This study evaluates the fishing pressure exerted by the most common recreational and professional, small-scale fishing practices on vulnerable target and bycatch species in coastal and offshore waters of the western Mediterranean. By combining multiple data sources, we assembled a unique dataset on catches at multiple sites in these areas by recreational (RF) and small-scale fisheries (SSF), covering the period from 1997 to 2015. Furthermore, a framework with which to identify the vulnerable species among all the species caught is provided; it is based on the IUCN Red List, international conventions for the protection of flora and fauna, the Habitats Directive and the intrinsic vulnerability index of marine fish. Overall, about a quarter of exploited species targeted by SSF and RF in coastal waters were vulnerable, making up nearly 50% of the total SSF catch and nearly 20% of the total recreational catch. In offshore waters, 100% of the RF and SSF catch was made up of vulnerable species. Among the species caught as bycatch in both areas by SSF and RF, there was a total of 27 vulnerable vertebrate species, which included birds, cetaceans, elasmobranchs and sea turtles. Our results highlight the need to differentiate between different fishing methods or gears when studying the fishing impacts on vulnerable species. The results also indicate that, although RF and SSF are often considered to have a relatively low ecological impact, a range of different fishing methods are affecting vulnerable species in coastal or offshore waters in the western Mediterranean Sea, be they targeted or taken unintentionally as bycatch.
29The flow of non-living carbon (detritus) is considered an important process because it 30 connects ecosystems and fuels benthic communities. In Norwegian kelp forests, 90% 31 of the kelp production is exported to adjacent ecosystems where it can play a 32 significant role in shaping benthic communities. We quantified the major structural and 33 functional traits of an Arctic deep-sea ecosystem associated with kelp exports and 34 assessed the ecological role of kelp export into the deep-sea system. We first 35 developed a food-web model using the Ecopath with Ecosim (EwE) approach to 36 represent the state of the deep (450 m) ecosystem of the Malangen fjord (Northern 37 Norway) in 2017. Subsequently, we used the temporal dynamic model Ecosim to 38 explore the structure and functioning traits of a theoretical deep-sea ecosystem 39 projecting a decrease of kelp detritus biomass reaching the deep-sea ecosystem. 40Overall, our findings reveal that kelp detritus from shallow coastal areas has a small but 41 noticeable role structuring the deep-sea ecosystem of Malangen. The temporal 42 simulations show important differences depending on the application of mediating 43 effects, which allow considering the detritus as a mediating group in prey-predator 44interaction, in addition to its direct role in trophic relationships. When mediating effects 45 are applied, biomass increases for benthopelagic shrimps and suprabenthos groups 46 and decreases for rays and skates, velvet belly, rabbitfish and other commercial 47 demersal fishes under the low kelp detritus scenarios. Biomass-based and trophic-48 based indicators reveal a noticeable impact on the deep-sea ecosystem structure due 49 to depletion of kelp detritus. To further assess future changes of the Arctic deep-sea 50 ecosystems, dependencies with adjacent ecosystems, such as kelp detritus production, 51 should be included. 52
Information on the spatial patterns and habitat preferences of marine species is key to understand the functioning of marine ecosystem and to manage and protect marine resources efficiently. However, the study of spatial patterns of marine ecosystems is challenging because they are dynamic environments that can vary seasonally. We modelled the spatial patterns of abundance, biomass, and biodiversity in a demersal community of the northwestern Mediterranean Sea by season using hierarchical Bayesian spatial models and environmental, physical, and anthropogenic factors. Overall, our findings revealed the importance of seasonality in the spatial patterns of the demersal community, which were mainly driven by sea surface temperature. Results also underlined important patterns of movements of demersal organisms: fishes, cephalopods, and crustaceans showed high densities in the area surrounding the Ebro Delta River in winter mainly driven by species-specific behaviour. Our results are relevant to inform future management measures in the study area, such as seasonal fishing restrictions, or to adapt local marine protected areas to seasonal processes. This study provides evidence of the need to expand current monitoring schemes to capture the seasonality of marine demersal communities for a more comprehensive marine spatial planning framework.
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