworm that infects the intestines of fish will be screened and tested for efficacy. 2005 Water temperature has a strong effect on growth, and the optimum temperature for fingerling culture of sunshine bass in tanks is not known. A variety of water temperatures will be tested to enable the determination of a relationship between temperature and production of fingerlings. This information will facilitate maximum production of fingerlings during tank culture. The dietary requirements for six essential amino acids by hybrid striped bass have not been determined. Also, published requirements for other essential amino
acids by hybrid striped bass are estimates based on few dietary levels and crude statistical ("broken-line") methods. Nutrient requirements can change with respect to production goals, for example, fast growth vs. lean gain. Non-linear regression models of growth and tissue composition will be used to define the remaining six essential amino acids requirements of hybrid striped bass. These values will allow more accurate and efficient formulation of practical and experimental diets for hybrid striped bass under different production scenarios. Develop conditions, protocols, and water treatments to reduce stress during handing of fish important to aquaculture. Growth, production characteristics, and feed palatability and consumption of hybrid striped bass fed diets with poultry by-product blends as fishmeal substitutes will be determined. Documentation of other emerging fish-eating bird species, as well as continued projects on cormorant depredations at baitfish and catfish production
facilities will be determined. 2006 Growth and survival of fingerlings during tank culture is a function of stocking density. A wide range of stocking densities will be tested to determine a mathematical model of the relationship between fry density and production. This information will enable culturists to factor in this variable to maximize production of fingerlings with tank culture. Fish meal is an expensive protein source in fish diets, and world supplies are limited. Growth, production characteristics, palatability, and consumption of hybrid striped bass diets incorporating animal by- product substitutes will be determined in tanks, ponds, and recirculation systems. Highly unsaturated fats (HUFA) are required in hybrid striped bass diets and are supplied by marine oils. The supply of marine oils is limited and expensive. Growth, production characteristics, palatability, and consumption of hybrid striped bass diets incorporating marine oil substitutes will be determined in
tanks, ponds, and recirculation systems. Candidate strains of white bass and striped bass will be established and subsequently grown, spawned, and screened for a variety of growth, nutritional, and compositional criteria, in order to improve production traits of hybrid striped bass. Genotypic female/phenotypic male (XX males) as brood stock to produce all- female populations for aquaculture will be developed. Additional nonlethal deterrents will be developed for controlling fish- eating birds at aquaculture facilities. 7. What science and/or technologies have been transferred and to whom? When is the science and/or technology likely to become available to the end- user (industry, farmer, other scientists)? What are the constraints, if known, to the adoption and durability of the technology products? Results of research studies and technologies developed were made available to customers and the general public through oral presentations (technical and non technical), poster
presentations at local, state, national and international meetings, and scientific papers. Research findings were presented at national, regional, and state conferences including: Annual meetings of the World Aquaculture Society, American Chapter, Louisville, KY; World Aquaculture Society meeting in Salvador, Brazil; American Fisheries Society, Quebec City, Quebec; Striped Bass Producers Association in Louisville, KY; Southeast Region, American Fisheries Society, Tennessee; Field Ornithologists and Wilson Ornithological Society, Water Bird Society, La Crosse, Wisconsin; Catfish Farmers of Arkansas, Hot Springs, AR; 10th Wildlife Damage Management Conference, Hot Springs, AR. Field Day at the University of Arkansas at Pine Bluff, Annual Eastern Health Workshop, International Aquatic Animal Health Symposium, American Fisheries Society Fish Health Section Meeting. Much of the information concerning bird depredation and population levels and movements has also been transferred to the
U.S. Fish and Wildlife Service to enable them to develop a management plan to lessen the adverse effects of birds on aquaculture crops. 8. List your most important publications in the popular press and presentations to organizations and articles written about your work. (NOTE: This does not replace your peer-reviewed publications listed below). Popular Press Radomski, A., Freeman, D.W., Collins, C. Physical barriers on fish ponds and cormorants - a realistic and real-time approach. The Catfish Journal. Nov. 2002. p. 22. Hardin, B. Keeping small catfish from straying. ARS Southern Plains Research Highlights. 2003. p. 38. Hardin, B. Daily feedings boost catfish production. ARS Southern Plains Research Highlights. 2003. p. 74. Hardin, B. Sunshine bass makes a splash. ARS Southern Plains Research Highlights. 2003. p. 24-25. Anonymous. Lab in the limelight - a study in aquaculture at the HKD- Stuttgart National Aquaculture Research Center. Federal Laboratory Consortium for Technology
Transfer, News Link. p. 1, 4. Core, J. Bird barrier decreases pond plundering by cormorants. ARS News Service Press Release. June 16, 2003. Core, J. Nailing the snail that harbors a fish parasite. Agricultural Research Magazine, Sept. 2002. Presentations Griffin, B.R., Davis, K.B., Schlenk, D. Effects of simulated copper sulfate on susceptibility of channel catfish to Edwardsiella ictaluri challenge. Arkansas Aquaculture. Hot Springs, AR. January, 2003. Ludwig, G.M. Constant, nocturnal or no aeration: effects on water quality and zooplankton in heavily fertilized nursery ponds. University of Arkansas at Pine Bluff Aquaculture Field Day. Pine Bluff, AR. October, 2002. Pfeiffer, T.J., Ludwig, G.M. Small scale system for the mass production of rotifers using microalgae paste. University of Arkansas at Pine Bluff Aquaculture Field Day. Pine Bluff, AR. October, 2002. Radomski, A.A., Collins, C., Freeman, D. The 'who, what, when, where, and why' of counting double-crested cormorants
within aquaculture production areas. University of Arkansas at Pine Bluff Aquaculture Field Day. Pine Bluff, AR. October, 2002. Radomski, A.A., Collins, C., Freeman, D. An effective, nonlethal method to prevent double-crested cormorants from landing on fish ponds. Arkansas Aquaculture. Hot Springs, AR. February, 2003. Freeman, D.W. Research program of the HKD-Stuttgart National Aquaculture Research Center. Arkansas Aquaculture. Hot Springs, AR. February, 2003. Freeman, D.W. A national breeding program for the hybrid striped bass industry. Aquaculture America 2003, Special Session - Striped Bass Growers Association. Louisville, KY. February, 2003. RADOMSKI, A.A., COLLINS, C.M., FREEMAN, D.W. CORMORANT RELIEF METHOD. Langston University Aquaculture Field Day Proceedings. 2003. p.2. Trade Journals. Perschbacher, P., Ludwig, G. Herbicide drift and channel catfish ponds. World Aquaculture Magazine. 2002. v.33(4) p. 24-26. Pfeiffer, T.J., Ludwig, G.M. Trial finds microalga paste
suitable for rotifer nutrition. Global Aquaculture Advocate. 2002 v. 5(4) p. 22-23.
Impacts
(N/A)
Publications
- GOODWIN, A.E., LOCHMANN, R.J., TIEMAN, D.M., MITCHELL, A.J. MASSIVE HEPATIC NEROSIS AND NODULAR REGENERATION IN LARGEMOUTH BASS FED DIETS HIGH IN AVAILABLE CARBOHYDRATES. JOURNAL OF THE WORLD AQUACULTURE SOCIETY. 2002. v. 33. p. 466-477.
- MITCHELL, A.J. REPORTS OF FISH KILLS PRIOR TO 1900 IN THE UNITED STATES. FISHERIES. 2003. v. 11. p. 1-11.
- Mitchell, A.J. 2002. The preference of mollusk eating fish for three aquatic snails that vector fish trematodes.. International Aquatic Animal Health Symposium Proceedings. p. 154.
- MITCHELL, A.J., BRANDT, T.M. TEMPERATURE TOLERANCE OF RED-RIMMED MELANIA MELANOIDES TUBERCUATA, (GASTROPODA: PROSOBRANCHIA: THIARIDAE). WORLD AQUACULTURE SOCIETY MEETING. 2003. p.192.
- MITCHELL, A.J., HOBBS, M.S. THE EFFECT OF CITRIC ACID, COPPER SULFATE CONCENTRATION, AND TEMPERATURE ON THE EFFICACY OF THE POND SHORELINE TREATMENT FOR CONTROLLING RAMS-HORN SNAILS AND THE POTENTIAL TOXICITY OF THIS TREATMENT TO CHANNEL CATFISH.. CATFISH FARMERS OF AMERICA ANNUAL MEETING. 2003. p.15.
- MITCHELL, A.J., BRANDT, T.M. THERMAL LIMITS OF RED-RIMMED MELANIA MELANOIDES TUBERCUATA, (GASTROPODA: PROSOBRANCHIA: THIARIDAE): IMPLICATIONS FOR CONTROL AND DISTRIBUTION OF A SNAIL THAT VECTORS A GILL TREMATODE CAUSING SERIOUS INFECTIONS IN FISH. ANNUAL EASTERN FISH HEALTH WORKSHOP. 2003. p.52.
- MITCHELL, A.J., HOBBS, M.S. FURTHER STUDIES ON THE COPPER SULFATE-CITRIC ACID POND SHORELINE TREATMENT TO CONTROL THE RAMS-HORN SNAIL PLANORBELLA TRIVOLVUS. AMERICAN FISHERY SOCIETY (FISH HEALTH SECTION) PROCEEDINGS. 2003. p.12.
- RADOMSKI, A.A., COLLINS, C.M., FREEMAN, D.W. BUILDING A BETTER MOUSE TRAP: MINIMIZING DOUBLE-CRESTED CORMORANTS PHALACROCORAX AURITUS FROM LANDING ON AQUACULTURE PONDS VIA AN EFFECTIVE NONLETHAL METHOD. EASTERN WILDLIFE DAMAGE MANAGEMENT CONFERENCE PROCEEDINGS. 2003. p. 7.
- RADOMSKI, A.A., FREEMAN, D.W. THE IMPORTANCE OF MONITORING DOUBLE-CRESTED CORMORANTS DUE TO THEIR FUTURE MANAGEMENT PLAN. WATERBIRD SOCIETY. 2002. p. 5.
- RADOMSKI, A.A., COLLINS, C.M., FREEMAN, D.W. AN EFFECTIVE NONLETHAL METHOD TO MINIMIZE DOUBLE-CRESTED CORMORANTS FROM LETTING ON AQUACULTURE PONDS. WATERBIRD SOCIETY. 2002. p. 5.
- RADOMSKI, A.A., FREEMAN, D.W. THE IMPORTANCE OF MONITORING DOUBLE-CRESTED CORMORANTS PHALACROCORAX AURITUS WITHIN AQUACULTURE PRODUCTION AREAS. AQUACULTURE AMERICA CONFERENCE. 2003. p. 243.
- RADOMSKI, A.A., COLLINS, C.M., FREEMAN, D.W. AN EFFECTIVE, NONLETHAL, METHOD TO MINIMIZE DOUBLE-CRESTED CORMORANTS PHALACROCORAX AURITUS FROM LANDING ON AQUACULTURE PONDS. AQUACULTURE AMERICA CONFERENCE. 2003. p. 242.
- FENECH, A.S., LOCHMANN, S.E., RADOMSKI, A.A. IS IT NECESSARY TO IDENTIFY DIET ITEMS FROM HARD PARTS TO ACCURATELY CHARACTERIZE CORMORANT DIETS?. SOUTHERN DIVISION AMERICAN FISHERIES SOCIETY ANNUAL MEETING. 2003. p. 6.
- RADOMSKI, A.A. MONITORING DOUBLE-CRESTED CORMORANTS WITHIN THE CATFISH PRODUCTION AREAS OF ARKANSAS: 1999-2003. American Ornithologists' Union Annual Meeting. 2003. p. 16.
- RADOMSKI, A.A., FENECH, A., LOCHMANN, R. DIET ANALYSES OF DOUBLE-CRESTED CORMORANTS AND LARGEMOUTH BASS FROM AN ARKANSAS OXBOW LAKE. American Ornithologists' Union Annual Meeting. 2003. p. 117.
- RAWLES, S.D., LOCHMANN, R. EFFECTS OF AMYLOPECTIN/AMYLOSE STARCH RATIO ON GROWTH, BODY COMPOSITION AND GLYCEMIC RESPONSE OF SUNSHINE BASS MORONE CHRYSOPS E X M. SAXATILIS G. JOURNAL OF THE WORLD AQUACULTURE SOCIETY. 2003. v. 34(3). p. 278-288.
- RADOMSKI, A.A., COLLINS, C.M., FREEMAN, D.W. MINIMIZING CORMORANT DAMAGE. CATFISH FARMERS OF ARKANSAS. 2003. p. 2.
- GAYLORD, T.G., RAWLES, S.D. AMINO ACID AVAILABILITY FROM ANIMAL PRODUCTS, BLENDED PRODUCTS AND PLANT PRODUCTS FOR HYBRID STRIPED BASS (MORONE CHRYSOPS X M. SAXATILIS). AQUACULTURE AMERICA CONFERENCE. 2003. p. 436.
- RAWLES, S.D., GAYLORD, T.G. APPARANT PROTEIN, LIPID, ENERGY AND ORGANIC MATTER DIGESTIBILITY FROM ANIMAL PRODUCTS, BLENDED PRODUCTS AND PLANT PRODUCTS FOR HYBRID STRIPED BASS. AQUACULTURE AMERICA CONFERENCE. 2003. p. 437.
- MITCHELL, A.J. BOTHRIOCEPHALUS. SUGGESTED PROCEDURES FOR THE DETECTION AND IDENTIFICATION OF CERTAIN FIN FISH AND SHELLFISH PATHOGENS. Fish Health Section, AMERICAN FISHERY SOCIETY. Blue Book 5TH EDITION. 2003. v.2. p. xii-1 - xii-7.
- Small, B., Davis, K.B. Validation of a time-resolved fluroimmunoassay for measuring plasma cortisol in channel catfish Ictalurus punctatus. Journal of the World Aquaculture Society. 2002. v. 33. p. 184-187.
- PERSCHBACHER, P., LUDWIG, G.M. EFFECTS OF COMMON AERIALLY-APPLIED RICE HERBICIDES ON THE PLANKTON COMMUNITIES OF AQUACULTURE PONDS. AQUACULTURE. 2002. v. 214. p. 241-246.
