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Este artículo contiene 12 páginas, 5 tablas, 8 figuras., [EN]Decapod crustacean fisheries play a crucial role on the northwestern Mediterranean coast due to their high commercial value. Although knowledge of larval ecology and recruitment dynamics of these species is essential to establish a sustainable fisheries management, they are still poorly known. In this paper, we describe the composition, abundance and distribution of decapod crustacean larvae in the submarine canyon off Blanes (northwestern Mediterranean Sea) during summer thermal stratification conditions. Samples were collected in September 2011 with a multi-net system and a 60-cm bongo net at 22 stations with bottom depths of between 100 and 1800 m. A total of 635 larvae from 60 genera were identified. The most relevant taxa were Aristeus antennatus (7.93 individuals/1000 m3), the family Sergestidae (7.24) and Alpheus glaber (6.78). These three taxa were dominant (>20% of total decapod larvae) at more than half of the stations. Decapod larval communities were found to be richer and more diverse at the canyon head, a finding which could be explained by the higher retention rates when compared with the upstream and downstream walls and the canyon axis.[ES]Las pesquerías de crustáceos decápodos juegan un papel crucial en la costa del Mediterráneo noroccidental debido a su alto valor comercial. Aunque la información sobre la ecología larvaria y las dinámicas de reclutamiento de estas especies es esencial para establecer una gestión sostenible de estas pesquerías, estos aspectos son aún poco conocidos. En este estudio, se describe la composición, abundancia y distribución de las larvas de crustáceos decápodos en el cañón submarino de Blanes (Mediterráneo noroccidental) durante las condiciones de estratificación térmica estival. Las muestras fueron tomadas en septiembre de 2011 con un sistema multi-red y una red bongo de 60 cm de diámetro en 22 estaciones con fondos de entre 100 y 1800 m de profundidad. Un total de 635 larvas de 60 géneros fueron identificadas. Los taxones más relevantes fueron Aristeus antennatus (7.93 individuos/1000 m3), la familia Sergestidae (7.24) y Alpheus glaber (6.78). Estos tres taxones fueron dominantes (>20% del total de larvas de decápodos) en más de la mitad de las estaciones. Se encontró que las comunidades larvarias de decápodos son más ricas y diversas en la cabecera del cañón, lo cual podría explicarse por los altos índices de retención que presenta esta zona en comparación con las paredes del cañón y su eje., This research was carried out within project OAMMS (CTM2008-03983), financed by the Spanish Ministerio de Economía y Competitividad. Molecular analyses were done by AllGenetics (A Coruña, Spain)., With the funding support of the ‘Severo Ochoa Centre of Excellence’ accreditation (CEX2019-000928-S), of the Spanish Research Agency (AEI)

13 pages, 9 figures, 4 tables, 1 appendix, Crustacean suprabenthic abundance, community structure, α-diversity (both taxonomic and trophic) and β-diversity were studied along a West-East gradient of oligotrophy in the deep Mediterranean Sea. The assemblages were sampled with a suprabenthic sledge in three regions (western, central and eastern basins) at three water depths (1200, 2000 and 3000 m) in May-June 2009. Environmental data were obtained at each sampling location including sediment properties, oceanographic variables near the seafloor and in the water column, and proxies of epipelagic productivity at the surface. Our results, concerning the crustacean component of the suprabenthos, showed complex trends in community structure and biodiversity across different spatial scales (longitudinal, bathymetric, and near-bottom distribution). A decrease in the number of species and abundance, accompanied by changes in the trophic structure of the assemblages were observed from West to East. In the eastern region the assemblages were impoverished in number of trophic guilds and trophic diversity. The West-East oligotrophic gradient was identified as the main driver in community structure as shown by the significant correlation with trophic environmental variables. Differences in community structure across regions were more marked at greater depths, while at the shallower sites assemblages were more similar. Within each basin, abundance, number of species and number of trophic groups decreased with depth, showing high turnover rates between 1200 and 2000 m depths. The small-scale (0–150 cm) vertical distribution of the suprabenthos was interpreted in relation to the species’ functional traits (e.g. swimming activity, migratory behaviour, bottom dependence, feeding habits). Bottom-dependent and more mobile components of the suprabenthos were apparently responding differently to the various environmental challenges imposed by the large-scale longitudinal and bathymetric gradients. We propose that the bathyal suprabenthos in the Mediterranean Sea may be essentially modulated by environmental sorting, but while the more mobile faunal component has more efficient dispersal mechanisms, the bottom-dependent component may be affected by limited dispersal. However, this empirical interpretation has still to be proved given the important caveats of our study (e.g. typically low densities of the Mediterranean bathyal suprabenthos; limited number of samples; difficulties in standardization inherent to suprabenthic sampling operations in the deep sea), This work was funded through the BIOFUN project (CTM2007-28739-E) within the framework of the EuroCores EuroDEEP programme (European Science Foundation). This study was partially funded by Fundação para a Ciência e Tecnologia (FCT) under the projects PEst-C/MAR/LA0017/2013 and UID/AMB/50017/2013. The first author was funded by a PhD grant from FCT (SFRH/BD/69450/2010).

