ASSESSING ENHANCEMENTS TO RECREATIONAL FISHING PONDS USING STABLE ISOTOPE ANALYSES

• Sponsoring Institution: National Institute of Food and Agriculture
• Project Status: COMPLETE
• Funding Source: HATCH
• Reporting Frequency: Annual
• Accession No.: 0228014
• Project Start Date: Oct 1, 2011
• Project End Date: Sep 30, 2013
• Program Code: [(N/A)]- (N/A)

Recipient Organization
AUBURN UNIVERSITY
108 M. WHITE SMITH HALL
AUBURN,AL 36849

Performing Department
Fisheries & Allied Aquaculture

Non Technical Summary
Small impoundments (often referred to as "ponds") are common and abundant features on the landscape with more than 2 million on privately-owned land across the U.S. with a high concentration in the Southeast. These ponds are used for a wide array of purposes, but the most common use is recreational fishing. The typical fish community that is established has largemouth bass as the top predator and bluegill as the primary prey; this dates back to some of Homer Swingle's earliest work here at Auburn University relative to producing a "balanced" fish population. More recently, there is interest in managing these pond fish communities more intensively, often with the goal of maximizing fish catch, developing a trophy fishery, and maintaining a sustainable long-term harvest. Management enhancements that can help to attain these goals include chemical fertilization, as well as providing supplemental pellet feed for bluegill and providing threadfin shad as a supplemental prey fish for largemouth bass. Although these enhancement techniques are often used, it is not consistently clear whether they work or how they act in a pond food web. Here we describe work that we propose that will allow us to quantify how pelleted feed influence pond communities, through direct effects on bluegill and indirectly on largemouth bass (mediated through bluegill), and also to quantify how threadfin shad influences largemouth bass populations. Our approach will be to combine field sampling and pond experiments with stable isotope analyses that will allow us to quantify food web effects of these supplemental enhancements in these widely-distributed systems. Stable isotope analysis is a chemical technique that will allow us to trace sources of food (pellets vs natural food sources) through the bluegill or threadfin shad to the largemouth bass. This project will provide information support to a significant rural extension program in pond management. Results of this work will provide scientific underpinnings to recommendations made by regional agents and specialists in the enhancement of pond fish populations. Both individual private pond owners and those that operate pay-to-fish and hunting/fishing resorts will benefit from these recommendations. Given that pond fishing businesses are most often found in the some of the most economically challenged parts of Alabama, any support that can help them attract more anglers would be significant. The project will train a graduate student and result in the production of a thesis, at least one journal article, and 1-3 extension publications.

Animal Health Component

(N/A)

Research Effort Categories

Basic

(N/A)

Applied

(N/A)

Developmental

(N/A)

Classification

Knowledge Area (KA)	Subject of Investigation (SOI)	Field of Science (FOS)	Percent
135	0810	1010	20%
135	0810	1070	30%
135	0812	1010	25%
135	0812	1070	25%

Knowledge Area
135 - Aquatic and Terrestrial Wildlife;

Subject Of Investigation
0810 - Finfish; 0812 - Fish habitats;

Field Of Science
1070 - Ecology; 1010 - Nutrition and metabolism;

Keywords

fishing ponds

largemouth bass

bluegill

threadfin shad

forage enhancements

stable isotopes

pelleted feed

Goals / Objectives
Objectives -From our research effort we will determine the following in recreational largemouth bass - bluegill fishing ponds. -Determine the relative contribution of pelleted feed to growth and reproduction of bluegill under varying feeding enhancements -Determine the contribution of pelleted feed via enhancement of the bluegill to the growth of largemouth bass -Determine the effect of threadfin shad on the foodweb and therefore the growth of largemouth bass From our extension effort we will: -Integrate the results of the research effort into our recommendations for enhancements to recreational fishing ponds. -Increase the efficiency of the use of feeds as an enhancement -Provide appropriate expectations for pond enhancements Outputs Our research efforts will result in at least 1 Master's thesis, 1 journal article in a peer-reviewed scientific journal, and presentation of results at one regional and one national scientific meeting. This project will allow us to train 1 MS graduate student preparing them for further graduate training, or to compete for jobs in management agencies or the private consultancies. Through our extension work, we will reach pond owners through a combination of pond management workshops, extension literature (both paper and web-based), and videos. While we cannot guarantee that our proposed research will dramatically alter pond management strategies, it is clear that our current extension literature concerning fish pond enhancement is in need of revision and upgrading. We will take this opportunity to improve this aspect of ACES pond management program. All outputs will be completed within 1 year of the end of funding (September 30, 2013).