- LUDWIG, G.M., PERSHBACHER, P., THOMFORDE, H. POTENTIAL EFFECTS OF DIURON DRIFT AS AN AERIALLY-APPLIED COTTON HERBICIDE ON FISH POND PLANKTON AND WATER QUALITY. WORLD AQUACULTURE SOCIETY MEETING. 2003. p. 160.
- LUDWIG, G.M. TANK CULTURE OF SUNSHINE BASS MORONE CHRYSOPS X M SAXATILIS FINGERLINGS WITH THREE CONCENTRATIONS OF ROTIFERS AND ARTEMIA NAUPLII. BOOK OF ABSTRACTS WORLD AQUACULTURE SOCIETY. 2003. p. 160.
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Progress 10/01/01 to 09/30/02
Outputs
1. What major problem or issue is being resolved and how are you resolving it? One of the major constraints to expansion of culture of hybrid striped bass (the most commonly cultured Morone species) is the absence of a year- round supply of fingerlings. The current world demand for fingerlings, which are raised to market size, far exceeds the current capability of fingerling producers. Developing methods to produce healthy bass fry throughout the year is the objective of this research. Because of their small size, bass initially consume rotifers and other tiny zooplankton. Methods to optimize production of rotifers and subsequently larger zooplankton are being developed, as are means of producing fingerlings year-round. Means of mass-producing zooplankton in ponds or indoor tanks on a year-round basis and methods of harvesting zooplankton to feed to fish in tanks also are being developed. Although initially dependent upon live zooplankton, hybrid striped bass
quickly adapt to manufactured feeds. Current formulations for hybrid striped bass feeds contain higher amounts of protein and lower amounts of carbohydrate than terrestrial livestock feeds. Typically this protein is from relatively expensive animal or high-protein plant products. There is little information available to feed manufacturers and hybrid striped bass farmers regarding nutrient and energy availability from common foodstuffs. The objective of this nutrition research is to improve the productivity and sustainability of commercial hybrid striped bass culture in the United States by developing cost-effective diets, evaluating alternative feeding scenarios, describing biological mechanisms of dietary energy use, and developing dietary strategies for reducing fat accumulation. Sunshine bass production may also be increased if gender-based growth differences that have been discovered in other important aquaculture species are present and producers are able to concentrate on
culturing the faster growing sex. Other, less obvious gender differences such as disease resistance or immunocompetency may also be present. The primordial gonadal tissue of fish is bipotential and can develop into a testes or an ovary. In most species the commitment to one or the other is determined by genetic information. However, in some fish temperature, social signals, or age can result in a change in the functional sex. The phenotype of most species of fish can be altered by administering sex hormones during early development, regardless of the genetic sex (genotype). There is often a relatively short time period during which hormonal sex reversal is effective. Gender-related differences and sex ratios among hybrid fish are related to the characteristic of the parental strain, and little information is available for hybrid striped bass. Techniques to alter the sex have been developed for the species mentioned above and can guide research on hybrid striped bass. The
objective of this research will be to determine if gender-related differences in growth and other production related characteristics are present in sunshine bass and if culture practices that take advantage of these differences can be developed. Aquaculture-related activities often result in physiological stress responses by the fish. Handling, crowding, water treatments, extreme temperature and poor water quality can induce stress. Physiological stress in fresh water fish is characterized by an increase in glucose induced by the hormones cortisol and adrenalin, and a decrease in electrolytes. Techniques that diminish changes in the stress response are associated with increased survival and growth. The objective of this research is to develop better management techniques that reduce stress and increase sunshine bass production. Another major constraint on the expansion of the cultured fish industry is the increased numbers of fish-eating birds that overwinter at, or near,
aquaculture facilities. In particular, double-crested cormorant and American white pelican numbers have significantly increased throughout most of their range, and present day numbers are at historical highs, with a large percentage of the population wintering within the aquaculture production regions of the southeastern United States. Other bird species, such as the neotropic cormorant and anhinga, also have expanded northward from the Gulf of Mexico into Arkansas. Aquaculture ponds have provided a continual food source for these birds especially from late fall to spring. Economic losses due to fish-eating birds are also increasing farm costs and reducing net returns. Since these birds, and other migratory birds, are presently protected by federal laws (e.g., the Migratory Bird Treaty Act 1936, 1972), the fish farmer is limited to non-lethal harassment methods and limited lethal removal methods. Non- lethal methods for minimizing depredation by fish-eating birds are being
developed to protect the warm water fish farming industry from increased depredation on aquaculture production. There are two broad objectives in our efforts at resolving the bird depredation problem. The first is to develop techniques, or a device, that will non-lethally exclude birds from aquaculture ponds. The second objective is to collect, maintain, and disseminate data about the number of fish-eating birds wintering within the region. This data will assist regulatory agencies (e.g., U.S. Fish and Wildlife Service [USFWS]) in policymaking, for example the creation, implementation, and assessment of a national management strategy for double-crested cormorants. Our cooperative (USDA/APHIS/NWRC) efforts to track movements and determine patterns of depredation include the use of satellite telemetry backpacks attached to cormorants over a four-state area (Alabama, Arkansas, Louisiana, and Mississippi) and aerial surveys. The surveys were conducted for the past 2 years to count
double-crested cormorants, white pelicans, and other fish-eating birds, as well as to document and quantify roost sites within the aquaculture production areas. Birds that inhabit fish culture ponds are also vectors for several types of parasitic diseases that can greatly affect profits of fish farmers. Trematode infestations in some propagated fish are major disease problems. Most digenetic trematodes pass through bird, snail, and fish hosts. Research is focused toward resolving the digenetic trematode problem in cultured fish by developing management strategies that control the populations of the host snails, the best approach to breaking the complex life cycle of these trematodes. Studies to develop effective chemical control of fishpond snails have been initiated, as have studies of snail prey preference by several fish species, potential biocontrol agents. The spread and impact of digenetic trematodes on cultured fish is determined by examining the intestinal tracts of 14
aquatic bird species that carry fish trematodes. 2. How serious is the problem? Why does it matter? Presently over 55% of commercial aquaculture in the United States is devoted to one species: channel catfish. However, striped bass and their hybrids with white bass are rapidly gaining share in the world aquaculture market. This should both diversify U.S. aquaculture production and stabilize the U.S. fish farming industry. Increased hybrid striped bass production also will allow expansion into markets away from the southeastern U.S. Recent surveys estimate that annual Morone sp. production is increasing at a rate of nearly 10% per year. Increased output of hybrid striped bass fingerlings is necessary to expand the production of market-sized fish. In addition, development of year-round fingerling supply has been identified by the Striped Bass Growers Association as the highest priority facing the industry. Year- round supply also is necessary in order to stabilize price
fluctuations related to seasonal supply and demand. Additional sunshine bass production would occur if stress related mortality during handling were reduced. Another potential way of increasing production is the determination of gender-related growth differences and development of monosex culture practices. Commercial producers of hybrid striped bass must economically increase yield and decrease time to market to competitively position their products in the market place. Over 40% of the variable cost of hybrid striped bass farming is attributed to feed. One strategy is to reduce feed costs through least-cost formulation. Research is needed on a variety of alternative ingredients for meeting the nutritional requirements of hybrid striped bass. Double-crested cormorant numbers have significantly increased throughout most of their range, and present day numbers are at historic highs, with a large percentage of the population wintering within the catfish productions regions of the
southeastern United States. Winter double- crested cormorant populations in the Delta Region of Mississippi have increased nearly 400% since 1994. Currently, channel catfish production in Arkansas exceeds $5 million, and occupies >12,342 ha of water and 1, 252 facilities. Losses to the catfish industry in 1996 due to double- crested cormorant depredations were estimated at over $13 million. Digenetic trematodes in fish cause serious economic losses to the aquaculture industry. The catfish trematode, Bolbophorus confusus, (a trematode in catfish muscle) is now considered one of the major disease threats in the catfish industry. Thousands of acres of catfish are infected with this trematode in Mississippi, Arkansas, and Louisiana, and losses among fingerling catfish are very high. The trematode has also been found on a catfish farm in California, and it severely infects some wild populations of catfish. The yellow grub Clinostomum complanatum infects the muscle of catfish,
baitfish, and Morone species with unsightly grubs, which results in consumer rejection of the product. The gill trematode, Centrocestus formosanus, impacts the health of both cultured and wild fish in Florida, Texas, Mississippi, and Georgia. It also is known to infect bait minnows, Morone species, and catfish under experimental conditions. Losses in sales, deductions in prices paid at processing plants, and loss of business are the impetus behind investigating control of these parasites. 3. How does it relate to the national Program(s) and National Program Component(s) to which it has been assigned? The research project is directly related to ARS National Program 106 - Aquaculture. Research studies specifically relate to the following program components: Reproduction and Early Development, by conducting research to develop domesticated brood stock, facilitate out of season spawning, determine gender-related growth or survival differences, and to provide a year-round fingerling
supply of bass species and to improve production of baitfish fry; Growth, Development and Nutrition, by conducting studies to improve feed formulation, feeding strategies, and feed delivery systems, and decrease handling stress; and, both Aquaculture Production Systems and Sustainability and Environmental Compatibility of Aquaculture Production Systems by conducting studies to reduce or ameliorate bird depredation on cultivated fish, including development and testing of predator deterrent devices and developing information on the impact of bird depredation on fish farming, and by conducting research to improve the understanding of vectoring of infectious agents through predatory birds. 4. What was your most significant accomplishment this past year? A. Single Most Significant Accomplishments during FY 2002: Double-crested cormorant predation on cultured fish may cause major economic losses for the aquaculture industry. Using multiple catfish production facilities across a large area
within southeastern Arkansas, studies were conducted at the Harry K. Dupree Stuttgart National Aquaculture Research Center, Stuttgart, AR, to determine the effectiveness of a low-cost, physical barrier system. Overall, the physical barrier significantly limited double-crested cormorant access to aquaculture ponds by 4 to 5 fold, as well as limited the duration cormorants stayed on a pond. This relatively economical and easy-to-set- up apparatus should greatly reduce losses of cultured fish by double- crested cormorants and other fish-eating birds. B. Other Significant Accomplishments if any: Little is known about tank culture of sunshine bass fry to fingerlings, particularly the amount of live food necessary to sustain the fry. At the Harry K. Dupree Stuttgart National Aquaculture Research Center, Stuttgart, AR, survival and growth of fry was compared under three feeding rates of cultured rotifers and brine shrimp nauplii (live zooplankton). High feeding rates for fish stocked at
75 fry/L resulted in 53% survival, while lower feeding rates had 35% and 22% survival by 28 days post hatch when they were weaned to commercially prepared feed. The techniques used in this experiment resulted in a very significant increase in survival over the 7% survival rate reported by the industry and should facilitate economical indoor culture of sunshine bass year- round. Herbicides, applied aerially to control weeds in row crops that are adjacent to aquaculture ponds are potentially detrimental to fish production. A study done at the Harry K. Dupree Stuttgart National Aquaculture Research Center, Stuttgart, AR, in cooperation with the University of Arkansas at Pine Bluff determined the effect of Diuron, a rice herbicide, on plankton and water quality. Amounts of this herbicide at concentrations obtainable from drift during spraying depressed dissolved oxygen levels in ponds sufficiently to harm fish. These results indicate precautions must be taken to avoid drift to adjacent
areas during aerial application of the herbicide. One reason fish feeds are expensive is that not enough is known about potential alternative feedstuffs to safely substitute them in existing diet formulations. In-house research at the Harry K. Dupree Stuttgart National Aquaculture Research Center, Stuttgart, AR, and collaborative efforts with Texas A&M were conducted to determine the availability of nutrients in 19 common feedstuffs for hybrid striped bass and red drum using diets that were extruded with commercial methods and equipment. Digestibility values for protein, lipid, energy, 20 essential amino acids, and several fatty acids were determined in both species of fish. Results were made available to feed mills and producers that greatly expanded both the choice and accuracy of nutrient values for practical ingredients in hybrid striped bass and red drum diets, thus stimulating reduced cost feeds. Mineral deficiencies in fish can cause deformities, reduce growth, increase
susceptibility to disease, and cause death, which would mean economic loss to fish farmers, but excessive mineral content in the diet, particularly phosphorus, can result in water pollution. The digestibility by sunshine bass of rice products (with and without phytate, a natural chemical that renders minerals unavailable to fish) was determined at the Harry K. Dupree Stuttgart National Aquaculture Research Center, Stuttgart, AR. There were no significant differences in the digestibility of several minerals, including phosphorus, among the tested rice products, which suggests there is no advantage to using low-phytate rice in hybrid striped bass diets. This information will allow more accurate, less expensive diets to be formulated for hybrid striped bass. Handling fish induces physiological stress, which can reduce growth, increase susceptibility to disease, and cause mortality. The tolerance of hybrid striped bass to several water additives and to combinations of additives and
physical stress was tested at the Harry K. Dupree Stuttgart National Aquaculture Research Center, Stuttgart, AR, to determine which treatment reduced the stress response. Metomidate was the most effective in reducing cortisol secretion (an indicator of stress), and tricainemethanesulfonate (MS222) with and without sodium chloride was also effective in reducing stress and promoted rapid recovery to pre- stress conditions. Refinements of water treatments for handling fish will allow a greater density of fish to be transported with greater survival and less stress. There is little scientific evidence that double-crested cormorants cause depletions of sport fish in natural ecosystems. At the Harry K. Dupree Stuttgart National Aquaculture Research Center, Stuttgart, AR, a cooperative study with the University of Arkansas at Pine Bluff was completed to determine the impact of double-crested cormorant foraging on fish populations in Lake Chicot, Arkansas. Food analysis of 455 cormorants
confirmed the low predation on sport fish and showed that high numbers of shad and yellow bass (55 and 29%) were eaten, whereas catfish and sunfish, the only sport fish found beyond trace amounts, comprised only 5% and 3% of the diet, respectively. These finding will result in a guidebook on identifying fish otoliths, a description of diagnostic markings on fish consumed by double-crested cormorants, seasonal shifts of their diets, and the overall health of these birds. Double-crested comorants are suspected of acquiring polychlorinated biphenyls (PCBs) by ingesting fish in the Great Lakes and then contaminating other aquatic environments in aquaculture production areas. For the first time in Arkansas, a survey of contamination by this pollutant was conducted at the Harry K. Dupree Stuttgart National Aquaculture Research Center, Stuttgart, AR, by analyzing livers from collected double-crested cormorants by mass spectrometry. No significant amounts of PCBs were detected. Findings
will provide important information regarding the health status of double-crested cormorants that winter in Arkansas. The red-rimmed melania, Melanoides tuberculata, is an exotic aquatic snail that is spreading across the southern United States and in geothermal waters in several Midwestern and northwestern states, carrying infectious parasites and displacing native mollusks. Experiments were conducted at the Harry K. Dupree Stuttgart National Aquaculture Research Center, Stuttgart, AR, to determine the temperature and exposure times required to kill various sizes of snails. Those less than 23 mm long were killed when dipped into 50oC water for one minute. Findings provide the basis for disinfection procedures for equipment used in infected waters. C. Significant accomplishments/activities that support target populations: Accomplishments directly support economic development of people in the Mississippi Delta, a special target population. The economic value of fish production
greatly benefits the rural areas of the Delta regions of the southeastern U.S. that are characterized by high unemployment, low income and economic stagnation. Commercial fish farming has a significant impact on the economy of the Delta region of the U.S. and has a potential for growth that far exceeds its present economic importance. While fish farming provides jobs to farm workers, its major impact to rural populations is jobs creation in numerous collateral industries such as aquaculture equipment manufacturing, feed mill operations, processing and transportation. D. Progress Report Extramural Funding Received The fish nutrition research program received a USDA/IFAFS grant for $103, 445 to work on improving carbohydrate use in hybrid striped bass by manipulating the amylose:amylopectin starch ratio of the diet. 5. Describe your major accomplishments over the life of the project, including their predicted or actual impact? The successional sequence of zooplankton sizes and types in
fry culture ponds was determined and it was demonstrated that hybrid striped bass fry stocked at the right time during early zooplankton succession had improved survival from the previous average of 10% to 60%. Use of the techniques described in this research will enhance hybrid striped bass fingerling production. Fish farmers using the technique are now averaging 30-40% survival of fry over the entire spawning season. Tank culture of hybrid striped bass fry by feeding them freshwater rotifers that were also cultured in indoor vessels was accomplished for the first time. The fry were then switched to commercially available feeds and harvested as fingerlings. This technique has the potential to allow year-round production of bass because fry will be more available on a year-round basis. Predictive equations were developed that allow farmers to estimate how long it takes to develop a rotifer bloom in fry culture ponds based upon prevailing or normal spring air or water temperatures.
