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  • Reserve effect of a small North-East Atlantic marine protected area (Arrabida, Portugal) on soft-sediment fish species
    Publication . Martínez Ramírez, Lucas; Priester, Carl Robert; Sousa, Inês; Erzini, Karim; Abecasis, David
    The implementation of marine protected areas (MPAs) has been widely used as a tool to manage and conserve marine resources and services. Yet, to date, the reserve effect is still weakly evaluated, particularly for soft-sediment habitats. The Arrabida MPA, considered as a biodiversity hotspot, was fully established in 2009 on the west coast of Portugal and is characterized by large expanses of soft-sediment habitats. This MPA was established to protect biodiversity and to ensure the livelihood of the local small-scale fisheries community. Beyond before-after-control-impact (BACI) analyses were carried out on catch data (abundance and biomass) of 351 trammel net sets from experimental fishing campaigns (2007-2019) to study the reserve effect on demersal fish populations. The results show a declining trend in abundance inside and outside the protected area, with significant positive effects only found for undersize commercial species and Solea senegalensis, and a general increase in fish species total length. Despite the lack of any obvious reserve effect, the increase in fish length can be considered as a first sign. Anthropogenic pressures are generalized around the area, and transgressions of the restrictions are frequently observed inside the no-take zone. These can, among other aspects, delay or prevent the expected reserve effects. Therefore, enforcement and/or modification of the spatial plan must be incentivized to achieve the goals of the MPA.
  • Tagging mortality in acoustic telemetry studies: insights from a multispecies analysis
    Publication . Martínez Ramírez, Lucas; Bentes, Luis; Dias Almeida Cardoso, André Filipe; Erzini, Karim; Gandra, Miguel; Kraft, Sebastian; Winkler, Alexander; Abecasis, David
    The widespread adoption of acoustic telemetry has transformed our understanding of marine species' behavior and movement ecology. However, accurately interpreting telemetry data, especially concerning tagging mortality, is essential for drawing valid conclusions. In this study, we scrutinized tagging mortality in 223 individuals across 14 species and evaluated the impact of tagging methodologies, including capture method and size effects. Results reveal high tagging survival rates overall, attributable to the resiliency of the studied species and the rigorous animal welfare protocols followed during tagging procedures. Our results highlight the importance of tailoring array designs to the specific mobility patterns of the studied species for accurate survival assessments. This research contributes to generalizing mortality assessments and clearing the path for more precise and reliable telemetry studies in the future.