8 pages, 6 figures, 2 tables, This study describes the distribution and composition of litter from the Gulf of Cadiz (Northeastern Atlantic,Spain), a region of confluence between the Atlantic and Mediterranean, with intense maritime traffic. Several geological features, such as canyons, open slopes and contourite furrows and channels, were surveyed by remotely operated vehicle (ROV) observations between depths of 220 and 1000 m. Marine litter was quantified by grouping the observations into six categories. Our results indicate the presence of markedly different habitats in which a complex collection of different types of litter accumulate in relation to bottom current flows and maritime and fishing routes. This result justifies a seascape approach in further anthropogenic impact studies within deep-sea areas, The present study was developed in the framework of the Tecnoterra (ICM-CSIC/UPC) Associate Unit and the following project activities, funded by the Spanish Government MOWER (CTM2012-39599-C03), FAUCES (CTM2015-65461-C2-1-R) and RESBIO (TEC2017-87861-R), plus the ARIM (Autonomous Robotic sea-floor Infrastructure for benthopelagic Monitoring) funded by the MartTERA ERA-Net Cofound. Francescangeli M. was funded by the European Project ERASMUS grant 2017. Mecho A. was partially funded by the Pure Ocean Fund, managed by the King Baudouin Foundation, With the funding support of the ‘Severo Ochoa Centre of Excellence’ accreditation (CEX2019-000928-S), of the Spanish Research Agency (AEI)

Special issue Bridging the gap between the shallow and deep oceans: The key role of submarine canyons.-- 13 pages, 8 figures, 4 tables, supplementary material https://doi.org/10.1016/j.pocean.2018.02.022, Submarine canyons and adjacent slopes from the NW Mediterranean Sea are subjected to high seasonal and inter-annual variability in hydrodynamic processes. Such an environmental setting has a profound influence in the spatial and temporal variability of deep-sea benthic assemblages. We analyzed the suprabenthic crustacean assemblages from the Blanes Canyon and the adjacent slope along a bathymetric gradient. Macer-Giroq sledge hauls were taken from 900 to 2250 m depth in the canyon axis and southwestern adjacent slope in the autumn of 2008, 2009 and 2012. From the twenty four hauls sampled, one hundred and seventy one species were identified. Major changes in densities, number of species and diversity were only found at particular depths or years. In general the samples yielded variable densities (from approx. 10 to 539 ind.100 m), mostly owing to temporal fluctuations in motile fauna such as amphipods and mysids, in relation to the occurrence of energy-driven events. The environmental conditions associated to these events coupled with particular topographic features at the shallowest sites (namely at 900 m depth) lead to contrasting biodiversity patterns in the canyon and adjacent slope: high dominance and subsequent depressed diversity in the canyon and the highest diversity on the slope at similar depths. At the deepest sites, suprabenthic diversity reached similar values in the canyon and adjacent slope, probably owing to the decreased influence of disturbance processes at greater depths. Trophic diversity decreased with depth only in the slope, while in the canyon it remained constant likely owing to the relatively enhanced trophic conditions found in the canyon at all depths. However, the community composition differed significantly between the canyon and adjacent slope and at contrasting depths (1200 m). At shallowest depths, the canyon sites were characterized by a high contribution of motile omnivores while the slope sites were characterized by a high contribution of detritivores to the total abundance. Highly motile predators on zooplankton were dominant at deepest sites in both environments. Our results suggest that taxonomic and trophic diversity in the northwestern Mediterranean may be influenced by the abrupt topography and its interaction with hydrodynamic conditions (intensification of currents; variable intensity of disturbance/hydrodynamic events; food pulses linked to food availability). These are major drivers which influence the spatial and temporal availability of food sources to the various faunal compartments eventually propagating up the food web, The present work was funded by the MICYT Project PROMETEO (CTM2007-66316-C02/MAR), the European Science Foundation Project BIOFUN (CTM2007-28739-E) and Project DOS MARES (CTM2010-21810-C03-03). This work was supported by CESAM (UID/AMB/50017) funds, granted by FCT/MEC through national funds, and the co-funded by FEDER, within the PT2020 Partnership Agreement and Compete 2020. The first author was funded by a PhD grant from FCT (SFRH/BD/69450/2010).

