An international bottom trawl survey was designed from a European Commission´s initiative to produce biological data on the demersal resources in the Mediterranean Sea. Nine Mediterranean countries are associated in the programme, which covers all the trawlable areas along their coasts from 10 to 800 m depth. From 1994 to 2000, one survey was carried out each year, applying common standardized protocols. Seven yearly surveys have therefore been done, with a total of 7,500 stations prospected. This paper presents the methods adopted to carry out the surveys.

Marine protected areas (MPAs) require ecologically meaningful designs capable of taking into account the particularities of the species under consideration, the dynamic nature of the marine environment, and the multiplicity of anthropogenic impacts. MPAs have been most often designated to protect benthic habitats and their biota. Increasingly, there is a need to account for highly mobile pelagic taxa, such as marine birds, mammals and turtles, and their oceanic habitats. For breeding seabirds foraging from a central place, particular attention should be paid to distant foraging grounds and movement corridors, which can often extend to hundreds of kilometers from breeding colonies. We assessed the habitat use by the most threatened Mediterranean seabird, the Balearic Shearwater, Puffinus mauretanicus, using vessel-based surveys during the chick-rearing period (May-June). We used a hierarchical modeling approach to identify those environmental variables that most accurately reflected the oceanographic habitat of this species by (1) delineating its foraging range using presence/ absence data and (2) identifying important foraging grounds where it concentrates in dense aggregations. The foraging range comprised the frontal systems along the eastern Iberian continental shelf waters (depth <200 m) and areas close to the breeding colonies in the Balearic Islands. Shearwaters aggregated in productive shelf areas with elevated chlorophyll a concentrations. Following the model of a core-buffer MPA, we envisioned those areas of dense aggregation (i.e., the area of influence of the Ebro River discharge and Cape La Nao regions) as the core regions deserving elevated protection and more stringent management. More diffuse protective measures would be applied within the larger buffer region, delineated by the foraging range of the species. Marine zoning measures can greatly benefit the conservation of the Balearic Shearwater and other far-ranging seabirds by extending protective measures beyond their breeding colonies during both the breeding and non-breeding seasons.

Aim:The life history of a species is determined by trade-offs between growth, survival and reproduction to maximize fitness in a given environment. Following a theoretical model, we investigate whether the composition of marine fish communities can be understood in terms of a set of lifehistory strategies and whether the prevalence of the strategies follows specific spatial patterns that can be related to the environment.Location: European seas.Time period: 1980-2014.Major taxa studied: Fish.Methods: An extensive set of scientific bottom trawl surveys was collected to obtain the species composition of fish communities across European seas. We complemented these data with species-specific information regarding six life-history traits, reflecting reproductive, growth and feeding modes. We then calculated the optimal number of strategies needed to summarize the information contained in the traits by using archetypal analysis. The proportion of each obtained strategy in the communities and their spatial patterns were explained as a function of the environment and their temporal changes were investigated.Results: The species could be decomposed into a continuum of three life-history strategiesopportunistic, periodic and equilibrium-resulting from trade-offs between traits. The marked spatial patterns of these strategies could be explained by depth, temperature and its seasonality, chlorophyll and fishing effort. In recent years, opportunistic and equilibrium strategies significantly increased, probably due to an increase in temperature and decrease in fishing effort.Main conclusions: Our empirical analysis supports a theoretical framework outlining three lifehistory strategies of fish. The strategies vary predictably in space and time in response to the environment. This highlights the underlying process whereby fitness is optimized through trade-offs between growth, feeding and reproduction under different environmental conditions. Due to their response to the environment, life-history strategies provide a suitable tool for monitoring and understanding community changes in response to natural and anthropogenic stressors, including fishing and climate change. K E Y W O R D S archetypal analysis, community composition, depth, fecundity, life-history strategies, marine fish, offspring survival, size, temperature, trade-off, trait 812 |

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Feeding habits of blackmouth catshark Galeus melastomus and velvet belly lantern shark Etmopterus spinax were studied throughout the Spanish Mediterranean, from the Alboran Sea to the Gulf of Lion, between 400 and 790 m depth. Diets were studied taking into account size and depth differences. Included within the trophic guild of non-migratory macroplankton feeders, both species preferably exploited mesopelagic resources (mainly natantian decapods, euphausiids, mesopelagic fish and cephalopods). G. melastomus mostly preyed on decapod crustaceans (46% in terms of IRI), with cephalopods, euphausiids and mesopelagic fish as a secondary prey item. The diet of E. spinax was composed primarily of mesopelagic fish (61.4% in terms of IRI), with decapod crustaceans and cephalopods of secondary importance. Both species showed ontogenetic changes in their diets: small blackmouth catshark specimens (between 150 and 350 mm total length) mainly consumed cephalopods, medium size individuals (351-450 mm TL) consumed decapod crustaceans, while larger specimens (larger than 451 mm TL) seemed to be more generalist-feeders. Smaller specimens of E. spinax (150-250 mm TL) mostly fed on small crustaceans and cephalopods, whilst an increase in the consumption of mesopelagic fish (mycthophids and Stomiiformes) was detected in larger individuals (251-450 mm TL). Diet of G. melastomus also changed throughout the narrow depth range explored, mainly consumed euphausiids and mesopelagic fish between 400 and 500 m depth, whilst preferably exploiting natantian decapods and cephalopods below 500 m of depth. However, this trend may be correlated to the larger-deeper trend found for this species. Slight but not significant differences were found in E. spinax diet by depth, with euphausiids mainly consumed at lower depths (400-500 m). In a multispecies MDS analysis, diets of G. melastomus and E. spinax were separated and the ANOSIM ANOSIM test proved evidence for significant differences in the diets of the two species (R = 0.25; P = 0.05), mainly attributed to the stronger pelagic habits of E. spinax in comparison with G. melastomus. Low overlap (by Schoener Index) also occurred when comparing specimens of the same size range. In general, the higher occurrence of benthic prey in the diet of G. melastomus (i.e. the brachyuran crab Geryon longipes, the thalassinid shrimp Calocaris macandrae) than in E. spinax pointed to a stronger pelagic behavior for the velvet belly lantern shark. Both multivariate analysis and the Levins Index pointed to a narrow niche breadth for the two sharks. A trend of increasing fullness was found for both species in the highly productive areas of the Alboran Sea and Vera Gulf, probably related to higher resource availability, enhanced by local upwellings.