Progress 10/01/99 to 09/30/05
Outputs
The major activity was to evaluate the effects of inadvertent drift of common aerially-applied herbicides on pond ecosystems. Of 22 herbicides tested, 3 affected pond water quality: propanil, diuron and atrazine. Drift from these herbicides may reduce oxygen production and levels in ponds for several days. In this regard,diuron had the greatest impact for the longest duration (weeks). Reductions in pH and bluegreen algae abundance were beneficial, however. Intentional chemical additions in fish ponds evaluated include sodium bicarbonate for pH control and inorganic and organic fertilizer for stimulation of zooplankton abundance for fish fry nutrition. Sodium bicarbonate did not affect pH and organic fertilizer was superior to inorganic in promoting zooplankton without raising pH for fry pond management. Feed additions are the major intentional input in fish ponds, and water quality effects of feeding every day versus every other day were evaluated. Some water quality
improvements were noted with every other day feeding, but not substantial. Increased stocking rates and consequently feed rates were evaluated in terms of effect on phytoplankon levels. At the stocking and feed levels used, and present in commercial production, nutrients were judged to be in excess and thus no differences in phytoplankton were seen. Indirect approaches to controlling chemicals present and thus water quality and phytoplankton in fish ponds were investigated, such as addition of dyes (Aquashade), continuous circulation of water, and addition of filter-feeding fishes. Dyes had no significant effects, as did circulating water. Stocking the filter-feeding fish, threadfin shad, reduced undesirable bluegreen algae and stimulated other more desirable groups. However, removal of off-favor causing bluegreen species was not entirely dependable or complete and off-flavor was found in all treatments. Paddlefish were also evaluated in a preliminary study in mesocosms. Results
appeared promising, with good control of bluegreens and off-flavor algae and improvements in water quality.
Impacts
Algae-related impacts in aquaculture may incur $50 million costs from off-flavor and marketing constraints and $60 million from disease (which follows algae-flucuation induced stress, in many cases). Understanding likely algae and water quality impacts from herbicides and other treatments may aid in reducing these costs and constraints to aquaculture production efficiency and food security. On a larger scale, water-related industries such as drinking water and recreation are also affected by these algae and may also be aided by these results.
Publications
- Perschbacher, P.W. and G.M. Ludwig. 2004. Effects of diuron and other aerially applied cotton herbicides and defoliants on the plankton communities of aquaculture ponds. Aquaculture 233:197-203.
- Ludwig, G.M., M. Hobbs and P. Perschbacher. 2006. Ammonia, pH, and Plankton in Sunshine Bass Nursery Ponds: The Effect of Inorganic Fertilizer or Sodium Bicarbonate. Accepted. Journal of North American Aquaculture.
- Edziyie, R. and P. Perschbacher. 2005. Impact of propanil on a catfish and goldfish pond with surface floating phytoplankton (scum). Aquaculture America Book of Abstracts:123.
- Green, B.W., P. Perschbacher and G.M. Ludwig. 2005. Impact of threadfin shad on plankton in channel catfish production ponds. Aquaculture America Book of Abstracts:159.
- Ludwig, G.M., M.Hobbs and P. Perschbacher. 2005. Control of pH in sunshine bass fingerling ponds. Aquaculture America Book of Abstracts:253.
- Ludwig, G.M., P. Perschbacher and R. Edziyie. 2005. The effect of Basis Gold herbicide on water quality and plankton in sunshine bass fingerling ponds. Aquaculture America Book of Abstracts:252.
- Perschbacher, P. and R. Edziyie. 2005. The effects of propanil drift on culture ponds with surface floating phytoplankton (scum). World Aquaculture 2005 Book of Abstracts:489.
- Perschbacher, P. and J. Kahrs. 2005. Preliminary evaluation of paddlefish (Polyodon spathula) filtering effects on pond ecosystems. World Aquaculture 2005 Book of Abstracts:490.
- Perschbacher, P.W., G. Ludwig and R. Edziyie. 2005. Effects of propanil, diuron and atrazine on sunshine bass plankton and water quality. Aquaculture America Book of Abstracts:322.
