SUMMARY: The feeding ecology of eight demersal elasmobranchs, three sharks (Etmopterus spinax, Scyliorhinus canicula and Galeus melastomus) and five batoids (Myliobatis aquila, Leucoraja naevus, Raja polystigma, R. miraletus and R. clavata), from the Balearic Sea (western Mediterranean) was analyzed. For each species, the diet and feeding habits were characterized by depth strata using quantitative indices such as diet overlap, diet breadth and prey diversity. Diet variation with size and depth were also tested for the most abundant species. For shelf-living species, natantian and reptantian crustaceans together with teleosts were the most important preys. On slope bottoms, euphausiids were the preferential prey for S. canicula and G. melastomus, while E. spinax fed mainly on cephalopods. The most specialist and generalist diet corresponded to G. melastomus living on the upper slope and S. canicula from the continental shelf, respectively. High overlap was found between all the skates on the continental shelf and the sympatric sharks S. canicula and G. melastomus on the slope. Significant overlap was also found between S. canicula and R. clavata on the continental shelf. Size was found to significantly affect the diet of S. canicula, G. melastomus and R. clavata, whereas depth affected exclusively S. canicula.Keywords: Elasmobranch, batoid, shark, feeding habits, diet overlap, niche breadth, Mediterranean. RESUMEN: Ecología alimentaria de elasmobranquios demersales de plataforma y talud en aguas de las Islas Baleares (Mediterráneo Occidental). -Se estudia la ecología alimentaria de ocho elasmobranquios demersales, tres tiburones (Etmopterus spinax, Scyliorhinus canicula y Galeus melastomus) y cinco rayas (Myliobatis aquila, Leucoraja naevus, Raja polystigma, R. miraletus y R. clavata), del mar Balear (Mediterráneo Occidental). Para cada especie se caracterizó la dieta y la estrategia alimentaria por estratos de profundidad mediante diferentes índices cuantitativos. También se analizó la variación intraespecífica de la dieta con la talla y la profundidad en las especies más abundantes. Las presas más frecuentes en especies de la plataforma continental fueron los peces y los crustáceos natantia y reptantia. En aguas del talud las presas principales de S. canicula y G. melastomus fueron los eufausiáceos, mientras que E. spinax consumió preferentemente cefalópodos. Las especies con la dieta más especializada y más generalista fueron G. melastomus del talud superior y S. canicula de la plataforma costera, respectivamente. En aguas de la plataforma se detectó solapamiento de dieta entre todas las especies de batoideos, así como entre S. canicula y R. clavata; el solapamiento fue significativo también entre S. canicula y G. melastomus del talud. Se observaron cambios ontogénicos en la dieta de S. canicula, G. melastomus y R. clavata, mientras que la única especie que mostró cambios de dieta con la profundidad fue S. canicula.Palabras clave: elasmobranquio, batoideo, tiburón, estrategia alimentaria, solapamiento de die...

Selectivity studies usually describe the effects on target species, whereas information on by-catch and discards is scarce. Nevertheless, large quantities of undersized individuals and invertebrates are discarded in the Mediterranean multi-species bottom trawl fishery. The present work analyses the data from two surveys carried out on the shallow and deep continental shelf (50-78 m, and 147-189 m, respectively) off the Balearic Islands (western Mediterranean). In these surveys, the traditionally used 40 mm diamond mesh codend and an experimental square mesh codend were used under commercial conditions. Catch composition, yields, size selectivity of both target and by-catch species, and discards were compared between the two mesh types. The mean selection length (L 50 ) clearly increased for most species when using square mesh, escaping many more individuals under their minimum landing size. Yield of Spicara smaris was significantly lower by using the square mesh, changing the composition of the retained catch. Escapement ratio and economic loss were significantly higher with square mesh, although economic loss was almost negligible for both meshes on the deep continental shelf. The use of square mesh significantly reduced the discards of algae in the shallow waters and fish on the deep continental shelf. The results confirmed that square mesh codend reduces the fishing pressure on small specimens as well as the impact of trawling on the ecosystem. These benefits would not lead to a reduction of the yields neither of the main target species, the fishes Merluccius merluccius, Mullus surmuletus, Zeus faber, and the cephalopods Loligo vulgaris and Octopus vulgaris, nor of the rest of commercial categories, except for Spicara smaris.

Menorca Channel (Balearic Islands, western Mediterranean) comprises 98,700 Ha of continental shelf. It has been proposed to include this area in the Natura 2000 network due to the wide range of species and habitats of high conservation value found here, such as Posidonia oceanica meadows and maërl and coralligenous beds. This study aimed to establish a scientific basis for managing and protecting the continental shelf bottoms in Menorca Channel. Sampling was carried out with side-scan sonar, beam trawls, box corers, a remote-operated vehicle and an underwater drop camera. The information collected was used to map the habitat distribution between 50 and 100 m depth, as well as make an inventory and describe the spatial patterns of both the specific and functional diversity. A total of 636 species was recorded in a mosaic of habitats in which Corallinacea calcareous algae and other soft red algae (Osmundaria volubilis and Peyssonnelia spp.) were the most abundant groups. Hotspots of specific and functional diversity were located in areas with high habitat heterogeneity and complexity. Protection of Menorca Channel should not only include the habitats and species in the European directives, but also the habitats that are not currently protected, such as O. volubilis and Peyssonnelia beds, due to Electronic supplementary material The online version of this article (

