|Perscbacher, Peter - UAPB|
Submitted to: Journal of Applied Aquaculture
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: November 15, 2005
Publication Date: June 15, 2007
Citation: Perscbacher, P., Ludwig, G.M. 2007. High draft rate effects of propanil and basis gold on the plankton communites and water quality of a prestocking sunshine bass Morone chrysops X M. isaxatilis, fry pond. Journal of Applied Aquaculture. 19(2):101-112. Interpretive Summary: Fingerling sunshine bass production depends upon the presence of sufficient zooplankton in their culture ponds to provide food for the young fish to survive and grow. Zooplankton feeds on tiny plants called phytoplankton. The proximity of fingerling production ponds to row crops that are subjected to aerial spraying with herbicides suggests that there is some risk that herbicide drift will damage the food support system in the ponds. This experiment determined the effect of two widely used herbicides, propanil and Basis Gold (86.8% atrazine) at projected aerial drift levels on fingerling production pond water quality, phytoplankton and zooplankton populations. Results for propanil indicated minor, initial depression of phytoplankton productivity and several days of slightly diminished dissolved oxygen concentrations. Basis Gold also reduced dissolved oxygen but not net primary productivity. Propanil lowered some cyanobacteria and stimulated green algae while Basis Gold increased diatom presence. Zooplankton was not adversely affected by the herbicides. Since effects of the herbicides were minor and very short lived, effects on sunshine bass production should be minimal, although monitoring of pond dissolved oxygen levels is recommended following nearby aerial spraying of these herbicides.
Technical Abstract: Effects on fry-pond phytoplankton, zooplankton and water quality from propanil and Basis Gold (86.8% atrazine) herbicides were evaluated at 30% of field application rates in. The study was conducted in 12, 500-l outdoor pool mesocosms, filled with pond water from an adjacent 0.1-ha pond fertilized and prepared as recommended for sunshine bass, Morone chrysops X M. saxatilis, fry stocking. Plankton and water quality samples were taken just prior to application (day 0) and day 1, 2, 3, 4-zooplankton only and 7 after application. Field application rates for Basis Gold and propanil were 0.8 kg and 1.80 kg/ha active ingredient respectively. Following application, net primary productivity was significantly depressed on day 1 in the propanil treatments, but increased on days 2 and 3. Morning oxygen (0900) was lower on days 1-3, but not to critical levels. Also in the presence of propanil, pH and consequently UIA were lower from day 1-3. Basis Gold reduced morning DO on day 2 and 3, but not net primary productivity. Nitrite-N was significantly higher on day 1. Phytoplankton total numbers, primarily composed of the cyanobacterium Chroococcus sp., were lowered by propanil on days 1, 2 and 3, and similarly affected by Basis Gold on days 2 and 3. Numbers of green algae, Scenedesmus sp. and Coelastrum sp., and diatoms were however stimulated by propanil and diatoms by Basis Gold. Thus effects from high levels of drift from propanil and Basis Gold should not result in negative impacts on fry production.