Submitted to: Book of Abstracts World Aquaculture Society
Publication Type: Abstract Only
Publication Acceptance Date: 1/15/2006
Publication Date: 5/24/2006
Citation: Perschbacher, P.W., Ludwig, G.M. 2006. Evaluation of propanil and atrazine high drift impacts on fry pond plankton and water quality [abstract]. Book of Abstracts, World Aquaculture Society. Paper No. 813. p. 731. Interpretive Summary: Frequently aquaculture production ponds (averaging 7 ha) are adjacent to row crop fields. Impacts of herbicide drift at up to 20% of the direct application rates of 29 aerially-applied herbicides on production pond plankton and water quality have been evaluated in 500 L outdoor mesocosms over the span of 10 years. Only Propanil, used on rice, atrazine, used on corn, and diuron, used on cotton produced negative impacts on the ponds. Smaller fry ponds could could receive higher drift levels. When Propanil and Basis gold (87% atrazine) were applied at 30% of field rates to pond water that had been prepared for fingerling culture several effects were found. There was a lower net primary productivity rate (less oxygen produced by plants), lower morning dissolved oxygen level and lower population levels of some bluegreen algae. Lower pH and less unionized ammonia and enhanced green algae and diatom level were also found. Few differences in zooplankton levels were found. Overall, the detrimental effects of the herbicides were probably too small and lasted for too short of time to reduce fingerling fish production.
Technical Abstract: Aquaculture production ponds (averaging 7 ha) are often adjacent to fields of row crops. Impacts of drift at up to 20% of field rates of 29 aerially-applied herbicides on production plakton and water quality were evaluated in 500-L outdoor mesocosms over the span of 10b years. Propanil (rice), atrazine (corn) anddiuron (cotton) produced negative impacts. Smaller ponds (1 ha) could receive higher dirft levels. Ten water quality parameters were evaluated after the frequently-used herbicides propanil and Basis Gold (87% atrazine) were applied at 30% of field rates to pond water pumped into triplicate mesocosms after fertilization prior to fry stocking. The result was lower net primary productivity, morning Dissolved and some cyanobacteria (Chroococcus) levels. Levels reached were not expected to negatively impact fish fry. Lower pH and consequently ammonia and enhanced green algae and diatom populations may be beneficial to fry. Little effect on zooplankton or chlorophyll was found. Although these herbicides have measurable effects, the effects are short lasting and usually of little consequence.