Rotifers are tiny zooplankton that are required by bass for early-life survival and are only present in sufficient quantities for very short times. These equations provide farmers with the only currently available estimate of when to stock fry into ponds during the changing weather conditions of spring and will enable them to increase fry survival by stocking at the right time. Striped bass fingerling producers rely on fertilizers to develop rotifer and other zooplankton populations required for the survival of their fish, but heavy use of fertilizers deteriorates water quality. Producers may use aeration to alleviate some types of water quality problems. Research conducted to compare the effect of several aeration techniques on zooplankton development and water quality found that constant aeration with paddlewheel aerators resulted in highest zooplankton crops and moderate water quality deterioration. This technique will enhance the potential to use ponds to crop live feeds for
sunshine bass and other fish fingerling production. For the first time hybrid striped bass fry were cultured in tanks by feeding them zooplankton harvested from ponds with a drum filter. It was also demonstrated that equations developed previously relating air and water temperatures to zooplankton succession patterns accurately predicted when maximum concentrations of rotifers and other small zooplankton would be available for harvest by the drum filter. Cultured rotifers, an important constituent of live feeds for cultured larval fish, are difficult to feed automatically. A cooperative study with the ARS Aquaculture Systems Research Unit in Pine Bluff was conducted to study the feasibility of automated feeding systems. The study resulted in the development of equations relating rotifer density in monoculture systems to amount of light transmission at several rotifer densities. This information will lead to the development of controlled, automatic rotifer feeding devices and to
increased sunshine bass production. Striped bass fingerling producers rely on fertilizers to develop rotifer and other live feeds required for the survival of their fish but the producers do not know the optimum amounts of fertilizer to use. Equations that relate the amount of organic and inorganic fertilizers to the magnitude of rotifer and other zooplankton standing crops and to the ultimate production of sunshine bass fingerlings were developed. These equations will help sunshine bass fingerling producers to economically use fertilizers during pond culture of their fish. Pond culture of fish is usually done adjacent to row crop agriculture that includes aerial spraying of herbicides, chemicals that potentially have lethal effects on fish. A continuing collaborative study with University of Arkansas at Pine Bluff faculty determined the effects of full-strength aerial application rates and several drift rates of herbicides used on soybeans and rice. The herbicides used on soybeans
and/or rice, fomasefen, aciflourfen and glyphosate, bentazon, imazaquin, fluazifop, clethodim, chlorimuron, thiobencarb, quinclorac, halosulfuron, bensulfuron methyl, triclopyr, clomazone, pendamethalin 2,4-D amine, molinate, clomazone, and pendamethalin did not have an adverse effect on the phytoplankton and zooplankton communities, while propanil-dry flowables and propanil-liquid, used on rice, inhibited photosynthesis and have the potential to be harmful to sunshine bass and other pond-cultured fish. Knowledge that most herbicides, necessary for soybean or rice culture, are safe to use around aquaculture production facilities will assist the diversification of aquaculture in the Mississippi Delta. Little information exists about the research needs of the fledgling hybrid striped bass industry. The HKD Stuttgart National Aquaculture Research Center held a research-needs forum with fish farmers representing 75% of the nation's hybrid striped bass production on March 7, 2001, to
discuss pressing research needs. Genetic improvement and production strategies were identified as the most important areas needing further research. Results of the forum have provided ARS scientists with a potential research plan to address farmer needs. High-carbohydrate feedstuffs are a relatively inexpensive dietary energy source that, unfortunately, most fish do not use well. Carbohydrate use was increased and fat deposition was decreased by manipulating the ratio of highly branched starch (amylopectin) to less-branched starch (amylose) in purified diets. An experiment was conducted in cooperation with the University of Arkansas at Pine Bluff to investigate the relationship of starch utilization in hybrid striped bass. Carbohydrate use was increased and fat deposition was decreased by manipulating the ration of highly branched (amylopectin) to less-branched starch (amylose) in hybrid striped bass. Results will lead to less expensive, commercial diets for hybrid striped bass.
Increased fish production may result from the use of sex steroids, although the hormones have been shown to be anabolic in some species. Hybrid sunshine bass of about 7 weeks of age (5.09 + 1.7 g, mean + SD) were fed 100 mg/kg feed estrogen or methyl testosterone for 3 weeks at about 8% body weight per day. After 21 days the control fish were heavier than either hormone-treated groups, and the estrogen-treated fish appeared to have a deformed lower jaw. Increased growth may be achieved with the addition of hormones in the correct dose to hybrid striped bass, or may prove to retard growth and produce morphological abnormalities. In hybrid striped bass culture one sex may grow faster than the other and have the potential to increase harvest yields. The effect of gender on size was determined from several laboratory and commercially produced stocks. Preliminary data suggest that female fish are larger than male fish and that there is a higher proportion of males in market size fish.
If one sex performs better than the other, efforts can be directed to raise monosex populations of the desired sex. The depredation caused by diving ducks, primarily lesser scaup, at baitfish facilities is not well known but is thought to be high. A study of 95 lesser scaup, collected from baitfish facilities in 2001 showed that depredation on baitfish was evident but less than anticipated. This information can be used by baitfish farmers to determine if their efforts to remove scaup from their facilities are justified in terms of cost/benefit analysis, or if additional management of pond sediments needs to be considered. Proper management of fish-eating birds requires accurate knowledge of bird numbers at catfish production facilities. Aerial surveys in a fixed wing aircraft were conducted for three consecutive year to document double-crested cormorant, American white pelican, and other fish-eating bird numbers within the catfish production regions of southeastern Arkansas. A
total of 27, 34, and 72 roost sites were found in 2000, 2001, and 2002, respectively. This information is important to regulating agencies, such as the USFWS, in their efforts to formulate a national cormorant management plan. In order for the USFWS to complete national cormorant management plan, data concerning cormorant movements to, and from, breeding grounds, and whether or not there is a constant turnover in cormorants depredating a particular area within their wintering grounds was needed. In 2001 a two- year study was concluded that involving 25 satellite transmitters on double-crested cormorants at night roosts adjacent to catfish producing areas in four states (Alabama, Arkansas, Louisiana, and Mississippi). The findings indicate the breeding distribution is wider than predicted. Data supplied to USFWS will help determine whether a regional reduction of the cormorant population, widespread reduction, or a combination of the two, would be effective in controlling cormorant
damage to aquaculture producers. The prevalence and pathogenicity of a trematode (Centrocestus formosanus) known to infect the fountain darter, an endangered fish, was determined. This trematode also infects fathead minnows, golden shiners, hybrid striped bass, and channel catfish under experimental conditions. The trematode has been found in 12 of 17 fish in the Comal River and was first documented in the San Marcos River in the fountain darter. It is important to document the spread of such a parasite due to its proximity to the major fish culture areas of the south. This information will allow aquaculture extension agents and veterinarians to diagnose this previously unknown fish disease when it begins to appear in commercial culture areas. The antihelminthic Praziquantel was demonstrated to be an effective control agent against the yellow grub in striped bass hybrids at 0.25 ppm. The work with Praziquantel has shown that practical control of this trematode in fish is possible,
although registration of this chemical may be very difficult. Research with this and other antihelminth chemical control agents will lead to a means to control this disease. A shoreline pond treatment with copper sulfate was found to effectively eliminate aquatic snails that carry fish parasites. This treatment will be used by the industry since it has a EPA label, and will result in increased copper sulfate sales and decreased incidence of trematode parasitized fish. We are already aware of the sale of about 200,000 pounds of copper sulfate for use as this treatment and expect it could save the industry several hundred thousand dollars in lost fish inventories due to trematode parasites. We have given information for the treatment recommendation to be included in an extension handout of the Mississippi Extension Service, Stoneville, MS. 6. What do you expect to accomplish, year by year, over the next 3 years? 2003 Fishmeal is an expensive protein source in fish diets, and world
supplies are limited. The availability of nutrients from two different poultry by- product blends, which have potential as fishmeal substitutes, will be determined in separate trials. A major poultry processor and a fish-feed manufacturer are cooperators in these trials. The determined digestibility values will extend the database of ingredients available for feed manufacturers and allow more accurate and cost-effective substitution of fishmeal in diet formulations. Uneven maintenance of body weight or growth in juvenile hybrid striped bass held at cooler temperatures in either tanks or ponds results in tremendous losses due to cannibalism, disease, or poor water quality from uneaten feed. Moreover, producers sometimes purposely retard growth in batches of juvenile fish by holding them at cooler temperatures in order to guarantee a year-round supply for grow-out. Lower temperature limits of feed intake in hybrid striped bass will be determined. Findings will allow hybrid striped bass
producers to make objective decisions regarding diet composition and feeding rate with respect to water temperature during winter pond production or cold tank storage of juveniles. Sexual dimorphism in hybrid striped bass will be determined from fish samples taken from laboratory stocks and acquired from commercial producers. The fastest growing sex will be identified. The effect on growth of exogenous androgens or estrogens will be determined by feeding hybrid striped bass the steroids mixed in the feed. Trends in cormorant numbers, movements, and duration of use at roosting sites within catfish-producing regions of southeastern Arkansas will be determined by aerial surveys with a fixed-wing aircraft, in conjunction with radio-transmitters and color leg bands affixed to double-crested cormorants. This will also provide much-needed information regarding the effectiveness of the chosen management plan incorporated to regulate cormorant number within the aquaculture production areas
of Arkansas. 2004 The optimum stocking density for sunshine bass fry cultured in tanks and the optimum feeding density of rotifers and brine shrimp will be determined. Results from these experiments will help increase production of tank cultured sunshine bass fingerlings and reduce production costs. Growth, production characteristics, and feed palatability and consumption of hybrid striped bass fed diets with poultry by-product blends as fishmeal substitutes will be determined. The impact of the catfish trematode (Bolbophorus confuses) on wild fish species found along the migratory pathway of the white pelican (a disease vector) will be determined. Documentation of other than cormorant fish-eating bird depredations at baitfish and catfish production facilities will be determined. 2005 Optimum temperatures for culture of sunshine bass fry to fingerlings will be determined, as will the most beneficial types of live food enhancements. The dietary requirement for seven essential amino
acids in hybrid striped bass will be determined. Procedures to produce monosex (all males or all females) populations of hybrid striped bass will be determined. Additional non-lethal deterrents will be developed for controlling fish- eating birds at aquaculture facilities. 7. What technologies have been transferred and to whom? When is the technology likely to become available to the end user (industry, farmer other scientist)? What are the constraints, if known, to the adoption durability of the technology? Results of research studies and technologies developed were made available to customers and the general public through oral presentations (technical and non-technical); poster presentations at local, state, national and international meetings; and scientific papers. Research findings were presented at national, regional, and state conferences, including: Aquaculture America 2002 (World Aquaculture Society, American Chapter), San Diego, CA; annual meetings of the American
Fisheries Society, Baltimore, MD; Southeast Region, American Fisheries Society, Little Rock, AR; Southeastern Association of Fish and Wildlife Agencies Annual Conference, Water Bird/Wilson Societies; Catfish Farmers of Arkansas, Little Rock, AR; Fish Feeds and Nutrition Workshop, Baton Rouge, LA. A meeting with major sunshine bass producers at Aquaculture America 2002 facilitated a discussion regarding the potential for HKDSNARC to conduct research to improve parental genetic stocks for hybrid striped bass. Several articles in the popular press also discussed research findings. Much of the information concerning bird depredation and population levels and movements has also been transferred to the U.S. Fish and Wildlife Service to enable them to develop a management plan to lessen the adverse effects of birds on aquaculture crops. 8. List your most important publications and presentations, and articles written about your work (NOTE: this does not replace your review publications which
are listed below) Presentations Ludwig, G.M. Constant, nocturnal, or no aeration: Effects on zooplankton and water quality and zooplankton in heavily fertilized nursery ponds. Presented at the Arkansas Catfish Association annual meeting. Little Rock, AR, Feb. 14-16, 2002. Ludwig, G.M. Constant, nocturnal, or no aeration: Effects on zooplankton and water quality and zooplankton in heavily fertilized nursery ponds. Presented at the American Fisheries Annual Meeting. Baltimore, MD, August 18-24, 2002. Perschbacher, P., Ludwig, G.M., Stone, N., Thomforde, H., Miller, M., Starkey, R. Effect of rice herbicides on fish culture ponds. Presented at the Arkansas Catfish Farmers annual meeting. Little Rock, AR, Feb. 14-16, 2002. Pfeiffer, T.J., Ludwig, G.M. Small-scale system for mass production of rotifers using algae paste. Presented at the Arkansas Catfish Association annual meeting. Little Rock, AR, Feb. 14-16, 2002. Pfeiffer, T.J., Ludwig, G.M. Small-scale system for mass production of
rotifers using algae paste. Presented at the American Fisheries Annual Meeting. Baltimore, MD, August 18-24, 2002. Radomski, A.A. Fish eating birds at aquaculture facilities: What to do about them? Presented at the Kiwanis Club Meeting, Stuttgart, AR, June 2002. Radomski, A.A., Collins, C., Freeman, D. Bird Depredation research. Presented at Catfish Farmers of Arkansas annual meeting, Little Rock, AR, February 2002. Log No. 126309. Radomski, A.A., Freeman, D., Collins, C. Discouraging cormorants and wading birds. 2002. Presented at the Catfish Farmers of Arkansas annual meeting, Little Rock, AR, February 2002. Trade Journals Radomski, A.A., Freeman, D., Collins, C., Wooten, D., Steward, M. Cormorants-Uncertainty of their future management. The Catfish Channel. 2002. v. 39 p. 2-3. Mitchell, A.J. Update and impact of a trematode that infects cultured channel catfish. The Catfish News. 2002. v. 16. p. 17. Radomski, A.A., Freeman, D., Collins, C., Steward, M.D. Using physical barriers to
minimize double-crested cormorants at aquaculture ponds. Catfish Channel. 2002. v. 40. p. 3-4. Radomski, A.A., Freeman, D., Collins, C., Wooten, D., Steward, M. Cormorants-Uncertainty of their future management. Global Aquaculture Advocate. 2001. v. 4(3). p. 72. Popular Press Freking, K. Plan shifts permit power to let farmers draw bead on gorging cormorants. Arkansas Democrat Gazette. February 12, 2002. Mercer, D. Farmers, birds vie over fish. Arkansas Democrat Gazette. November 11, 2001. AP Wire Services. Senators from Arkansas bid to help farmers fend off birds. Daily Leader. February 12, 2002. Leonard, M. Arkansas bighead carp take flying leap toward Chicago. Arkansas Business. August 5, 2002.
