Assessing the contribution to overfishing of small- and large-scale fisheries in two marine regions as determined by the weight of evidence approach

Overfishing is taking place all over the world threatening marine ecosystems' health and associated livelihoods. Correctly identifying the drivers of overexploitation are crucial to guide effective fishery measures. In the present study the distinct contribution to overfishing of large-scale fisheries (LSF) and small-scale fisheries (SSF) in the Gulf of California and in the Mediterranean Sea has been compared. To accomplish the task, a weight of evidence approach has been applied based on a thorough literature review documenting overfishing. Results showed that both SSF and LSF shared responsibilities in overfishing in the two geographical locations considered, albeit with different contributions. In the Gulf of California, the weight of evidence revealed that overfishing was mainly driven by fishers engaged in SSF whereas in the Mediterranean, overfishing was mainly driven by LSF. In the Mediterranean, bycatch by LSF played a greater role than in the Gulf of California where, instead, a higher number of endemic overfished species were recorded. In order to attain fisheries sustainability some recommendations are given. In the Mediterranean, selective fishing practices and fishery policies that include input controls and catch limits are highly desirable. In the Gulf of California, the presence of governmental agencies and their services together with participatory management schemes should be reinforced in the region.