11 pages, 10 figures, 4 tables, The deep-sea red shrimp Aristeus antennatus is one of the most valuable demersal resources for bottom trawl fishery in the Mediterranean Sea. Nevertheless, this fishery lacks specific management at Mediterranean level, data availability is sparse and official records are often unreliable. In particular, misreporting of trawlers engine power is a widespread issue, complicating the process of fish stock assessments. In Catalonia (Northeast Spain), the red shrimp is particularly important and the stock has been traditionally exploited. The aim of this study was to investigate the long-term effects of intense fishing activities on this resource. For this purpose, we built a reliable series of fishing effort and catch per unit of effort (CPUE), integrating official data with information obtained by interviews to fishermen. Stock assessment at two different time periods, 1984-1989 and 2008-2010, was performed. In this study, we provide the first evidence of the remarkable increase of fishing effort in the Northwest Mediterranean Sea in the last decades. Overfishing of the red shrimp was detected at all years studied. A decrease in the yield per recruit and mean individual length over the two time periods considered was also detected. In addition, the CPUE presented a marked decreasing trend, indicating a possible reduction in the resource abundance. Our results show that an appropriate fishery management for this resource is needed, and should aim at reducing fishing mortality and increasing yield per recruit. These objectives could be achieved by reducing fishing effort and increasing size at first capture, The EC Program Science in Society EC. FP7 (ref # 266544-GAP2), the Generalitat de Catalunya Monitoring Project no.070105070011, the FPU grant of the Spanish Ministry of Education and the Marine Stewardship are acknowledged for financial support

Este artículo contiene 12 páginas , 7 figuras, 3 tablas, This study reports the composition and distribution of demersal megafauna from various north-western Mediterranean submarine areas such as canyons, seamounts and landslides between 60–800 m depth, based on remotely operated vehicle (ROV) observations. From a total of 30 h of video, 4534 faunistic observations were made and analysed in relationship to environmental factors (i.e. topography, substrate type and depth). In addition, anthropogenic impact was quantified by grouping observations in four categories: fishing nets, longlines, trawl marks and other litter. The different targeted environments showed similarities in faunal composition according to substrate, depth and topography. Our results also indicated the presence of anthropogenic impact in all the sampled areas in which litter and trawl marks were the most observed artefacts.

Special Issue Integrated study of a deep submarine canyon and adjacent open slopes in the Western Mediterranean Sea: an essential habitat.-- 11 pages, 7 figures, 2 tables, Throughout the deep oceans, diversity in the benthos peaks at intermediate slope depths. In the western Mediterranean lower slope an accumulation of biomass, but not diversity, at depths of 1200-1350. m has been observed. However, the precise causes of this biomass peak are unknown. We examined the patterns of megafauna benthic biomass in the Catalan sea open slope, from 900 to 1750. m depth, expanding the results in the context of the whole continental margin. Sampling was carried out by combining an Otter-Trawl Maireta System (OTMS) and an Agassiz trawl, during four different seasons in 2008/2009. At the same time, current speed, temperature and salinity were obtained year-round by means of near-bottom deployed sensors (current meters and temperature-conductivity sensors). Total biomass followed an inverted U-shaped pattern, peaking at depths of 1050-1350. m. Range-related ecological forcings between shallower and deeper species may have caused this biomass accumulation at intermediate slope depths. We also report on the seasonal variations of biomass in the studied depth range, identifying a dynamic zone above 1000. m depth where populations of highly mobile species perform year-round migrations throughout the slope, and a more static region below 1000. m (i.e. the twilight zone end) with substantially less inter-annual variations. The arrival of new Western Mediterranean Deep Water from the deep basin to the lower slope in March-May may have driven the accumulation of biomass at 900 and 1050. m depth over the same period. In addition, an adjacent submarine canyon was sampled with the same procedures to characterize its benthic megafauna community. Analyses revealed higher diversity, but not biomass, inside the canyon than in the adjacent open slope, and a significantly different assemblage composition between the two habitats. These results strengthen the concept of submarine canyons as hotspots of biodiversity and underline the importance of their conservation as diversity repositories. © 2013 Elsevier Ltd., The present work was funded by the MICYT Project PROMETEO (CTM2007-66316-C02/MAR), the European Science Foundation Project BIOFUN (CTM2007-28739-E) and the European Community HERMIONE Project (FP7/2007–2013, Grant agreement no. 226354). Physical analyses were also supported by the GRACCIE-CONSOLIDER (CSD2007-00067) research project, and a Generalitat de Catalunya ‘Grups de Recerca Consolidats’ grant (2009 SGR 1305). S.T. was funded by a JAE-PRE-2008 grant and ERLL by a JAE-DOC grant, both from the CSIC and co-financed by the European Union. J.A. and A.S. are postdoctoral fellows of the Ramón y Cajal program (MICINN)

