PearlNet performance: Catch efficiency and practicality of a potential odontocete bycatch reduction tool in set net fisheries

Abstract

Incidental capture in fishing gear, especially in bottom set nets, represents a significant cause of mortality for odontocete worldwide. Given that these species depend on echolocation for spatial orientation and prey detection, the PearlNet aims to mitigate this impact by enhancing the acoustic visibility of nets through the incorporation of small acrylic glass spheres in standard nets. This modification can potentially enable odontocetes to recognize them as a physical barrier, which may lower the risk of unintended interactions. However, for mitigation measures to be implemented in commercial fisheries, they must not compromise fishing performance. This study aimed to evaluate the PearlNet’s relative catch efficiency on fish species and handling time in a commercial fishery in the Baltic Sea. Plaice and flounder were the most abundant species caught during the trials. The catch efficiency of the PearlNet relative to standard nets for these species was, respectively, 106.49% (95% CI: 99.72–113.84) and 101.08% (95% CI: 94.33–110.40), revealing similar catch efficiency between gears. Furthermore, the PearlNet did not affect the handling time of the gear. These results confirm the feasibility of using PearlNets, which will facilitate future studies evaluating the effectiveness of PearlNet in reducing odontocete bycatch in commercial fisheries.