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Progress 01/01/04 to 12/31/04
Outputs
Atrazine herbicide drift effects on plankton and water quality were repeated after previous year's work showed impacts on zooplankton, which are important natural food of fish fry and plankton-feeding fish such as minnows. Atrazine in Basis Gold herbicide, used for postemergent corn weed control, was applied to mesocosms filled with water from a fry pond. Drift rates were tested in triplicate before and after addition. Unlike the previous year' results in sunshine bass culture pond water, fry pond water zooplankton were not negatively impacted by herbicide addition. Although this is a positive finding, the difference between the two studies is unexplained and will be further investigated. The effect on phytoplankton communities of four stocking levels of channel catfish was evaluated. Although there were significant differences in off-flavor algae and composition of algae on several dates, no trend was observed.
Impacts
Agriculturists, whether fish farmers or herbicide applicators, may not expect harmful impacts from expected drift levels of atrazine in Basis Gold corn herbicide to fry ponds. Further confirmation is needed however. No correlation was found between increasing stocking levels of channel catfish and off-flavor and undesirable bluegreen algae levels. This indicates nutrients were sufficient at the lowest level of stocking and thus feeding to develop the characteristic off-flavor algae species and dominance by bluegreen algae.
Publications
- Perschbacher, P.W. 2005. Effects of temperature on the acute toxicity of copper sulfate to juvenile channel catfish Ictalurus punctatus. Aquaculture 233:197-203.
- Ludwig, G.M., R. Edziyie and P. Perschbacher. 2004. Mesocosm testing of Basis Gold herbicide for effects on sunshine bass culture ponds. Book of Abstracts, Aquaculture 2004:363.
- Perschbacher, P.W. 2003. Evaluation of an intensive polyculture system incorporating control of algal off-flavors and water quality. p. 231-236. In: B. Phillips, B.A. Megrey and Y. Zhou (eds). Proceeding of the Third World Fisheries Congress: Feeding the World with Fish in the Next Millenium-the Balance between Production and Environment. American Fisheries Society Symposium 38, Bethseda, MD.
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Progress 01/01/03 to 12/31/03
Outputs
Basis Gold, the major aerially-applied corn herbicide, was evaluated for drift impacts on plankton and water quality in experimental mesocosms with hybrid striped bass fish pond water. Rimsulfuron and nicosulfuron did not produce any impacts. The other component of Basis Gold, atrazine, significantly reduced oxygen production at drift rates 48 h after application. No reduction in morning dissolved oxygen levels were noted, however. Thus, atrazine impact from drift on fish pond plankton and water quality does not pose a significant biological risk to adjacent fish ponds. Water quality was compared every week in channel catfish experimental ponds receiving three protein levels and every day versus every other day feeding. Total ammonia-nitrogen, dissolved oxygen and nitrite-nitrogen levels were adversely impacted on several sample dates by every day feeding with 32% protein levels compared to every other day feeding with 28, 32 and 36% protein levels.
Impacts
Agriculturists, whether fish farmers or herbicide applicators, should not expect harmful impacts from expected drift levels of atrazine to plankton communities and water quality of adjacent fish ponds. In terms of water quality, feeding cultured catfish every other day was somewhat beneficial.
Publications
- Perschbacher, P., G. Ludwig and H. Thomforde. 2003. Potential effects of diuron drift as an aerially-applied cotton herbicide on fish pond plankton and water quality. Catfish Farmers of America Research Symposium Book of Abstracts. p.47.
- Perschbacher, P., G. Ludwig and H. Thomforde. 2003. Effects of aerially-applied cotton herbicides, including diuron, on fish pond plankton. Aquaculture America Book of Abstracts. p. 226.
- Ludwig, G.M., P. Perschbacher and H. Thomforde. 2003. Effects on fish pond plankton of aerially-applied diuron and other cotton herbicides. World Aquaculture 2003 Book of Abstracts. p. 428.
