Effects of fishery bycatch-mitigation measures on vulnerable marine fauna and target catch

Reducing fisheries bycatches of vulnerable species is critical to marine biodiversity conservation and sustainable fisheries development. Although various preventive technical measures have been implemented, their overall effects are poorly understood. Here, we used a meta-analysis approach to quantify the effects of 42 technical measures on the target catch and the bycatch of seabirds, elasmobranchs, marine mammals and sea turtles. We showed that these measures generally reduced the bycatch while having no statistically significant effect on the target catch. Sensory-based measures generally outperformed physical-based ones in reducing the bycatch. Mitigation measures that worked well for several fishing gears or taxa, although useful, were very rare. Most of the adoptions by regional fisheries management organizations (59%) were supported by our findings, although many others are yet to be robustly evaluated. Our study encourages the innovation and adoption of technical measures and provides crucial insights for policy-making and further research in sustainable bycatch management.