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Quetglas, A., Ordines, F., Hidalgo, M., Monserrat, S., Ruiz, S., Amores, Á., Moranta, J., and Massutí, E. 2013. Synchronous combined effects of fishing and climate within a demersal community. – ICES Journal of Marine Science, 70: 319–328. Accumulating evidence shows that fishing exploitation and environmental variables can synergistically affect the population dynamics of exploited populations. Here, we document an interaction between fishing impact and climate variability that triggered a synchronic response in the population fluctuations of six exploited species in the Mediterranean from 1965–2008. Throughout this period, the fishing activity experienced a sharp increase in fishing effort, which caused all stocks to shift from an early period of underexploitation to a later period of overexploitation. This change altered the population resilience of the stocks and brought about an increase in the sensitivity of its dynamics to climate variability. Landings increased exponentially when underexploited but displayed an oscillatory behaviour once overexploited. Climatic indices, related to the Mediterranean mesoscale hydrography and large-scale north Atlantic climatic variability, seemed to affect the species with broader age structure and longer lifespan, while the global-scale El Niño Southern Oscillation index (ENSO) positively influenced the population abundances of species with a narrow age structure and short lifespan. The species affected by ENSO preferentially inhabit the continental shelf, suggesting that Mediterranean shelf ecosystems are sensitive to the hydroclimatic variability linked to global climate.

The present study confirms the presence of the Norwegian skate Dipturus nidarosiensis (Storm, 1881) (Stehmann et al., 2015).

Chondrichthyans are a vulnerable group that has been overexploited for almost half a century in the Mediterranean. Since in this area most chondrichthyans are rarely incorporated into international statistics, the impact of fishing on their populations is difficult to assess. Here, we evaluate temporal trends in order to understand the recent history of chondrichthyans in the western Mediterranean. Fishery-independent data were obtained from scientific surveys carried out from 1994 to 2015 in three geographical sub-areas. Our results reflect fairly stable populations in terms of diversity, with some increase in density and standardized biomass of some species dwelling on the continental shelf, and even for some species dwelling on the slope. In contrast, decreasing trends were observed in some deep-water species. This can be explained by the reduction of the trawling effort on the continental shelf over the last few decades, and the shift of the fleet towards deep waters, along with the greater resilience displayed by some species. Furthermore, a decreasing trend in maturity of Scyliorhinus canicula was detected, suggesting an evolutionary response to overfishing. These results improve scientific knowledge for developing true adaptive management in the Mediterranean that will implement measures to strengthen or initiate the recovery of chondrichthyans. Marine ecosystems are under pressure from overfishing, habitat degradation and climate change which have altered the populations of most of their species 1,2 , especially chondrichthyans (sharks, rays and chimaeras), due to their low population resilience 3-5. Global chondrichthyan landings, reported to the Food and Agriculture Organization of the United Nations (FAO), increased over 200% from 1950 to the peak year in 2003 and subsequently dropped almost 15% by 2011 6. In the Mediterranean, the temporal evolution of chondrichthyan landings has gone through three stages: a development phase at the beginning of the 1950s; followed by intense fishing pressure from the mid 1950s to 1970, corresponding to the exploited phase; and a decreasing trend from 1970 to recent years, indicating an overexploited status (Fig. 1), such as has been reported for most demersal and pelagic bony fish and shellfish stocks a decade later during the eighties 7-10. This earlier overexploitation in chondrichthyans is to be expected due to their low resilience. Studies of long time series of chondrichthyan catches conducted in several areas of the Mediterranean have also shown decreasing trends over the last few decades 11-14. Furthermore, there is evidence that Mediterranean chondrichthyans have declined in diversity. At present, several species such as Dipturus batis (recently split into two cryptic species, D. cf. flossada and D. cf. intermedia 15 , Pristis

A new miniature gobiid species, Buenia massutii sp. nov. (Teleostei: Gobiidae) is described from the circalittoral bottom off the Balearic Islands, western Mediterranean. Phylogenetic analysis of the mitochondrial COI-barcoding fragment supports its species-level distinctiveness and the monophyly of the genus Buenia. A description and diagnosis of the genus Buenia is for the first time provided. Material of the new species was collected in 57-67 m depth from beam trawl samples carried out on red algae beds. The traits that differentiate the new species from two congeneric species are: anterior oculoscapular canal only semiclosed with pores σ, λ, κ, ω, α, ρ and additional pores and open furrows from interorbital part to pore ρ; posterior oculoscapular canal absent; suborbital row c with 5 papillae; scales in lateral series 26-28; pectoral fin rays 16; the second spine of the first dorsal fin the longest, reaching to or behind posterior end of the second dorsal fin in males when folded down; pelvic fin anterior membrane one sixth or less of length of spinous ray in midline depth; head length 31.2-32.5% of standard length; eye 32.8-35.7% of head length; caudal fin length 21.5-24.0% of standard length.