Project Methods
We will test the effect of pellet feeding and threadfin shad on fish growth in ponds using sampling in established ponds, pond experiments, and stable isotope analysis. Stable isotope analysis relies on important elements being present in the environment in different isotopes some of which are stable. The ratio of isotopes are influenced by biological processes such that food source and tropic position can be identified. The ratio of 12C and 13 C indicate the source of production and the ratio of 14N and 15N indicate the trophic positions of organisms. Stable isotope ratios of these elements will help us determine the influence of pellet feed and threadfin shad on pond fish communities through contribution to growth and reproduction of bluegill and largemouth bass. In ponds at Auburn and in privately owned fishing ponds we will sample bluegill populations in ponds that are fed with pellet feeders (n=3), without pellet feed (n=3), and in ponds with pellet feeders and threadfin shad (n=3). Both largemouth bass and bluegill will be collected using boat-mounted electrofishing. In each pond we will use electrofishing around the pellet feeder and in areas at a distance away from the feeder. Bass and bluegill will be weighed and measured and a subsample will be euthanized according to appropriate animal care protocols and placed on ice for further analyses in the lab. Using information from diet analysis of the collected fishes, we will collect food organisms using nets and dredges. Muscle tissue from each fish and other forage organisms will be frozen for stable isotope analysis. At the Auburn Fisheries experiment station we will conduct an experiment to calibrate the stable isotope/mixing model analyses and determine how the rate of pellet feeding relates to shifts in ratios of stable isotopes of carbon and nitrogen. Ten 0.1-ha ponds will be stocked with 250 fingerling bluegill and 25 150-250 mm largemouth bass. Feeding treatments of 0, 0.2, 1, 2.5, and 4 kg per ha per day will be assigned to ponds and feeding will begin in March. The feed will be 36% protein floating catfish fingerling. Fish populations will be sampled monthly with boat mounted electrofishing. At the middle and end of the experiment a subsample of largemouth bass and bluegill will be collected from each pond for stable isotope analysis. Diets of bluegill and largemouth bass will be enumerated. Largemouth bass and bluegill will be aged using otoliths. For older fish annular age will be determined. A subsample of juvenile fish will be aged to the nearest day of life using otolith daily rings. Samples of feed, fish muscle tissue, and prey species will be processed using standard methods for stable isotope mass spectroscopy and analyzed at Southern Illinois University. Analysis of the data to obtain the estimated contribution of pelleted feed to the growth of bluegill and largemouth bass will be done using mixing models. Follow-ups with pond owners provided information (extension publications) and recommendations will allow us to determine the acceptance and changes in practices related to pellet feeding and stocking threadfin shad.

Progress 10/01/11 to 09/30/13

Outputs
Target Audience: The target audiences of this project are scientists, extension personnel, agency personnel, and consultants who work with recreational bass-bluegill fishing ponds. Of course the ultimate audience are the pond owners, anglers, and managers who might benefit from our results. During the final year of the project, presentations were made to state, regional, and national meetings of biologists. Our results were also highlighted in workshops presented to pondowners in Alabama and in one multi-state forum in Georgia. Finally, individual pond owners benefited pay directly participating in the project. Each pond owner who allowed us to sample their pond were provided a management plan that informed them about our project, the status of their pond, and some appropriate strategies they might employ to meet their goals. Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided? The graduate student on the project has been trained in freshwater fisheries science, quantitative methods, and small impoundment management all as part of his educational experience at Auburn University. This specific project has reinforced all aspects of that training plus has provided training in analysis of stable isotopes and the models necessary to interpret them. We also trained lab technicians (both students and permanent staff) in many of the lab techniques. This project supported undergraduate training. An undergraduate hourly technicain was trained in fish sampling and lab processing of stable isotopes. Another senior undergrauate completed a special project experiment to test the relative digetibility of various feed type by bluegill. Unfortunately, the project was plagued by both unanticpated disease issues and design flaws; however, the student was trained in basic experimental design and analysis. In collaboration with an National Science Foundation Research Experience for Undergradates (REU) funded program ( Dr. Alan Wilson, principle investigator) this project hosted 2 undergraduates (1 in 2012 and 1 in 2013). These students were recruited nationally. The REU students were trained in basic limnology and pond ecology and management. They gained experience in fisheries sampling techniques, estimatine ages, fsh diet analysis, and statistical approaches. The REU student trained in 2012 is now enrolled in graduate school at another institution. The graduate student and the REU undergraduates have presented their work in both formal and informal settings. The graduate student has developed strong communications skills working directly with pond owners providing them the results of his sampling and management plans to help them meet their individual goals with their ponds. How have the results been disseminated to communities of interest? In 2013, the priniciple investigators in ths project helped organize and present in 3 pond management workshops through the Alabama Cooperative Extension System where portions of the results of this work were presented to the public. The graduate student has presented the results of this project at regional and state professional meetings where state fisheries biologists, extension professonals, and private consultants all were present. This audience works broadly with the pond owning public. Reporting of the results of this researchand other pond management concerns have been provided to the public and extension personnel via our Facebook Page, Alabama Extension Fisheries and Pond Management. What do you plan to do during the next reporting period to accomplish the goals? Nothing Reported