Impacts
(N/A)
Publications
- Lochmann, R., Phillips, H., Dasgupta, S., Gatlin, D., Rawles, S. Stable carbon isotope ratios and standard production data as indices of golden shiner, Notemigonus crysoleucas, performance in pond feeding trials. Journal of Applied Aquaculture. 2001. v. 11. p. 21-34.
- Radomski, A.A., Freeman, D. Population trends of double-crested cormorants within the catfish production areas of Arkansas: 1999-2001. Southern Division American Fisheries Society and Southeastern Fishes Council. 2002. Abstract p. 4.
- Fenech, A., Lochmann, S., Radomski A.A. Diet analysis of double-crested cormorants and largemouth bass in Lake Chicot. Arkansas Game and Fish Commission 2nd Annual Research Symposium. 2001. Abstract p. 11.
- Ludwig, G.M. The effects of increasing organic and inorganic fertilizer on water quality, primary production, zooplankton, and sunshine bass, Morone chrysops X M. saxatilis, fingerling production. Journal of Applied Aquaculture. 2002. v. 12(2). p. 1-29.
- Mitchell, A.J., Salmon, M.J., Huffman, D.G., Goodwin, A.E., Brandt, T.M. Experimental infection of an exotic heterophyid trematode Centrocestus formosanus in four aquaculture fishes. North American Journal of Aquaculture. 2002. v. 12. p.283-289.
- Ludwig, G.M. Sunshine bass fingerling production in ponds-The effect of more organic and inorganic fertilizer. American Fisheries Society. 2001. Abstract p. 192.
- Ludwig, G.M. Constant or nocturnal aeration: Effects on water quality and zooplankton standing crops in heavily fertilized sunshine bass nursery ponds. Aquaculture America 2002. 2002. Abstract p.191.
- Ludwig, G.M. Constant or nocturnal aeration: Effects on water quality and zooplankton standing crops in heavily fertilized sunshine bass nursery ponds. Aquaculture America 2002. 2002. Abstract p. 191.
- Mitchell, D. An exotic, tropical, freshwater snail (Melanoides tuberculata) : Biology, distribution, and control. Aquaculture America 2002. 2002. Abstract p. 221.
- Mitchell, D. Preference of black carp for three aquatic snail species. Aquaculture America 2002. 2002. Abstract p. 220.
- Pfeiffer, T.J., Ludwig, G.M. Turbimetric and numeric methods for estimating the density of a cultured rotifer population. Aquaculture America 2002. 2002. Abstract p. 264.
- Rawles, S.D., Rutger, N.J., Gatlin, III, D.M. Mineral availability in low- phytate and other rice products in extruded diets for sunshine bass Morone chrysops x M. saxatilis. Aquaculture America 2002. 2002. Abstract p. 274.
- Radomski, A.A., Freeman, D. Management techniques to minimize double- crested cormorant and other fish-eating birds at aquaculture facilities. Association of Field Ornithologists/Wilson Society. 2002. Abstract p. 32.
- Radomski, A.A., Freeman, D. Monitoring double-crested cormorants in the catfish production areas of Arkansas: 1999-2002. Association of Field Ornithologists/Wilson Society. 2002. Abstract p. 32-33.
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Progress 10/01/00 to 09/30/01
Outputs
1. What major problem or issue is being resolved and how are you resolving it?
One of the major constraints to expansion of culture of hybrid striped bass (the most commonly cultured Morone species) is the absence of a year-round supply of fingerlings. The current world demand for fingerlings, which are raised to market size, far exceeds the current capability of fingerling producers. Developing methods to produce healthy bass fry throughout the year is the objective of this research. Because of their small size bass initially consume rotifers and other tiny zooplankton. Methods to optimize production of rotifers and subsequently larger zooplankton are being developed, as are means of producing fingerlings year-round. Means of mass-producing zooplankton in ponds or indoor tanks on a year-round basis and methods of harvesting zooplankton to feed to fish in tanks also are being developed. Although initially dependent upon live zooplankton, hybrid striped bass quickly adapt to manufactured feeds. Current formulations for hybrid striped bass feeds contain higher
amounts of protein and lower amounts of carbohydrate than terrestrial livestock feeds. Typically this protein is from relatively expensive animal or high-protein plant products. There is little information available to feed manufacturers and hybrid striped bass farmers regarding nutrient and energy availability from common foodstuffs. The objective of this nutrition research is to improve the productivity and sustainability of commercial hybrid striped bass culture in the United States by developing cost effective diets, evaluating alternative feeding scenarios, describing biological mechanisms of dietary energy use, and developing dietary strategies for reducing fat accumulation. Sunshine bass production may also be increased if gender based growth differences are present and producers are able to concentrate on culturing the faster growing ses. Other, less obvious, gender differences such as disease resistance or immunocompetency may also be present. The primordial gonadal
tissue of fish is bipotential and can develop into a testes or an ovary. In most species the commitment to one or the other is determined by genetic information. However, in some fish, temperature, social signals, or age can result in a change in the functional sex. The phenotype of most species of fish can be altered by administering sex hormones during early development, regardless of the genetic sex (genotype). There is often a relatively short time period during which hormonal sex reversal is effective. Gender-related differences and sex ratios among hybrid fish are related to the characteristic of the parental strain, and little information is available for hybrid striped bass. Techniques to alter the sex have been developed for the species mentioned above and can guide research on hybrid striped bass. The objective of this research will be to determine if gender related differences in growth and other production related characteristics are present in sunshine bass and if
culture practices that take advantage of these differences can be developed. Aquaculture-related activities often result in physiological stress responses by the fish. Handling, crowding, water treatments, extreme temperature, and poor water quality can induce stress. Physiological stress in fresh water fish is characterized by an increase in glucose induced by the hormones cortisol and adrenalin, and a decrease in electrolytes. Techniques that diminish changes in the stress response are associated with increased survival and growth. The objective of this research is to develop better management techniques that reduce stress and increase sunshine bass production. Another major constraint on the expansion of the cultured fish industry is the increased numbers of fish-eating birds that over-winter at, or near, aquaculture facilities. In particular, double-crested cormorant and American white pelican numbers have significantly increased throughout most of their range and present day
numbers are at historical highs with a large percentage of the population wintering within the catfish productions regions of the southeastern United States. Aquaculture ponds have provided a continual food source for these birds especially from late fall to spring. Economic losses due to fish-eating birds are also increasing farm costs and reducing net returns. Since these birds, and other migratory birds, are presently protected by federal laws (e.g., the Migratory Bird Treaty Act 1936, 1972), the fish farmer is limited to non-lethal harassment methods and limited lethal removal methods. Non-lethal methods for minimizing depredation by fish- eating birds are being developed to protect the warm water fish farming industry from increased depredation on aquaculture production. There are two broad objectives in our efforts at resolving the bird depredation problem. The first is to develop techniques, or a device, that will non-lethally exclude birds from fishponds. The second
objective is to collect, maintain, and disseminate data on the fish- eating bird numbers wintering within the region. This data will assist regulatory agencies (e.g., U.S. Fish and Wildlife Service) in policy making, such as the creation and implementation of a national management strategy for double-crested cormorants. Our cooperative (USDA/APHIS/NWRC) efforts to track movements and determine patterns of depredation include the use of satellite telemetry backpacks attached to cormorants over a four-state area (Alabama, Arkansas, Louisiana, and Mississippi) and aerial surveys. The surveys were conducted for the past 2 years to count double-crested cormorant and white pelican numbers, as well as document roost sites within the catfish producing areas. Birds that inhabit fish culture ponds are also vectors for several types of parasitic diseases that can greatly affect profits of fish farmers. Trematode infestations in some propagated fish are major disease problems. Most digenetic
trematodes pass through bird, snail, and fish hosts. Research is focused toward resolving the digenetic trematode problem in cultured fish by developing management strategies that control the populations of the host snails, the best approach to breaking the complex life cycle of these trematodes. Studies to develop effective chemical control of fishpond snails have been initiated as have studies of snail prey preference by several fish species, potential biocontrol agents. The spread and impact of digenetic trematodes on cultured fish is determined by examining the intestinal tracts of 14 aquatic bird species that carry fish trematodes.
2. How serious is the problem? Why does it matter?
Presently over 55% of commercial aquaculture in the United States is devoted to one species: channel catfish. However, striped bass and their hybrids with white bass are rapidly gaining share in the world aquaculture market. This should both diversify U.S. aquaculture production and stabilize the U.S. fish farming industry. Increased hybrid striped bass production also will allow expansion into markets away from the southeastern U.S. Recent surveys estimate that annual Morone sp. production is increasing at a rate of nearly 10% per year. Increased output of hybrid striped bass fingerlings is necessary to expand the production of market-sized fish. In addition, development of year-round fingerling supply has been identified by the Striped Bass Growers Association as the highest priority facing the industry. Year- round supply also is necessary in order to stabilize price fluctuations related to seasonal supply and demand. Additional sunshine bass production would occur if
stress-related mortality during handling were reduced. Another potential way of increasing production is the determination of gender-related growth differences and development of monosex culture practices. Commercial producers of hybrid striped bass must economically increase yield and decrease time to market to competitively position their products in the market place. Over 40% of the variable cost of hybrid striped bass farming is attributed to feed. One strategy is to reduce feed costs through least-cost formulation. Research is needed on a variety of alternative ingredients for meeting the nutritional requirements of hybrid striped bass. Double-crested cormorant numbers have significantly increased throughout most of their range, and present day numbers are at historic highs, with a large percentage of the population wintering within the catfish productions regions of the southeastern United States. Winter double- crested cormorant populations in the Delta Region of Mississippi
have increased nearly 400% since 1994. Currently, channel catfish production in Arkansas exceeds $5 million, and occupies >12,342 ha of water and 1,252 facilities. Losses to the catfish industry in 1996 due to double- crested cormorant depredations were estimated at over $13 million. Digenetic trematodes in fish cause serious economic losses to the aquaculture industry. The catfish trematode, Bolbophorus confusus, (a trematode in catfish muscle) is now considered one of the major disease threats in the catfish industry. Thousands of acres of catfish are infected with this trematode in Mississippi, Arkansas, and Louisiana and losses among fingerling catfish are very high. The trematode has also been found on a catfish farm in California, and it severely infects some wild populations of catfish. The yellow grub Clinostomum complanatum infects the muscle of catfish, baitfish, and Morone species with unsightly grubs, resulting in consumer rejection of the product. The gill trematode,
Centrocestus formosanus, impacts the health of both cultured and wild fish in Florida, Texas, Mississippi, and Georgia. It also is known to infect bait minnows, Morone species, and catfish under experimental conditions. Losses in sales, deductions in prices paid at processing plants, and loss of business are the impetus behind investigating control of these parasites.
3. How does it relate to the National Program(s) and National Component(s)?
The research project is directly related to ARS National Program 106 - Aquaculture. Research studies specifically relate to the following program components: Reproduction and Early Development, by conducting research to develop domesticated broodstock, facilitate out of season spawning, determine gender-related growth or survival differences, and to provide a year-round fingerling supply of bass species and to improve production of baitfish fry; Growth, Development and Nutrition, by conducting studies to improve feed formulation, feeding strategies,and feed delivery systems, and decrease handling stress; and, both Aquaculture Production Systems and Sustainability and Environmental Compatibility of Aquaculture Production Systems, by conducting studies to reduce or ameliorate bird depredation on cultivated fish, including development and testing of predator deterrent devices and developing information on the impact of bird depredation on fish farming, and by conducting research to
improve the understanding of vectoring of infectious agents through predatory birds.
