ARS | Publication request: Hatch rate of channel catfish Ictalurus punctatus (Rafinesque 1818) eggs treated with 100 mg L-1 copper sulphate pentahydrate. Aquaculture Research

Submitted to: Aquaculture Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: December 3, 2010
Publication Date: December 14, 2011
Citation: Straus, D.L., Mitchell, A.J., Carter, R.R., Steeby, J.A. 2011. Hatch rate of channel catfish Ictalurus punctatus (Rafinesque 1818) eggs treated with 100 mg L-1 copper sulphate pentahydrate. Aquaculture Research. 43:14-18.

Interpretive Summary: Catfish hatcheries use copper sulfate to prevent fungus from growing on eggs during their short incubation period. Nothing has been published about how safe it is to fish eggs. In previous studies we showed how effective it is at controlling fungus when treating eggs daily with 10 parts per million of copper sulfate. This rate is very low and copper is flushed out of the troughs within a few hours. The current research found that ten times this concentration is also very safe for eggs. This research is important to the catfish industry and will help the FDA in approving this low-cost, safe and effective compound for use in aquaculture. Current approved treatments for fungus control on catfish eggs are expensive and have human health issues. Based on current prices (August 2010) and using the lowest concentration, a typical 100 gallon hatching trough would cost $0.01 per treatment with CuSO4, but $0.45 and $0.72 per treatment with hydrogen peroxide and formalin, respectively.

Technical Abstract: Catfish hatcheries use copper sulfate (CuSO4) as an economical control for saprolegniasis on eggs. This study determines hatch rate of channel catfish eggs in hatching troughs containing 23.8°C flow-through well water when treated with 100 mg/L CuSO4 (ten times the proposed therapeutic dose). Eggs were treated daily until the embryos reached the eyed stage. Fry survival in the control and 100 mg/L CuSO4 treatments were significantly different (15 and 71%, respectively). This study demonstrates that there is a considerable margin of safety in using CuSO4 as a catfish egg treatment to control saprolegniasis.