|Straus, David - Dave|
|Ledbetter, Cynthia - Cindy|
|HEIKES, DAVID - Dunn’s Fish Farms Of Arkansas, Inc|
Submitted to: North American Journal of Aquaculture
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/4/2023
Publication Date: 3/6/2023
Citation: Straus, D.L., Ledbetter, C.K., Farmer, B.D., Deshotel, M.B., Heikes, D.L. 2023. Toxicity of copper sulfate to largemouth bass fry in naturally soft water. North American Journal of Aquaculture. 85(2):174-177. https://doi.org/10.1002/naaq.10284.
Interpretive Summary: Copper sulfate is used in aquaculture for fungus control on fish eggs; fungus can prevent the eggs from hatching. It works well and is cheap to use for farmers with moderate or high alkalinity/hardness waters, but we didn't know how toxic it is in soft (lower alkalinity/hardness) waters. We determined the acute toxicity of copper sulfate to freshly hatched largemouth bass in naturally soft water and found the concentration that farmers can treat with and not kill the baby fish. This will help the farmers produce more fish in their hatchery.
Technical Abstract: Use of copper sulfate pentahydrate (herein designated CuSO4) for fungus control on fish embryos is extremely effective and economical for farmers in waters with moderate or high alkalinity/hardness; however, fry toxicity in low alkalinity/hardness waters is a concern. In the present study, the acute toxicity of CuSO4 to largemouth bass (LMB; Micropterus salmoides) in naturally soft water (i.e., 42 mg/L alkalinity, 41 mg/L hardness) was determined. Median lethal concentration (LC50) values at 24 h were 3.97 mg/L CuSO4 for yolk-sac fry and 5.24 mg/L CuSO4 for swim-up fry. Most importantly for farmers, the No Observed Effect Concentrations (NOEC) in the present study was 0.625 mg/L CuSO4 for both stages of fry. This research was done in order to demonstrate the safe use of CuSO4 for fungus control on LMB embryos in soft water.