Development and Efficacy of a Bycatch Reduction Device for Wisconsin-Type Fyke Nets Deployed in Freshwater Systems

Abstract

Aquatic biologists throughout the United States use fyke nets to sample fish. Often, these nets have high turtle bycatch and mortality rates, especially when set in extreme environmental conditions. Because a previous study found increased turtle mortality using Wisconsin-type fyke nets, we designed and tested a bycatch reduction device (BRD) for this net type and investigated its ability to reduce turtle bycatch without affecting fish capture. Over 68 net-nights, the BRD significantly reduced turtle bycatch with no significant decrease in fish quantity or richness when compared to a control fyke net with no BRD. We argue that aquatic biologists and managers should consider turtle mortality when sampling fishes and other aquatic organisms. We also suggest that further studies be conducted to develop BRDs for all passive freshwater sampling nets. Further, BRDs that have already been designed and tested and appear effective at reducing turtle bycatch without significantly affecting fish catch, such as ours, should be implemented in freshwater fisheries methodologies. This is the first known BRD developed for freshwater trap nets.