Impacts
What was accomplished under these goals? Pond enhancements are commonly used to increase fish production or enhance angling opportunities, but their effects are often not evaluated. We used stable isotope analysis to estimate the contribution of different rations of pellet feed to bluegill (Lepomis macrochirus) reproduction and ultimately to largemouth bass (Micropterus salmoides) growth in both the presence and absence of threadfin shad (Dorosoma petenense). We used two approaches: a controlled small pond experiment and sampling of established ponds. We stocked 10 0.1-ha ponds with bluegill and largemouth bass in February of 2012, and fed them one of five feed rations (0, 1.3, 1.9, 3.2, and 4.4 kg – ha-1 d-1). Ponds were sampled through the summer and harvested in August. We also sampled 30 established ponds, 10 with neither threadfin shad or pellet feed, 10 that received only pellet feed, and 10 that received pellet feed and contained threadfin shad. While the controlled pond experiment was conducted and 9 of the establish ponds were sampled in 2012, stable isotope analysis and data analyses continued through 2013 and into 2014. The other 21 established private ponds included in the sampling and analysis were sampled in the spring and summer 2013. All the data have been collected including field sampling and lab analyses. Statistical analysis is complete. The most significant impact of our work at this stage are changes in knowledge. We have learned and confirmed some of the impacts of feed and threadfin additins to bass-bluegill ponds. We have also learnd some of the limitation to stable isotope based analayses to tracing sources of nutrients through these pond food webs. In summary, our project documented that there were strong potential effects of feed addtions on the growth and condition of bluegill in ponds.As expected, bluegill growth and reproduction increased with increasing feed ration. Stable isotope results indicate that the nitrogen isotopic signatures showed clear separation among trophic levels, as well as a significant negative relationship for bluegill with increasing feed rations. The nitrogen isotopic signatures of largemouth bass showed similar trends to bluegill at high feed rations in the controlled small pond experiment. Pellet feed contributed to the carbon isotopic signatures of bluegill and largemouth bass across pond types in the established pond study independent of threadfin shad presence. Observed effects on growth and reproduction of bluegill as well as shifts in isotopic signatures of both largemouth bass and bluegill show enhancement effects at multiple trophic levels of adding pelleted feed to recreational largemouth bass-bluegill ponds; however, the impact of this enhancement on growth and production of largemouth bass needs further research. It is clear that the rate of feed delivery is not well documented and is highly variable by pond owners. This added variation combined with differences among ponds in other aspects of management (harvest rate, vegetation conrol, fertization, etc.) confounded our ability to decern the effects of pelleted feeds and even stable istope transfer among trophic levels, Future studies where long-term protocols could be established and maintained could be powereful approaches to determine the relative contribution of enhancements (feeds, living forage stocking, or physical enhancements) to meeting the goals of pond owners. The graduate student on the project, Keith Henderson, is currently completing the draft of his thesis in anticipation of defending the work this before May 2014. We have exceeded the objective of presenting the work at a national and a regional meeting by also presenting at our state fisheries association meeting as well. 2 extension publications (1 video and 1 web-based calculator) were completed and published online. Another publication on the improper used of mussels as forage enhacements in ponds is in editorial review. We anticipate further publications both peer-reviewed research and peer-reviewed extension by the end of September 2014.