4. What were the most significant accomplishments this past year?
A. Single Most Significant Accomplishments during FY 2001: Double-crested cormorant predation on cultured fish may cause major economic losses for the aquaculture industry. The avoidance effectiveness of a physical barrier, modified to minimize cost, labor, and setup/takedown time and set up at a large-scale catfish production facility in southeastern Arkansas was determined. Overall, the modified physical barrier significantly limited double-crested cormorant access to the ponds. This easy-to-set-up apparatus should greatly reduce losses of cultured fish, to double-crested cormorants. B. Other Significant Accomplishments if any: Striped bass fingerling producers rely on fertilizers to develop rotifer and other zooplankton populations required for the survival of their fish but, heavy use of fertilizers deteriorates water quality. Producers may use aeration to alleviate some types of water quality problems. Research conducted to compare the effect of several aeration techniques on
zooplankton development and water quality found that constant aeration with paddlewheel aerators resulted in highest zooplankton crops and moderate water quality deterioration. This technique will enhance the potential to use ponds to crop live feeds for sunshine bass and other fish fingerling production. Mineral deficiencies in fish can cause deformities, reduce growth, increase susceptibility to disease, and cause death which would mean economic loss to fish farmers, but excessive mineral content in the diet, particularly phosphorus, can result in water pollution. The digestibility of rice products both with and without a natural chemical (phytate) which binds up minerals, making them unavailable to fish, was determined with low-phytate rice developed at the ARS/Dale Bumpers National Rice Research Center (DBNRRC). Phytate concentrations in the rice and test diets were verified; diets were extruded at the Food Protein Center of Texas A&M University (TAMU) in collaboration with Dr.
Delbert Gatlin (TAMU). This study also provides nutrient digestibility values for several rice products that are sorely needed by producers and feed manufacturers to formulate least-cost diets for hybrid striped bass. If one sex demonstrates a growth advantage, techniques will be needed to produce all, or predominately, that sex in order to increase fish production. Four-day-old sunshine bass were treated with an estrogen solution dissolved in ethanol for two and one-half hours and placed in a fertilized pond. These fish were successfully raised in ponds and are being grown out to determine the phenotypic sex. This technique can be expanded to test the sex plasticity of hybrid striped bass when they are very young. Little information exists about the research needs of the fledgling hybrid striped bass industry. The HKD Stuttgart National Aquaculture Research Center held a research-needs forum with fish farmers representing 75% of the nation's hybrid striped bass production on March
7, 2001, to discuss the pressing research needs. Genetic improvement and production strategies were identified as the most important areas needing further research. Results of the forum have provided ARS scientists with a potential research plan to address farmer needs. Pond culture of fish is usually done adjacent to row crop agriculture that includes aerial spraying of herbicides, chemicals that potentially have lethal effects on fish. A continuing collaborative study with University of Arkansas at Pine Bluff faculty determined the effects of full-strength aerial application rates and several drift rates of the rice herbicides clomazone, pendamethalin, propanil-dry flowables, and propanil-liquid on water quality, primary production and plankton standing crops. Preliminary study results indicate that chemical and biological effects of the pesticides on culture water were negligible. Knowledge that these herbicides, necessary for rice culture, are safe to use around aquaculture
production facilities will assist the diversification of aquaculture in the Mississippi Delta. Cultured rotifers, an important constituent of live feeds for cultured larval fish, are difficult to feed automatically. A cooperative study with the ARS's Aquaculture Systems Research Unit in Pine Bluff was conducted to study the feasibility of automated feeding systems. The study resulted in the development of equations relating rotifer density in monoculture systems to amount of light transmission at several rotifer densities. This information will lead to the development of controlled, automatic rotifer feeding devices and increase sunshine bass production. High-carbohydrate feedstuffs are a relatively inexpensive dietary energy source that, unfortunately, most fish do not use well. An experiment was conducted in cooperation with Dr. Rebecca Lochmann of the University of Arkansas at Pine Bluff to investigate the relationship of starch utiliza- tion in hybrid striped bass. Carbohydrate
use was increased and fat deposition was decreased by manipulating the ration of highly-branched (amylopectin) to less-branched starch (amylose) in hybrid striped bass. Results will lead to less expensive, commercial diets for hybrid striped bass. Increased fish production may result from the use of sex steroids, although the hormones have been shown to be anabolic in some species. Hybrid sunshine bass of about seven weeks of age (5.09 + 1.7 g, mean + SD) were fed 100 mg/kg feed estrogen or methyl testosterone for three weeks at about 8% body weight per day. After 21 days the control fish were heavier than either hormone-treated groups and the estrogen-treated fish appeared to have a deformed lower jaw. Increased growth may be achieved with the addition of hormones in the correct dose to hybrid stiped bass, or may prove to retard growth and produce morphological abnormalities. In hybrid striped bass culture one sex may grow faster than the other and have the potential to increase
harves yields. The effect of gender on size was determined from several laboratory and commercially produced stocks. Preliminary data suggest that female fish are larger than male fish and that there is a higher proportion of males in market size fish. If one sex performs better than the other efforts can be directed to raise monosex populations of the desired sex. Double-crested cormorant foraging is thought to be depleting sport fish in a public fishing lake adjacent to commercial catfish ponds in southeast Arkansas. A cooperative study with University of Arkansas at Pine Bluff was initiated to determine the impact of double-crested cormorant foraging on fish populations in the lake. Preliminary results indicate high numbers of shad and yellow bass, and a lesser percent of catfish within double-crested cormorant diets. This research will result in a guidebook on fish otoliths, a description of diagnostic markings on fish consumed by double-crested cormorants and of seasonal
shifts of their diets. The depredation caused by diving ducks, primarily lesser scaup, at baitfish facilities is not well known but is thought to be high. An inclusive study of ninety-five lesser scaup, collected from baitfish facilities last year showed that depredation on baitfish was evident but less than anticipated. To determine if these conclusions resulted from a collection bias, an additional 75 scaup (foraging ducks only) were collected this year for diet analysis along with sediment samples to determine if ducks were selecting particular ponds because of the invertebrate availability. This information can be used by baitfish farmers to determine if their efforts to remove scaup from their facilities are justified in terms of cost/benefit analysis, or if additional management of pond sediments needs to be considered. Proper management of fish-eating birds requires accurate knowledge of bird numbers at catfish production facilities. Aerial surveys in a fixed-wing aircraft
were conducted for the second consecutive year to document double-crested cormorant and American white pelican numbers within the catfish production regions of southeastern Arkansas. A total of 27 and 34 roosts sites were found in 2000 and 2001, respectively. This information is important to regulating agencies, such as the USFWS, in their efforts to formulate a national cormorant management plan. The USFWS is nearing completion of a national cormorant management plan and has expressed a need for more data concerning cormorant movements to, and from, breeding grounds, and whether or not there is a constant turnover in cormorants depredating a particular area within their wintering grounds. This year will conclude a two-year study involving 25 satellite transmitters on double-crested cormorants at night roosts adjacent to catfish producing areas in four states (Alabama, Arkansas, Louisiana, and Mississippi). The preliminary findings indicate the breeding distribution is wider than
predicted. Data supplied to USFWS will help determine whether a regional reduction of the cormorant population, widespread reduction, or a combination of the two, would be effective in controlling cormorant damage to fish farmers. C. Significant accomplishments/activities that support target populations: Accomplishments directly support economic development of people in the Mississippi Delta, a special target population. The economic value of fish production greatly benefits the rural areas of the Delta regions of the southeastern U.S.that are characterized by high unemployment, low income, and economic stagnation. Commercial fish farming has a significant impact on the economy of the Delta region of the U.S. and has a potential for growth that far exceeds its present economic importance. While fish farming provides jobs to farm workers, its major impact to rural populations is jobs creation in numerous collateral industries such as aquaculture equipment manufacturing, feed mill
operations, processing and transportation.
5. Describe the major accomplishments over the life of the project including their predicted or actual impact.
The successional sequence of zooplankton sizes and types in fry culture ponds were determined and it was demonstrated that hybrid striped bass fry stocked at the right time during early zooplankton succession had improved survival from the previous average of 10% to 60%. Use of the techniques described in this research will enhance hybrid striped bass fingerling production. Fish farmers using the technique are now averaging 30-40% survival of fry over the entire spawning season. Tank culture of hybrid striped bass fry by feeding them freshwater rotifers that were also cultured in indoor vessels, was accomplished for the first time. The fry were then switched to commercially available feeds and harvested as fingerlings. This technique has the potential to allow year-round production of bass because fry will be more available on a year-round basis. Predictive equations were developed that allow farmers to estimate how long it takes to develop a rotifer bloom in fry culture ponds
based upon prevailing or normal spring air or water temperatures. Rotifers are tiny zooplankton that are required by bass for early-life survival and are only present in sufficient quantities for very short times. These equations provide farmers with the only currently available estimate of when to stock fry into ponds during the changing weather conditions of spring and will enable them to increase fry survival by stocking at the right time. For the first time hybrid striped bass fry were cultured in tanks by feeding them zooplankton harvested from ponds with a drum filter. It was also demonstrated that equations developed previously relating air and water temperatures to zooplankton succession patterns accurately predicted when maximum concentrations of rotifers and other small zooplankton would be available for harvest by the drum filter. Striped bass fingerling producers rely on fertilizers to develop rotifer and other live feeds required for the survival of their fish but
the producers do not know the optimum amounts of fertilizer to use. Equations that relate the amount of organic and inorganic fertilizers to the magnitude of rotifer and other zooplankton standing crops and to the ultimate production of sunshine bass fingerlings were developed. These equations will help sunshine bass fingerling producers to economically use fertilizers during pond culture of their fish. Many herbicides commonly used on rice were found to be compatible with pond culture of striped bass and other fish. The herbicides thiobencarb, quinclorac, halosulfuron, bensulfuron methyl, triclopyr, 2,4-D amine, molinate, clomazone, and pendamethalin did not have an adverse effect on the phytoplankton and zooplankton communities. Propanil-dry flowables and propanil-liquid inhibited photosynthesis and have the potential to be harmful to sunshine bass and other pond cultured fish. The prevalence and pathogenicity of a trematode (Centrocestus formosanus) known to infect the fountain
darter, an endangered fish was determined. This trematode also infects fathead minnows, golden shiners, hybrid striped bass and channel catfish under experimental conditions. The trematode has been found in twelve of seventeen fish in the Comal River and was first documented in the San Marcos River in the fountain darter. It is important to document the spread of such a parasite due to its proximity to the major fish culture areas of the south. This information will allow aquaculture extension agents and veterinarians to diagnose this previously unknown fish disease when it begins to appear in commercial culture areas. The antihelminthic Praziquantel was demonstrated to be an effective control agent against the yellow grub in striped bass hybrids at 0.25 ppm. The work with Praziquantel has shown that practical control of this trematode in fish is possible although registration of this chemical may be very difficult. Research with this and other antihelminth chemical control agents
will lead to a means to control this disease. A shoreline pond treatment with copper sulfate was found to effectively eliminate aquatic snails that carry fish parasites. This treatment will be used by the industry since it has a EPA label and will result in increased copper sulfate sales and decreased incidence of trematode parasitized fish. We are already aware of the sale of about 200,000 pounds of copper sulfate for use as this treatment and expect it could save the industry several hundred thousand dollars in lost fish inventories due to trematode parasites. We have given information for the treatment recommendation to be included in an extension handout of the Mississippi Extension Service, Stoneville, AR.
