|Perschbacher, Peter - UAPB|
|Edzigie, Regina - UAPB|
Submitted to: University of Arkansas-Pine Bluff Aquaculture Field Day
Publication Type: Abstract Only
Publication Acceptance Date: October 7, 2004
Publication Date: October 7, 2004
Citation: Ludwig, G.M., Perschbacher, P., Edzigie, R. 2004. Effects of aerially-applied corn herbicides atrazine, rimsulfuron and nicosulfuron on the plankton communities and water quality of sunshine bass ponds [abstract]. University of Arkansas-Pine Bluff Aquaculture Field Day. p.24. Technical Abstract: Sunshine bass Morone chrysops X M. saxatilis are reared in regions with increasing acreage of fields planted in corn. The aerially-applied corn herbicide, Basis Goldtm, is composed of three herbicides: atrazine, nicosulfuron and rimsulfuron. Each was tested for possible adverse impacts on sunshine bass pond phytoplankton, zooplankton and critical water quality variables in mesocosms containing water from a sunshine bass pond. Treatments simulated direct spraying of ponds and high and low amounts of drift: 1/10 and 1/100 of direct rates respectively. Plankton and water quality samples were taken just prior to and at 24 h and 48 h after application. Field rate used for all herbicides was that of Basis Gold (0.9 kg active ingredient ha-1). Except for the atrazine, the component herbicides produced no measurable impacts. Following application photosynthesis was significantly depressed on day 2 in all atrazine treatments, but morning oxygen levels were unaffected. Un-ionized ammonia was significantly higher in the 0.01 treatment after 1 week. Morning oxygen and chlorophyll a levels increased on day 7. Of concern for fry ponds, greatest effects were noted in zooplankton. Rotifers were up to 56% lower in the drift treatments on day 2, and 80% lower on day 7. Also in drift treatments, on day 3 nauplii were up to 70% lower compared to control levels and copepods up to 25% lower. Nauplii on day 7 were higher in all treatments compared to controls, which may reflect higher chlorophyll levels.