Small-scale fishery as a driver of habitat loss in marine protected areas.

Abstract

Understanding the impacts of fisheries on the seascape is essential to prevent habitat loss. While industrial fisheries have been widely studied, the ecological effects of artisanal, or small-scale fisheries (SSFs), remain understudied, despite being one of the few extractive activities allowed within Marine Protected Areas (MPAs). This study provides one of the first comprehensive, spatially explicit estimates of habitat degradation caused by SSF in Mediterranean MPAs, integrating habitat mapping, bycatch data and fishing effort. Specifically, we assessed the effects of trammel nets on two blue carbon habitats, the seagrass Posidonia oceanica and coralligenous reefs, by comparing two well-regulated MPAs with adjacent unprotected areas. Benthic bycatch accounted on average for 41 % of the total catch by abundance and 28 % by biomass, with an annual loss of approximately 4000 m² of coralligenous habitat inside MPA and up to 6400 m² in unregulated areas. Such degradation can trigger cascading ecological effects, reducing biodiversity, altering ecosystem functioning and compromising the provision of critical ecosystem services. In contrast, impacts on Posidonia were less severe. Given the socio-cultural importance of SSFs and contributions to local well-being, there is an urgent need for broad-scale quantitative assessments of SSFs combined with fine-scale ecological data to fully capture their impacts on marine seascapes. Our results highlight the need for more sustainable fishing practices within an ecosystem-based management framework to ensure long-term habitat integrity and advance international conservation goals, including the effective expansion of multiple-use MPAs.