6. What do you expect to accomplish, year by year, over the next 3 years?
Live Feeds Research: 2002: Growth and survival of six sunshine bass genetic strains will be compared in culture ponds as a first step to develop genetically superior fish stocks. Freshwater drum fry will be tested to determine if stocking regimens applicable to sunshine bass are also pertinent to culture of other fish. In cooperation with the Aquaculture Systems Research Unit (ARS Pine Bluff, AR), work will continue with the development of a sensor/control that will ascertain rotifer densities in holding tanks and regulate their delivery to sunshine bass fingerling culture tanks. 2003: Sunshine bass fry will be cultured in tanks by being fed tank- cultured rotifers and a prepared feed that has the potential to replace brine shrimp nauplii as a live food. A comparison to a similar experiment in which brine shrimp are used will be made. The potential for catfish ponds to serve as a live feed (zooplankton) source will be determined in cooperation with the Aquaculture Systems
Research Unit (ARS Pine Bluff, AR). This may result in less dependence upon monocultured live feeds. 2004: A recirculation system will be developed in which rotifers and other zooplankton can be cultured, harvested, and fed to larval fish by means of computer control. If successful, this would represent a major cost savings to bass producers. Nutrition Research: 2002: The digestibility of a variety of fish meal substitutes will be conducted with hybrid striped bass. Fish meal is an expensive protein source in fish diets, and economic reports indicate that world supplies are limited. Reducing the amount of fish meal in hybrid striped bass diets without compromising fish health or growth would lower the cost of production. The availability of nutrients and selected minerals from common animal by-product feed ingredients will be determined. This will extend the database of practical ingredients available for commercial feed manufacturers. 2003: Work will continue on improving
carbohydrate use in hybrid striped bass by manipulating the mylose:amylopectin starch ratio of the diet as a result of support received from the USDA/IFAFS Grant Program ($103,445). This work will be conducted in collaboration with Dr. Rebecca Lochmann of the University of Arkansas at Pine Bluff. 2003: Once digestibility of fish meal substitutes have been determined for hybrid striped bass, commercial-scale pond studies will be conducted to evaluate growth and production characteristics resulting from incorporating these substitutes in practical diets. These studies should validate to producers and feed mills the efficacy of using these products. 2003: Supplemental chromium can improve carbohydrate use, decrease carcass fat, and increase muscle in a variety of farm animals including one variety of fish. Chromium compounds are also used as markers for digestibility trials in fish. Feeding trials incorporating graded levels of chromium and chromium supplements in the diet will be
conducted and the effects on growth, body composition, carbohydrate and fat metabolism, and tissue residues will be determined. If chromium also influences the way energy is used in hybrid striped bass, it is critical to determine these effects with respect to future studies aimed at evaluating feeds and feedstuffs. 2004: A number of distinct family strains of hybrid striped bass have been developed by Dr. Curry Woods at the University of Maryland (UM) which need to be evaluated in terms of basic nutritional parameters such as optimum protein level and protein:energy ratio as well as carbohydrate:lipid ratio. Tank studies will be initiated to define these requirements and delineate strains with improved performance. Physiology Research: 2002: Sexual dimorphism in hybrid striped bass will be determined from fish samples taken from laboratory stocks and acquired from commercial producers. The fastest growing sex should be identified. The sex ratio of hybrid striped bass will be
determined from the data above. Hybridization sometimes results in a sex ratio other than 1:1. These data will provide information as to how to manipulate the sex phenotype. The effect on growth of exogenous androgens or estrogens will be determined by feeding hybrid striped bass the steroids mixed in the feed. Steroids in the feed can be used to affect growth and change the sex phenotype. 2003: Experiments to produce monosex populations of male and female hybrid striped bass will begin. These experiments will follow the successful procedures used in channel catfish, tilapia, trout and yellow perch. The nature of the stress response to conditions found in aquaculture of sunshine bass will be examined, including responses to temperature and handling. These data may help in identifying better methods for handling fish. 2004: Procedures such as using water additives to reduce the stress response that occurs during the aquaculture of sunshine bass will be attempted. Methods to
determine the potential for monosex culture of sunshine bass will be continued. Bird Depredation Research: 2002: Aerial surveys with a fixed-wing aircraft, in conjunction with radio-transmitters and color leg bands affixed to double-crested cormorants, will be used to ascertain the trends in cormorant numbers, movements, and duration of use at roosting sites within catfish- producing regions of southeastern Arkansas. This will also provide much- needed information regarding the effectiveness of any upcoming management plans incorporated to regulate cormorant number within the catfish production areas of Arkansas. Additional non-lethal deterrents will be evaluated for controlling fish-eating birds at aquaculture facilities to further minimize predation. These may include additional modifications to exclusion barrier that will deter birds from landing on protected ponds, use of a hand-held laser to disperse depredating birds, and modifications to a floating replica of an alligator to
scare birds. This research should provide fish farmers with alternative, yet effective, farm-level control to minimize fish-eating birds. Information regarding the enrichment of PCB's in aquatic environments associated with double-crested cormorants will be determined for the first time at catfish production facilities. The potential health and environmental risk has not been addressed. This may provide additional impacts due to double-crested cormorant populations and further amplify the need to the USFWS for an adequate control mechanism. Completion of the cooperative study with University of Arkansas at Pine Bluff to determine the impact of double-crested cormorant foraging on a public fishing lake adjacent to catfish production facilities in southeastern Arkansas. Initial findings show catfish ranks among the top three food items. This may show additional impacts due to double-crested cormorant populations and further amplify the need to the USFWS for an adequate control
mechanism. 2002-2003: In collaboration with the USDA National Wildlife Research Center, satellite telemetry data will be compiled to produce a comprehensive map of double-crested cormorant movements. Initial findings show a much wider breeding distribution range than previously reported. This information will allow management agencies (USFWS) to make informed decisions regarding a double-crested cormorant management plan. 2003: Additional non-lethal deterrents will be evaluated for controlling fish-eating birds at aquaculture facilities. These may include further modified exclusion barriers that will deter birds from landing on protected ponds, modified hand-held laser to disperse depredating birds from fish production sites, and testing commercially available products. This research may provide fish farmers with effective farm-level control to minimize fish-eating birds. 2004: Studies to document other fish-eating bird depredations at baitfish and catfish production facilities
will be conducted since many other fish-eating bird species are increasing in numbers. Understanding which species of birds are of concern is important in future management decisions. Conclusive data is needed before actual recommendations can be made to fish farmers concerning the scale of fish-eating bird impacts. Parasitology Research: 2002: Studies to optimize a copper sulfate/citric acid marginal pond treatment for snails will continue. Specific emphasis will be placed on determining the effect of temperature on treatment efficacy. Analysis of the gastrointestinal tracts of 14 bird species for digenetic trematodes that is being carried out to determine the species and distributions of trematodes that could infect propagated fish species will continue. 2003: The intestinal analysis of the birds will be continued. Control measures for the treatment of trematodes and other parasites (particularly tapeworms) will be developed as potential chemical controls are tested for
effectiveness. Work on rapid definitive identification of parasites will also continue. Additional tests on the preference of biological control agents (black carp, red ear sunfish, and blue catfish) for three groups of snail disease vectors will continue. 2004: Identification work on trematodes found in birds will continue, as will work on the distribution and impact of the lesser-known fish trematodes. The impact of the catfish trematode (Bolbophorus confuses) on wild fish species found along the migratory pathway of the white pelican (a disease vector) will be determined.
7. What science and/or technologies have been transferred and to whom? When is the science and/or technology likely to become available to the end user (industry, farmer, other scientists)? What are the constraints if known, to the adoption & durability of the technology product?
Results of research studies and technologies developed were made available to customers and the general public through oral presentations (technical and non-technical), poster presentations at local, state, national and international meetings, and scientific papers. Research findings were given at an international conference: The Annual meeting of the World Aquaculture Society/Aquaculture America, Aquaculture 2001, Orlando, Florida. National and state meeting in which research findings were presented included annual meetings of the American Fisheries Society, Phoenix, AZ, The Fish Health Section of the American Fisheries Society, Pensacola Beach FL, Catfish Farmers of America, Biloxi MS, Catfish Farmers of Arkansas, Hot Springs AR. A meeting with major sunshine bass producers facilitated conveyance of research findings directly to a major user group. Several articles in the popular press also discussed research findings. Much of the information concerning bird depredation and
population levels and movements has also been transferred to the U.S. Fish and Wildlife Service to enable them to develop a management plan to lessen the adverse effects of birds on aquaculture crops. Methods for controlling snails with the copper sulfate- citric acid treatment in fish ponds was transferred to fish producers by the Mississippi and Arkansas Extension Services. A possible constraint to the adoption of high-amylose starch products, low-phytate grain products or fish meal substitutes in fish diets may be the final cost or supply of these products. A constraint to implementing the copper sulfate snail control may involve FDA's interpretation as to whether the copper sulfate treatment is a fish treatment or nuisance organism treatment. Studies conducted under this project have indicated no fish health or food safety problems with equivalent amounts of copper used as pond treatments and fish dips.
8. List your most important publications in the popular press (no abstracts) and presentations to non-scientific organizations and articles written about your work (NOTE: this does not replace your peer-reviewed publications which are listed below)
Popular Press: Two new scientists join the USDA. 2000. The Stuttgart Daily Leader, September, 2000. Research needs for sunshine bass aquaculture voiced in Stuttgart. 2001. The Aquaculture News. March 2001. p. 2. Sunshine bass producers hosted by Harry Dupree Center. 2001. Stuttgart Daily Leader. March 15, 2001. Hybrid striped bass growers meet in Stuttgart. 2001. Fish Farming News. v. 8. (March/April). p.15. Mitchell, A. J. Shoreline pond treatments for aquatic snails that carry the catfish trematode. 2000. The Catfish Journal. v. 15(2) p. 10-11. Radomski, A.A., D. Freeman, C. Collins, and D. Wooten. Cormorants Update and uncertainty of future management. Catfish Channel. v. 39. p. 2-3. Radomski, A.A., D. Freeman, C. Collins, D. Wooten, and D. Steward. Cormorants - Uncertainty of their future management. Global Aquaculture Advocate. v. 4. p. 72. Scott, Z.A. Stuttgart center thrives after move to USDA. 2001 Fish Farming News. v. 8. (May/June). p. 36,37,39. Wolters, W.R., G.
Waldbieser, B. Bosworth, J. Silverstein, E. Robinson, M. Li, D. Wise, D Freeman, P. Klesius, and K. Davis. Development and evaluation of USDA 103 line channel catfish. Catfish Journal. January 2001. Presentations: Davis, K.B. Sex determination in channel catfish. Stuttgart Lions Club. 2001. March. Fenech, A., S. Lochmann, M. Hoy, and A. Radomski. Who's eating the crappie? University of Arkansas at Pine Bluff, Aquaculture Days. 2000. November. Freeman, D.W. Evaluation of two single-batch and two multi-batch management strategies for production of channel catfish. Annual Meeting of the Catfish Farmers of Arkansas, Hot Springs, AR. 2001. February. Ludwig, G.M. Ecological aquaculture research activities at HKD- Stuttgart National Aquaculture Research Center. Fisheries Class from University of Arkansas at Little Rock Mar.20,2001, Fisheries class from University of West Florida April 5, 2001, Fisheries/Aquaculture class of Arkansas Tech University. April 9, 2001, Dewitt Arkansas high
school December, 2000. Ludwig, G.M. Pond fertilization and zooplankton production for fish fingerling culture. Director and staff of South Korean Fisheries Laboratory. May 16 2000. Ludwig, G.M. Pond nutrients, zooplankton, and sunshine bass Morone chrysops X Morone saxatilis fingerling production. University of Arkansas at Pine Bluff Fisheries/Aquaculture Field Day. September, 20000, Catfish Farmers of Arkansas Annual Meeting February, 2001 Ludwig, G.M. Sunshine bass fingerling production in ponds-the effect of more organic and inorganic fertilizer. American Fisheries Annual Meeting. Phoenix AR. August 19-24, 2001. Mitchell, A.J. Marginal pond treatments against aquatic snails that vector fish parasites. Annual Fish Health Section Meeting of the American Fisheries Society, Pensacola Beach, FL. September 6-8, 2000. Mitchell, A.J. Shoreline pond treatments for aquatic snails that vector parasites. Aquaculture 2001 Meeting of the World Aquaculture Society, Lake Buena Vista, FL.
January 21-15, 2001. Mitchell, A.J. Copper sulfate-citric acid treatment for controlling trematodes. Catfish Farmers of Arkansas, Hot Springs, AR. February 8- 10, 2001. Mitchell, A.J. Pelicans, Snails and Trematodes: Snail treatments. Annual Catfish Farmers of America Meeting, Biloxi, MS. February 23, 2001. Mitchell, A.J. Overview of snail vectored parasites and control methods for aquatic snails. Black Carp Meeting, Memphis, TN. May 1, 2001. Mwatela, C.,S. Lochmann, and J. Ludwig.Usw of relative abundance and condition to predict survival of hybrid striped bass (Morone chrysops X M. saxatilis fingerlings. Arkansas chapter of American Fisheries Society February 7, 2001. Radomski, A.A., D. Freeman, C. Collins, and D. Wooten. Update on bird depredation research and the status of the double-crested cormorant. Catfish Farmers of Arkansas Annual Meeting, Hot Springs, AR. February, 2001. Radomski, A.A., C. Collins, D. Wooten, and D. Freeman. Bird Depredation research. Catfish
Farmers of Arkansas Annual Meeting, Hotsprings, AR. February, 2001. Rawles, Steven, Rebecca Lochmann, and Rolfe Bryant. Amylopectin:amylose rat semipurified diets influences growth and body composition of sunshine bass, chrysops & x M. saxatilis %. World Aquaculture Society Meeting, Lake Buena Vista, Florida 2001 Werner, S. and A. Radomski. Recent double-crested cormorant research near southeastern aquaculture. Waterbird Society/Double-crested cormorant workshop. 2000.
Impacts
(N/A)
Publications
- Fenech, A.S., Lochmann, S., Radomski, A., Wooten, D., Hoy, M. Possible effects of double-crested cormorants and largemouth bass predation on crappie in an Arkansas oxbow lake. Annual meeting of the Arkansas Chapter of the American Fisheries Society, Heber Springs, Arkansas. April 2001. p. 4.
- Fenech, A.S., Lochmann, S., Wooten, D., Hoy, M., Radomski, A. Possible effects of double-crested cormorants and largemouth bass predation on crappie in an oxbow lake. Hull International Fisheries Institute. International symposium and workshop on Interactions between fish and birds: implications for management. April 2001. p. 21.
- Ludwig, G.M. Pond nutrients, zooplankton, and sunshine bass Morone chrysops X Morone saxatilis fingerling production. Annual International Conference of the World Aquaculture Society. Book of Abstracts. 2001. p. 390.
- Lochmann, S., Ludwig, J. Use of relative abundance and condition to predict survival of hybrid striped bass Morone chrysops X M. saxatilis fingerlings. Annual International Conference of the World Aquaculture Society. Book of Abstracts. 2001. p. 381.
- Mitchell, A.J., Goodwin, A.E. The isolation of Edwardsiella ictaluri with a limited tolerance for aerobic growth from channel catfish. Journal of Aquatic Animal Health. 2000. v. 12. p. 297-300.
- Mitchell, A.J., Finfish health in the United States (1609-1969): historical perspective, pioneering researchers and fish health workers, and annotated bibliography. Aquaculture 2001. v. 196. p. 347-438.
- Perschbacher, P., White, J., Ludwig, G., Miller, M., Slayton, N. Effects of rice herbicides, aerially-applied midseason, on fish pond water quality. Annual International Conference of the World Aquaculture Society. Book of Abstracts. 2001. p. 523.
- Wolters, W.R., Waldbeiser, G.C., Bosworth, B.G., Silverstein, J.T., Robinson, E.A., Li, M., Wise, D.J., Freeman, D.W., Klesius, P., Davis, K.B. Joint release of catfish line USDA 103 which has improved growth performance USDA/ARS-MSU-MAFES Germplasm Release. February 2001. Thad Cochran National Warmwater Aquaculture Center, Stoneville, MS.