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Progress 01/01/02 to 12/31/02
Outputs
Seven, aerially-applied cotton herbicides were tested for possible adverse affects from drift on fish pond plankton and water quality. Tests used fish pond water and were conducted in 145-gallon outdoor tank mesocosms. Rates were 1% and 10% of the recommended field application rate and represented low and high drift rates expected. Commercial compounds tested were diuron, paraquat, quizalofop and the defoliants dimethipin, tribufos, ethephon and sodium chlorate. Only diuron produced any measurable impacts. Diuron reduced oxygen production in relation to dose and resulted in critical morning oxygen levels after 1 week in the high dift rate and slowly returned to control levels by week 3. Positive effects were elimination of odor-causing bluegreen phytoplankton algae and stimulation of green phytoplankton algae. Diuron may be applied to cotton fields in the spring as a burndown and in the fall as a defoliant. Defoliant rates are approximately 1/10 the spring rate of 0.2
ppm.
Impacts
Effects from drift of cotton herbicides on water quality is quantified. Diuron was the only herbicide to show impacts, and findings may be used by applicators to reduce drift and thus any possible adverse impacts.
Publications
- Perschbacher, P., G.M. Ludwig and N. Slaton. 2002. Effects of common aerially-applied rice herbicides on the plankton communities of aquaculture ponds. Aquaculture 214:241-246.
- Perschbacher, P., G. Ludwig and H. Thomforde. 2002. Effects of aerially-applied cotton herbicides, including diuron, on fish pond plankton and water quality. Book of Abstracts, UAPB Aquaculture/Fisheries Field Day.
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Progress 01/01/01 to 12/31/01
Outputs
Four rice herbicides, aerially-applied in spring, were evaluated for simulated drift effects on fish pond plankton and water quality. Four rates of each herbicide were tested in 500-l tanks filled with fish pond water: direct application, low and high drift (1% and 10% of direct) and a control with no herbicide. Clomazone, pendamethalin, and two treatments of dry formulation propanil (intial dose and second dose one week later)were tested. Inital dose propanil at the highest rate (equivalent to direct or overspraying) inhibited phytoplankton primary productivity and led to stressful dissolved oxygen levels 48 h after application and continuing for 48 h. Chlorophyll levels however increased 24 h after application in response to the level of propanil added. The second dose of propanil one week following the intial dose failed to depress oxygen levels, but resulted in increased chlorophyll and zooplankton counts-apparently in response to the increased algal biomass. With
the seven rice herbicides evaluated in 2001, the assessment of common aerially-applied rice herbicides is completed and drift concentrations of rice herbicides do not appear to be harmful to fish pond plankton and water quality. Propanil will be further evaluated in 2002 and cotton herbicides.
Impacts
Fish farmers should not see adverse impacts on pond plankton and water quality from drift concentrations of rice herbicides. However, direct spraying of propanil will result in stressful low oxygen levels for 48 h.
Publications
- No publications reported this period
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Progress 01/01/00 to 12/31/00
Outputs
A new mesocosm facility was completed for the 2000 tests. Common rice herbicides applied by air during the months of June and July were tested for adverse impacts on fish pond water quality and plankton communities. Herbicides were applied to the mesocosm pools at recommended field rates (overspray), and drift rates of 10% and 1% of the field rate. Water quality measurements were made prior to application and at 24h and 48h after application. Herbicides tested in sequence were thiobencarb, quinclorac, halosulfuron, bensulfuron methyl, triclopyr, 2,4-D amine, and molinate. No measurable impact was noted from any test. An additional four rice herbicides will be tested.
Impacts
Fish farmers and rice farmers will now be able to assess impacts of using these herbicides on pond water quality and discount their impact on any water quality problems arising during aerial applications.
Publications
- Perschbacher, P., J. White, M. Miller, G. Ludwig and N. Slaton. 2001. Effects of rice herbicides, aerially-applied midseason, on fish pond water quality. Book of Abstracts, World Aquaculture Society Annual Meeting Orlando, FL, p.523.
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Progress 01/01/99 to 12/31/99
Outputs
No findings to date. Testing will begin Spring 2000. Preparations are continuing and Extension personnel are being contacted re. rice herbicides and fungicides that are aerially applied and thus could impact fish ponds.
Impacts
(N/A)
Publications
- No publications reported this period
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