Submitted to: Book of Abstracts Aquaculture America
Publication Type: Abstract only
Publication Acceptance Date: 10/6/2004
Publication Date: 9/18/2004
Citation: Ludwig, G.M., Perschbacher, P., Egzigie, R. 2004. The effects of Basis Gold herbicide on water quality and plankton in sunshine bass fingerling production ponds [abstract]. Book of Abstracts, Aquaculture America. p. 252. Interpretive Summary:
Technical Abstract: Production of sunshine bass fingerlings in ponds depends upon the presence of high densities of zooplankton that rely on phytoplankton resources in the ponds. Fingerling culture ponds are often adjacent to row crop fields that require the use of herbicides for weed control. In the Mississippi Alluvial Plain (the 'Delta') many of the herbicides are applied by aerial spraying from fixed-wing planes. As a result, the potential for damage to sunshine bass culture ponds from drift of herbicides used in corn farming has increased. Basis Gold' is the trade name of the herbicide most commonly used on corn. We determined the effects of the herbicide on water quality and plankton densities at herbicide concentrations equal to a direct application (equivalent to 0.79 lb/ha active ingredient), and at 1/10th and 1/100th of that amount to simulate aerial drift. Tests were conducted in 500 liter mesocosms filled with water from a pond prepared for fingerling sunshine bass production. Basis Gold' had a significant but small effect on several water quality variables and zooplankton densities. Dissolved oxygen levels were reduced in the full treatment by 24 hrs, in all treatments by 72 hr, but were not different from the control by the next measurement at 216 hours (9 days). The pH in the full treatment was slightly reduced in the full treatment and remained that way until the last sampling at 336 hours (14 days) after application. Unionized ammonia was also slightly reduced in the full treatment at 216 and 336 hr after application. Although photosynthesis was affected, no change in the amount of chlorophyll a was detected. Zooplankton population densities were not affected during the first three days but by one week after application copepod densities were decreased while cladoceran densities increased in direct relationship to the amount of Basis Gold' applied. Two days later all zooplankton populations were similar. Although the corn herbicide Basis Gold' had significant effects on sunshine bass fingerling production pond water quality and plankton, none of the effects appeared to be adequate to cause an adverse effect on fingerling health or production.