Omnidirectional sonar increases catch efficiency in a pelagic sportfishing tournament

Abstract Technological advances in fisheries often lead to increased catch efficiency, which has the potential to cause overexploitation. One popular and emerging technology in pelagic sportfishing is omnidirectional sonar, which can be used to identify and target individual fish. We analyzed catch data from two consecutive years of a sportfishing tournament in North Carolina, USA to investigate differences in catch success between vessels with omnidirectional sonar and those without it. In this tournament, vessels target six pelagic species, including three Istiophorid billfishes, dolphinfish Coryphaena hippurus, wahoo Acanthocybium solandri, and yellowfin tuna Thunnus albacares. A Bayesian generalized linear model of combined-billfish-species catch rates revealed that vessels with sonar caught 84% (95% credible interval: 42%–136%) more fish than vessels without sonar, when accounting for vessel-specific variation and interannual differences. A Fisher’s exact test revealed that the numerical catch of prize-winning (by weight) non-billfish species differed by sonar presence, with sonar-equipped vessels winning more than the expected number of prizes. The finding that boats with omnidirectional sonar have higher catch rates for these pelagic species has implications for fishery managers aiming to ensure the sustainability of pelagic stocks in the face of emerging technologies.