Prevention of the Spread of Zebra Mussels during Fish Hatchery and Aquaculture Activities

Abstract

Abstract Fish hatchery and aquaculture activities present numerous opportunities for accelerating the spread of zebra mussels Dreissena polymorpha to new locations. We tested aquaculture chemicals including NaCl, KCl, CaCl2, formalin, and the lampricide TFM (3-trifluoromethyl-4-nitrophenol) for efficacy against zebra mussel veligers and tolerance by several species of juvenile fish. Our short-term exposures simulated the high-stress environment of fish transport. High concentration of NaCl was the most effective treatment against veligers but also caused unacceptably high mortality in most fish species. A dilute solution of formalin (25 mg/L) in conjunction with KCl was effective against veligers and was safe for all fish taxa tested. However, concurrent exposures to 5,000 mg NaCl/L, which is commonly used to counteract fish shock during transport, decreased the toxicity of the formalin to veligers.