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Progress 10/01/99 to 09/30/00
Outputs
1. What major problem or issue is being resolved and how are you resolving it?
One of the major constraints to expansion of culture of hybrid striped bass (the most commonly cultured Morone species) is the absence of a year-round supply of fingerlings. The current world demand for fingerlings, which are raised to market size, far exceeds the current capability of fingerling producers. The difference between demand and supply is particularly acute from late summer until the following mid-spring. The principal reasons for this are low survival of fry in ponds and the inability to produce fry year-round. Although it is now possible to spawn the parental stocks during the off-season, methods to efficiently produce zooplankton, which is required for fry production have not been developed on a year-round basis. Developing methods to produce healthy bass fry throughout the year is the objective of this research. Hybrid striped bass fry are obligate zooplankton eaters before being weaned to commercially prepared feeds at 3-6 weeks of age. Because of their small
size they initially consume rotifers and other tiny zooplankton. Methods to optimize production of rotifers and subsequently larger zooplankton are being developed, as are means of producing fingerlings year-round. Zooplankton production methods include determination of optimal types and levels of organic and inorganic fertilizers in ponds. The effects of artificial aeration and weather related phenomena such as temperature on production of zooplankton, particularly rotifers, also are being explored. Means of mass-producing zooplankton in ponds or indoor tanks on a year round basis and methods of harvesting zooplankton to feed to fish in tanks also are being developed. Although initially dependent upon live zooplankton, hybrid striped bass quickly adapt to manufactured feeds. Current formulations for hybrid striped bass feeds contain higher amounts of protein and lower amounts of carbohydrate than terrestrial livestock feeds. Typically this protein is from relatively expensive
animal or high-protein plant products. There is little information available to feed manufacturers and hybrid striped bass farmers regarding nutrient and energy availability from common foodstuffs, vitamin and mineral requirements, the interaction of feed ingredients in extruded diets, the effects of different feed ingredients on hybrid striped bass growth, nor on the use of dietary carbohydrates. Hence, the objective of the nutrition component of this project is to improve the productivity and sustainability of commercial hybrid striped bass culture in the United States by a) determining nutrient and energy availability from common feedstuffs, b) developing cost effective diets, c) evaluating alternative feeding scenarios, d) describing biological mechanisms of diet energy use, and e) developing dietary manipulations for reducing fat accumulation. Due to the rapid increase of fish-eating bird populations and the expansion of warm water aquaculture ponds in Mississippi, Arkansas,
Alabama, and Louisiana, depredation of cultured fish, particularly cultured fish, particularly catfish and other farm- raised species like bait fish, hybrid striped bass, and Chinese carps has increased. Aquaculture ponds have provided a haven for these birds especially from late fall to spring. Economic losses are increasing farm costs and reducing net returns. Primary birds associated with catfish depredation are double-crested cormorants and American white pelicans. Diving ducks, herons, and egrets also can cause losses to fish farmers. Since these birds are presently protected by federal laws (e.g., the Migratory Bird Treaty Act 1936, 1972), fish farmers are limited to non-lethal harassment methods and extremely limited lethal removal methods. Methods for dealing with the ever increasing bird populations must be developed in order to protect the warm water fish farming industry from this burgeoning drain on aquaculture production. There are two broad objectives in our
efforts at resolving the bird depredation problem. The first is to develop techniques, or a device that will non-lethally exclude birds from fishponds. The second objective is to provide data to regulatory agencies (e.g., U.S. Fish and Wildlife Service (USFWS) that will demonstrate the need of a control mechanism and to provide information on fish eating bird populations that will aid in the creation and implementation of a national management strategy. In addressing the first objective we are developing exclusion barriers that could be used to deter fish-eating birds from fishponds. Additionally, the efficacy of lasers at dispersing cormorant night roosts from catfish producing areas of Southeast Arkansas will be determined. Scare devices such as alligator decoys to deter cormorants from fishponds will be evaluated. In pursuit of the second broad objective several projects have been initiated. In efforts to track movements and determine patterns of depredation, satellite
telemetry backpacks have been attached to 25 cormorants over a four state area (Alabama, Arkansas, Louisiana, and Mississippi). Aerial surveys (two per month) have been initiated to enumerate cormorant and white pelican populations and document roost sites of catfish producing areas in Southeastern Arkansas. With the telemetry data and aerial surveys the USFWS will be provided with valuable information needed to implement a strategy aimed at alleviating the damage due to the double-crested cormorant and the white pelican. The impact of defecation from aquatic bird roosts on natural bodies of waters is being investigated. This involves testing of water conditions for fecal coliforms, and levels of phosphate, nitrate, mercury or PCB's. By tracking the water quality conditions that are associated with the increasing bird populations, researchers can identify hazardous environmental conditions before they become a human health hazard while also reenforcing the need for a national
management plan. Concurrently bird depredation researchers are conducting food habits studies of diving ducks that inhabit baitfish farms in Arkansas. The data will provide valuable information on the feeding habits of diving ducks occupying baitfish ponds and whether the time and effort devoted to their removal is justified. Birds that inhabit fish culture ponds are also vectors for several types of parasitic diseases that can greatly affect profits of fish farmers. Trematode infestations in some propagated fish are major disease problems. Most digenetic trematodes pass through bird, snail, and fish hosts. Research is focused toward resolving the digenetic trematode problem in cultured fish by developing management strategies that control the populations of the host snails, the best approach to breaking the complex life cycle of these trematodes. Studies to develop effective chemical control of fishpond snails have been initiated. The spread and impact digenetic trematodes on
cultured fish will be determined by examining the intestinal tracts of 14 aquatic bird species that carry fish trematodes.
2. How serious is the problem? Why does it matter?
Presently over 55% of commercial aquaculture in the United States is devoted to one species: channel catfish. However, striped bass and their hybrids with white bass are rapidly gaining share in the world aquaculture market. This should both diversify aquaculture production and stabilize the the U.S. fish farming industry. Increased hybrid striped bass production also will allow expansion into markets away from the southeast. Recent surveys estimate that annual Morone sp. production is increasing at a rate of nearly 10% per year. Increased output of hybrid striped bass fingerlings is necessary to expand the production of market-sized fish. In addition, development of year-round fingerling supply has been identified by the Striped Bass Growers Association as the highest priority facing the industry. Year-round supply also is necessary in order to stabilize price fluctuations related to seasonal supply and demand. Commercial producers of hybrid striped bass must economically
increase yield and decrease time to market to competitively position their products in the market place. One strategy is to reduce feed costs through least-cost formulation. Over 40% of the variable cost of hybrid striped bass farming is attributed to feed. Only a handful of relatively high-cost feedstuffs, however, have been investigated for use in hybrid striped bass diets. Research is needed on a variety of alternative ingredients for meeting the nutritional requirements of hybrid striped bass. Carbohydrates, for example, are relatively inexpensive feedstuffs. Increasing the percentage of carbohydrate used in hybrid striped bass diets could potentially lower feed costs. However, fish use dietary carbohydrate rather poorly. Excessive carbohydrate in the diet of fish can result in 1) poorer growing, less hardy fish for producers, 2) fatty fish with lower dress out percentage for processors, and 3) higher costing, potentially less nutritious products for consumers. Diets tailored to
individual species produce the fastest growing and healthiest fish. However, research must first elucidate: 1) the metabolism of nutrients and energy by hybrid striped bass from a variety of potential feed ingredients 2) the interaction of ingredients and their effects on hybrid striped bass in processed diets, 3) the metabolism of diets under different production conditions and 4) the impacts of hybrid striped bass diets on the culture system or receiving waters. Winter double-crested cormorant populations in the Delta Region of Mississippi have increased nearly 400% since 1994. Losses to the catfish industry in 1996 due to double-crested cormorant depredations were estimated at over 13 million dollars. Beginning in March 1998 the USFWS enabled fish farmers in 13 states (including Alabama, Arkansas, Florida, Georgia, Kentucky, Louisiana, Minnesota, Mississippi, North Carolina, Oklahoma, South Carolina, Tennessee, and Texas) to take double-crested cormorants on their property,
without a federal permit, however, depredations at southeastern aquaculture facilities continue. Fish-eating birds also impact sport fisheries and salmon production in the Great Lakes and eastern United States. Digenetic trematodes in fish cause serious economic losses to the aquaculture industry. The catfish trematode, Bolbophorus confusus, (a trematode in catfish muscle) is now considered one of the major disease threats in the catfish industry. Thousands of acres of catfish are infected with this trematode in Mississippi, Arkansas and Louisiana and losses among fingerling catfish are very high. The yellow grub Clinostomum complanatum infects the muscle of catfish, baitfish and Morone species. with unsightly grubs that results in consumer rejection of the product. The gill trematode, Centrocestus formosanus, impacts the health of both cultured and wild fish in Florida, Texas, Mississippi, and Georgia. It also is known to infect bait minnows, Morone species, and catfish under
experimental conditions. Since it occurs naturally just south of the major fish production area, it is a matter of economic concern. Losses in sales, deductions in prices paid at processing plants, and loss of business are the impetus behind investigating control of these parasites.
3. How does it relate to the National Program(s) and National Component(s)?
This research concerns the development of improved production systems for hybrid stripe bass, a hybrid of two Morone species, striped and white bass. The research project is directly related to ARS National Program 106 - Aquaculture. Research studies specifically relate to the following program components: Reproduction and Early Development by conducting research to develop domesticated broodstock, out of season spawning, and year-round fingerling supply of bass species and to improve production of baitfish fry; Growth, Development and Nutrition by conducting studies to improve feed formulation, feeding strategies, and feed delivery systems; and, both Aquaculture Production Systems and Sustainability and Environmental Compatibility of Aquaculture Production Systems by conducting studies to reduce or ameliorate bird depredation on cultivated fish, including development and testing of predator deterrent devices and developing information on the impact of bird depredation on fish
farming, and by conducting research to improve the understanding of vectoring of infectious agents through predatory birds.
4. What were the most significant accomplishments this past year?
A. Single Most Significant Accomplishments during FY 2000: Digenetic trematode infections in propagated fish cause major economic losses to fish farmers; therefore, there is a need to develop control methods. A perimeter pond treatment (the first of its type) was developed that effectively controls snails that vector the trematodes while being safe for the propagated fish species in the treated pond. An application of a chemical combination of copper sulfate and citric acid applied in the water in a two-meter wide swath along the edge of a pond killed over 95% of the snails in two replicated studies. This chemical treatment will be a major breakthrough in controlling snails that carry digenetic trematodes. B. Other significant accomplishments: Striped bass fingerling producers rely on fertilizers to develop rotifer and other zooplankton populations required for the survival of their fish but the producers do not know the optimum amounts of fertilizer to use. Research was conducted
to compare the development of zooplankton crops and survival of hybrid striped bass fingerlings in culture ponds fertilized with multiple amounts of a standard organic/inorganic fertilization protocol. Equations were developed that related the amount of fertilizer used to the magnitude of rotifer and other zooplankton standing crops and to the ultimate production of fingerlings. These equations will help sunshine bass fingerling producers to economically use fertilizers during pond culture of their fish. Pond culture of fish is usually done adjacent to row crop agriculture that includes aerial spraying of herbicides, chemicals that potentially have lethal effects on fish. A collaborative study with University of Arkansas at Pine Bluff faculty determined the effects of full strength aerial application rates and several drift rates of the rice herbicides, thiobencarb, quinclorac, halosulfuron, bensulfuron methyl, triclopyr, 2,4-D amine, and molinate on water quality, primary production
and plankton standing crops. Preliminary study results indicate that chemical and biological effects of the pesticides on culture water were negligible. Knowledge that these herbicides, necessary for rice culture, are safe to use around aquaculture production facilities will assist the diversification of aquaculture in the Mississippi Delta. Impacts of wading bird depredations at baitfish facilities have not been accurately documented. Studies determined the impact of wading birds on baitfish production through a cooperative study with USDA/APHIS to investigate the impact of these birds on baitfish farmers in Arkansas. Wading birds were found to have a highly detrimental, but localized effect on baitfish production. This information will be available to regulatory agencies to demonstrate the impacts of wading birds to the baitfish industry and support the need for adequate control measures. The impacts of diving duck (primarily lesser scaup) depredations at baitfish facilities are
not accurately quantified. Ninety-five lesser scaup were collected from baitfish facilities in the Lonoke County AR to determine their food habits. Although some depredation on baitfish was evident it was less than anticipated. The aquaculture industry will use this information to determine if their efforts to remove scaup from their facilities are justified in terms of cost/benefit analysis. The USFWS has initiated the process of developing a national cormorant management plan and has expressed a need for more data concerning cormorant population movements to and from breeding grounds, and whether or not there is a constant turnover in cormorants depredating a particular area within their wintering grounds. Twenty-five satellite transmitters were attached to cormorants at night roosts adjacent to catfish producing areas in four states (Alabama, Arkansas, Louisiana, and Mississippi) and are tracking the transmitters to obtain daily information on bird movements during the next two
years. The USFWS is studying the first year's movement data as background information to develop a national cormorant management plan. Data supplied to USFWS will help determine whether a regional reduction of the cormorant population, widespread reduction, or a combination of the two, would be effective in controlling cormorant damage to fish farmers. The USFWS requested data concerning cormorant populations in fish producing areas so that an effective national management strategy can be developed. Aerial surveys in a fixed wing aircraft were conducted to document cormorant population levels in catfish producing regions of Southeastern Arkansas. These surveys were the first documentation of current use and seasonal trends in populations of double-crested cormorants inhabiting catfish producing areas. This will provide factual data for the USFWS in developing a national cormorant management plan. C. Significant accomplishments/activities that support special target populations: The
economic value of fish production greatly benefits the rural areas of the Delta regions of the southeastern U.S. that are characterized by high unemployment, low income and economic stagnation. The development of new production strategies, disease prevention, and methods to control fish- eating birds would stimulate further growth of the industry and thus provide jobs creation not only on the farm, but in numerous collateral industries such as aquaculture equipment manufacturing, feed mill operations, processing and transportation. D. Progress Report Effective snail control agent developed. The first scientifically tested and proven marginal pond treatment for controlling snails that carry important fish pathogens was developed. A copper sulfate-citric acid marginal pond treatment was shown to be effective in controlling snails that carry fish parasites (digenetic trematodes) and safe for the propagated fish held in the same pond. The treatment rate was 10 lbs of copper sulfate and
1 lb of citric acid put in a minimum of 70 gal of stock water and sprayed over 250 linear ft of pond perimeter water (0 to 6 ft from the bank).