Publications

• Type: Conference Papers and Presentations Status: Published Year Published: 2014 Citation: Henderson, K., R.A. Wright, and D.R. DeVries. 2014. Assessing effects of supplemental pellet feeding and threadfin shad addition to recreational fishing ponds using stable isotope analysis. Annual Meeting of the Southern Division of the American Fisheries Society, Charleston, SC
• Type: Conference Papers and Presentations Status: Published Year Published: 2013 Citation: Henderson, K., R.A. Wright, and D.R. DeVries. 2014. Assessing effects of supplemental pellet feeding and threadfin shad addition to recreational fishing ponds using stable isotope analysis. Annual Meeting of the the American Fisheries Society, Little Rock, AR
• Type: Conference Papers and Presentations Status: Published Year Published: 2014 Citation: Henderson, K., R.A. Wright, and D.R. DeVries. 2014. Assessing effects of supplemental pellet feeding and threadfin shad addition to recreational fishing ponds using stable isotope analysis. Annual Meeting of the Alabama Fisheries Association, Eufaula, AL
• Type: Journal Articles Status: Published Year Published: 2013 Citation: Woodard, S.R.*, R.A. Wright, and D.R. DeVries. 2013. Growth and survival of largemouth bass following supplemental feeding of bluegill in small impoundments. North American Journal of Fisheries Management. 33:170-177.
• Type: Theses/Dissertations Status: Other Year Published: 2014 Citation: Henderson, H.K. Assessing enhancements, specifically supplemental feeding to recreational fishing ponds using stable isotope analysis. Masters of Science, Thesis. Auburn University, AL.

Progress 01/01/12 to 12/31/12

Outputs
OUTPUTS: The overall objective of the project is to determine the impact of forage enhancements on the bluegill and largemouth bass populations in recreational fishing ponds using stable isotopes to trace effects through the food webs. The first full year of research was completed. To accomplish this project a Masters student was recruited. A pond scale feeding experiment was conducted to determine the relative effect of feeding pelleted catfish feed to bluegill, Lepomis macrochirus, on the stable isotopes of nitrogen and carbon for muscle tissue of both bluegill and largemouth bass, Micropterus salmoides. Fish were stocked in 0.1 ha ponds in March 2013. Feed was provided at 5 treatment rates ranging from 0 to 4.4 kg per ha per day with 2 replicate ponds per feeding rate. Fish were sampled at the beginning, mid-point and end of the experiment in August. Samples of the feed, other potential food organisms (zooplankton, insects, and crayfish) and tissue from the fish were dried, ground and samples sent to collaborators at Southern Illinois University for stable isotope analysis. To determine the effect of pellet-feeding on established systems, 12 privately-owned ponds were sampled that had different levels of feeding and some with the additional fish forage species threadfin shad, Dorosoma petense. Pond owners who participated in the study were provided a management plan to help them maintain or enhance their system. Over 800 fish samples and 50 samples of potential forage species are currently being analyzed for stable isotope signature. These analyses should allow us to determine the relative contribution of pelleted feeds as an enhancement to the growth of bluegill and potentially largemouth bass in recreational fishing ponds. Preliminary results suggest that there are definite differences among established ponds in stable isotope signature although it will not be clear how much of these differences are due to feed additions until analyses are complete for the forage organisms and the pond experiment. We anticipate completion of all samples for stable isotopes from the first year of the project this spring. Additional established ponds will be sampled in 2013. PARTICIPANTS: This project has certainlly contributed to the training and professional development of a Masters student who will use the data collected as the basis of his thesis. The student and technicians involved have learned new techniques relevnat to stable istope analysis. We have provided management plans for the the owners of the private pond sampled in the project. TARGET AUDIENCES: The target audience for this project would include pond owners, pond managers, Extension and naturalresource agency personnel who provide management recommendations, and academicians interested in the dynamics of enhanced pond systems. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.

Impacts
This project will provide pond managers and extension personnel information relevant to the efficacy of pellet-feeding to the enhancement of bluegill and largemouth bass populations in recreational fish ponds. The relative impact of adding threadfin shad on pond food webs will also be determined.

Publications

• Haley, N.V., III, Wright, R.A., DeVries, D.R., and Allen, M.S. 2012. Privately-owned small impoundments in central Alabama: a survey and evaluation of management techniques for largemouth bass and bluegill. North American Journal of Fisheries Management 32(6):1180-1190.
• Wright, R.A., and Kraft, C.E. 2012. Stocking strategies for recreational small impoundments. Chapter 6 in J.W. Neal and D.W. Willis (eds). Small Impoundment Management in North America. American Fisheries Society, Bethesda, Maryland. p. 155-180.