5. Describe the major accomplishments over the life of the project including their predicted or actual impact.
The successional sequence of zooplankton sizes and types in fry culture ponds were determined and it was demonstrated that hybrid striped bass fry stocked at the right time during early zooplankton succession had improved survival from the previous average of 10% to 60%. Use of the techniques described in this research will enhance hybrid striped bass fingerling production. Fish farmers using the technique are now averaging 30-40% survival of fry over the entire spawning season. Tank culture of hybrid striped bass fry by feeding them freshwater rotifers that were also cultured in indoor vessels, was accomplished for the first time. The fry were then switched to commercially available feeds and harvested as fingerlings. This technique has the potential to allow year-round production of bass because fry will be more available on a year-round basis. Predictive equations were developed that allow farmers to estimate how long it takes to develop a rotifer bloom in fry culture ponds
based upon prevailing or normal spring air or water temperatures. Rotifers are tiny zooplankton that are required by bass for early-life survival and are only present in sufficient quantities for very short times. These equations provides farmers with the only currently available estimate of when to stock fry into ponds during the changing weather conditions of spring and will enable them to increase fry survival by stocking at the right time. For the first time hybrid striped bass fry were cultured in tanks by feeding them zooplankton harvested from ponds with a drum filter. It was also demonstrated during that equations developed previously relating air and water temperatures to zooplankton succession patterns accurately predicted when maximum concentrations of rotifers and other small zooplankton would be available for harvest by the drum filter. Studies determined the prevalence and pathogenicity of a trematode (Centrocestus formosanus) known to infect the fountain darter, an
endangered fish. This trematode also infects fathead minnows, golden shiners, hybrid striped bass and channel catfish under experimental conditions. The trematode has been found in twelve of seventeen fish in the Comal River and was first documented in the San Marcos River in the fountain darter. It is important to document the spread of such a parasite do to its proximity to the major fish culture areas of the south. This information will allow aquaculture extension agents and veterinarians to diagnose this previously unknown fish disease when it begins to appear in commercial culture areas. Studies demonstrated that the antihelminthic, Praziquantel was an effective control agent against the yellow grub in striped bass hybrids at 0.25 ppm. The work with Praziquantel has shown that practical control of this trematode in fish is possible although registration of this chemical may be very difficult. Research with this and other antihelminth chemical control agents will lead to a means
to control this disease. Question 6. Live Feeds Research: 2001 The effects of aeration upon the development of zooplankton populations at high levels of organic and inorganic fertilization during summer will be determined in order to assist fish farmers in deciding what levels of fertilizers to use and if aeration will allow them to use even higher fertilization levels when appropriate. Work will continue on the development of a sensor/control that will determine rotifer densities in holding tanks and regulate their delivery to sunshine bass fingerling culture tanks. 2002 A model equation relating ammonia, nitrate, phosphate, and temperature and dissolved oxygen concentrations to concentrations of rotifers, copepod nauplii, copepods and cladocerans will be developed from sunshine bass culture ponds. This will assist fish farmers in determining what level of fertilization is appropriate for their type of fry culture. 2003 A recirculation system will be developed in which
rotifers and other zooplankton can be cultured, harvested and fed to larval fish by means of computer control. If successful, this would represent a major cost savings to bass producers. Nutrition Research: 2001 Digestibility trials will be conducted with a variety of feedstuffs. The availability of phosphorus and selected minerals from common and low-phytate feed ingredients will be determined. This will extend the database of practical ingredients available for commercial manufacturers of hybrid striped bass feed. 2002 Supplemental chromium can improve carbohydrate use, decrease carcass fat, and increase muscle in a variety of farm animals including one variety of fish (tilapia). Chromium compounds are also used as markers for digestibility trials in fish. Hence, feeding trials incorporating graded levels of chromium and chromium supplements in the diet will be conducted and the effects on growth, body composition, carbohydrate and fat metabolism, and tissue residues will be
determined. If chromium also influences the way energy is used in hybrid striped bass, it is critical to determine these effects as well as tissue residues with respect to future studies aimed at evaluating feeds and feedstuffs. 2003: Conjugated linoleic acid (CLA), is a naturally occurring fatty acid in dairy products and meat. CLA has gained interest as a potential dietary supplement because it decreases body fat in some animals. Feeding trials that incorporate graded levels of CLA in diets for sunshine bass will be conducted and the effects on growth, body composition, carbohydrate and fat metabolism, and tissue residues will be determined. This will be one of the first attempts to investigate the possible beneficial effects of CLA supplementation on fat accumulation in fish. Bird Depredation Research: 2001: Aerial surveys will be conducted with a fixed wing aircraft to document cormorant population levels in catfish producing regions of Southeastern Arkansas. This information
will identify seasonal and yearly trends in cormorant populations depredating catfish production facilities in Southeastern Arkansas. This will also supply baseline information regarding cormorant populations and provide a measure to determine the effectiveness of future management plans. 2001: Three potential non-lethal deterrents will be evaluated for control of fish-eating birds occurring at aquaculture facilities. These include; an exclusion barrier which will deter birds from landing on protected ponds; use of a high powered hand held laser to disperse depredating birds from fish producing locales; a floating alligator silhouette to scare birds. This research may provide fish farmers with effective farm-level control of of fish eating birds. 2002: Baseline information regarding the enrichment of nutrients (particularly phosphorus, nitrate, nitrite, and ammonia), mercury and PCB's, and coliforms in aquatic environments associated with double crested cormorant night roosts will
be documented. This may provide additional impacts due to double-crested cormorant populations and further amplify the need to the USFWS for an adequate control mechanism. 2002: A cooperative study with University of Arkansas at Pine Bluff will be conducted to determine the impact of double crested cormorant foraging on a sportfishing lake in Southeastern Arkansas. This may show additional impacts due to double-crested cormorant populations and further amplify the need to the USFWS for an adequate control mechanism. 2002-2003: In collaboration with the USDA National Wildlife Research Center, satellite telemetry data will be compiled to produce a comprehensive map of double-crested cormorant movements. This information will allow management agencies (USFWS) to make informed decisions regarding a double-crested cormorant management plan. 2003: Studies to document scaup depredations at baitfish production facilities will be conducted. Conclusive data is needed before actual
recommendations can be made to fish farmers concerning the true nature of scaup impacts, as there is a good chance that seasonal variation exists. Parasitology Research: 2001: The copper sulfate/citric acid marginal pond treatments for snails will be optimized. Specific emphasis will be placed on determining the effect of temperature on treatment efficacy. Analysis of the gastrointestinal tracts of 14 bird species for digenetic trematodes will be carried out to determine the species and distributions of trematodes that could infect propagated fish species. Methods for the rapid definitive identification of parasites including trematodes will be initiated. 2002: The intestinal analysis of the birds will be continued. Control measures for the treatment of trematodes and other parasites (particularly tapeworms) will be developed. Work on rapid definitive identification of parasites will continue. 2003: Identification work on trematodes found in birds will continue as will work on
the distribution and impact of the lesser-known fish trematodes. Management and chemical control options for non-trematode parasitic diseases of propagated fish will be studied.
6. What do you expect to accomplish, year by year, over the next 3 years?
7. What science and/or technologies have been transferred and to whom? When is the science and/or technology likely to become available to the end user (industry, farmer, other scientists)? What are the constraints if known, to the adoption & durability of the technology product?
Results of research studies and technologies developed were made available to customers and the general public through oral presentations (technical and non-technical), poster presentations at local, state, national and international meetings, and scientific papers. Research findings were given at two international conferences: Aquaculture 2000, Nice, France; and the World Aquaculture Society, New Orleans, LA. Several articles in the popular press discussed research findings. Much of the information concerning bird depredation and population levels and movements has also been transferred to the U.S. Fish and Wildlife Service to enable them to develop a manage plan to lessen the adverse effects of birds on aquaculture crops. Methods for controlling snails with the copper sulfate- citric acid treatment in fish ponds was transferred to fish producers by the Mississippi and Arkansas Extension Services
8. List your most important publications in the popular press (no abstracts) and presentations to non-scientific organizations and articles written about your work (NOTE: this does not replace your peer-reviewed publications which are listed below)
Popular Press: Collins, C.M. Research activities at the Harry K. Dupree Stuttgart National Aquaculture Research Center. "You asked for it", Aquaculture Magazine. 2000. 26(2):85-87 Rawles, S. D. and Gatlin, D. M. Fresh Research: Advances in hybrid striped bass nutrition. Feed Management January 2000 51(1): 19-22. Anonymous. Survival chances brighten for sunshine bass. Aquaculture Magazine. 2000 26(3):26. Plunkett, C. Demand for large fillets difficult to meet. Aquaculture News. February 2000. Hardin, B. Sunshine bass makes a splash! Agricultural Research. 2000. 48(2):16. Arkansas Democrat Gazette, February 15, 2000. Markets hooked on catfish. Arkansas Democrat Gazette June, 4 2000. Cormorants ruffle farmers' feathers. Presentations: Collins, C.M. Research activities at HKD-SNARC. Minnesota Aquaculture Association Annual Meeting, Hinckley, Minnesota. February 18, 2000. (250 attendees). Lochmann, S. and G. Ludwig. Morphometric and lipid-based measures of condition for sunshine
bass fry. Joint meeting of the Texas, Arkansas, and Louisiana Chapters of the American Fisheries Society. 1999. (40 attendees). Ludwig, G.M. Culture systems research at HKD-SNARC with emphasis on sunshine bass fingerling culture. Presentation to potential Illinois fish farmers who were sponsored by PrairieLands Seafood. March 15, 2000. (75 attendees). Mitchell, A.J. Presented a talk on the digenetic trematode in catfish to the Louisiana Catfish Farmers at Jonesville, LA, on October 25-26, 1999. Wooten, D.E. Appraisal and support of a roost dispersal objective for the Lake Village area of Arkansas. Arkansas Catfish Producers Meeting at Lake Village on December 3, 1999 (50 attendees). Wooten, D.E. Purpose, accomplishments, and objectives of the Bird/Aquaculture Conflicts research program at HKDSNARC. Location Meeting of ARS employees, HKDSNARC conference room, Stuttgart, Arkansas. January 11, 2000. (35 attendees). Wooten, D.E. Demonstration of techniques involved in diving duck
food habits research and coinciding presentation of scientific method and purpose of research. Dewitt High School Biology Classes, Dewitt, Arkansas. May 1, 2000. (125 attendees). Wooten, D.E. Testimony given by researchers from USDA/ARS/SPA/HKDSNARC at the Cormorant Scoping Meeting, USFWS, Little Rock, AR, June 5, 2000 (+100 attendees).
Impacts
(N/A)
Publications
- Ludwig, G.M. and S. Lochmann. Culture of sunshine bass, Morone chrysops X M. saxatilis, fry in tanks with zooplankton cropped from ponds with a drum filter. Journal of Applied Aquaculture. 2000. 10(2):
- Mitchell, A. J. A copper sulfate-citric acid treatment for control of snails transmitting fish parasites. Proceedings of Fish Health Section, American Fisheries Society. 2000.
- Mitchell, A. J., and A. E. Goodwin. Evidence that enteric septicemia of catfish (ESC) was present in Arkansas by the late 1960s: New insights into the epidemiology of ESC. Journal of Aquatic Animal Health. 1999. 11:175-178.
- Buyukates, Y., S. D. Rawles and D. M. Gatlin, III. Phosphorus fractions of various feedstuffs and apparent phosphorus availability to channel catfish. North American Journal of Aquaculture. 2000. 62:184-188.
- Counce, P. A., T. C. Keisling, and A. J. Mitchell. A uniform, objective, and adaptive system for expressing rice development. Crop Science. 2000. 40:436-443.
- Lochmann, S. and J. Ludwig. Morphometric and lipid class composition as measures of condition for sunshine bass fry. U.S. Chapter of the World Aquaculture Society. 2000. Book of Abstracts. p. 204.
- Ludwig, G.M. Effect of environmental factors on development of rotifer and copepod nauplii populations in sunshine bass Morone chrysops X M. saxatilis nursery ponds without fish. Journal of the World Aquaculture Society. 2000. 31:1-13.
- Ludwig, G.M. and S. Lochmann. Use of zooplankton cropped from ponds to culture sunshine bass, Morone chrysops X M. saxatilis in tanks. Annual International Conference of the World Aquaculture Society. 2000. Book of Abstracts. p. 421.
- Ludwig, G.M. and S. Lochmann. Culture of sunshine bass Morone chrysops X M. saxatilis fry in tanks with zooplankton cropped from ponds. U.S. Chapter of the World Aquaculture Society. 2000. Book of Abstracts. p. 205.
- Ludwig, G.M. and S. Lochmann. Culture of sunshine bass, Morone chrysops X M. saxatilis, fry in tanks with zooplankton cropped from ponds with a drum filter. Journal of Applied Aquaculture. 2000. 10(2):
- Mitchell, A. J. A copper sulfate-citric acid treatment for control of snails transmitting fish parasites. Proceedings of Fish Health Section, American Fisheries Society. 2000.
- Mitchell, A. J., and A. E. Goodwin. Evidence that enteric septicemia of catfish (ESC) was present in Arkansas by the late 1960s: New insights into the epidemiology of ESC. Journal of Aquatic Animal Health. 1999. 11:175-178.
- Buyukates, Y., S. D. Rawles and D. M. Gatlin, III. Phosphorus fractions of various feedstuffs and apparent phosphorus availability to channel catfish. North American Journal of Aquaculture. 2000. 62:184-188.
- Counce, P. A., T. C. Keisling, and A. J. Mitchell. A uniform, objective, and adaptive system for expressing rice development. Crop Science. 2000. 40:436-443.
- Lochmann, S. and J. Ludwig. Morphometric and lipid class composition as measures of condition for sunshine bass fry. U.S. Chapter of the World Aquaculture Society. 2000. Book of Abstracts. p. 204.
- Ludwig, G.M. Effect of environmental factors on development of rotifer and copepod nauplii populations in sunshine bass Morone chrysops X M. saxatilis nursery ponds without fish. Journal of the World Aquaculture Society. 2000. 31:1-13.
- Ludwig, G.M. and S. Lochmann. Use of zooplankton cropped from ponds to culture sunshine bass, Morone chrysops X M. saxatilis in tanks. Annual International Conference of the World Aquaculture Society. 2000. Book of Abstracts. p. 421.
- Ludwig, G.M. and S. Lochmann. Culture of sunshine bass Morone chrysops X M. saxatilis fry in tanks with zooplankton cropped from ponds. U.S. Chapter of the World Aquaculture Society. 2000. Book of Abstracts. p. 205.
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