Special issue Integrated study of a deep submarine canyon and adjacent open slopes in the Western Mediterranean Sea: an essential habitat.-- 15 pages, 10 figures, 2 tables, The distribution, type and quantity of marine litter accumulated on the bathyal and abyssal Mediterranean seafloor has been studied in the framework of the Spanish national projects PROMETEO and DOS MARES and the ESF-EuroDEEP project BIOFUN. Litter was collected with an otter trawl and Agassiz trawl while sampling for megafauna on the Blanes canyon and adjacent slope (Catalan margin, north-western Mediterranean) between 900 and 2700 m depth, and on the western, central and eastern Mediterranean basins at 1200, 2000 and 3000 m depth. All litter was sorted into 8 categories (hard plastic, soft plastic, glass, metal, clinker, fabric, longlines and fishing nets) and weighed. The distribution of litter was analysed in relation to depth, geographic area and natural (bathymetry, currents and rivers) and anthropogenic (population density and shipping routes) processes. The most abundant litter types were plastic, glass, metal and clinker. Lost or discarded fishing gear was also commonly found. On the Catalan margin, although the data indicated an accumulation of litter with increasing depth, mean weight was not significantly different between depths or between the open slope and the canyon. We propose that litter accumulated in the canyon, with high proportions of plastics, has predominantly a coastal origin, while litter collected on the open slope, dominated by heavy litter, is mostly ship-originated, especially at sites under major shipping routes. Along the trans-Mediterranean transect, although a higher amount of litter seemed to be found on the Western Mediterranean, differences of mean weight were not significant between the 3 geographic areas and the 3 depths. Here, the shallower sites, also closer to the coast, had a higher proportion of plastics than the deeper sites, which had a higher proportion of heavy litter and were often affected by shipping routes. The weight of litter was also compared to biomass of megafauna from the same samples. On the Blanes slope, the biomass of megafauna was significantly higher than the weight of litter between 900 and 2000 m depth and no significant differences were found at 2250 and 2700 m depth. Along the trans-Mediterranean transect, no significant differences were found between biomass and litter weight at all sites except in two sites: the Central Mediterranean at 1200 m depth, where biomass was higher than litter weight, and the Eastern Mediterranean at 1200 m depth, where litter weight was higher than biomass. The results are discussed in the framework of knowledge on marine litter accumulation, its potential impact on the habitat and fauna and the legislation addressing these issues, This study was funded by the PROMETEO project (CTM2007-66316-C02/MAR, CICYT), the BIOFUN project (CTM2007-28739-E, European Science Foundation and national funding agencies), the DOS MARES project (CTM2010-21810-C03-03) and the European Community’s Seventh Framework Programme under the HERMIONE project (Grant Agreement 226354). EZR is funded by a JAE-DOC CSIC postdoctoral grant with co-funding from the European Social Fund. MC was funded by EC Marie-Curie IOF Fellowship to ECOFUN and Spanish Fellowship Program Ramón y Cajal

Special issue Integrated study of a deep submarine canyon and adjacent open slopes in the Western Mediterranean Sea: an essential habitat.-- 11 pages, 4 figures, 3 tables, Due to their geomorphological structure and proximity to the coastline, submarine canyons may act as natural conduit routes for anthropogenic contaminants that are transported from surface waters to the deep-sea. Organisms dwelling in these canyon environments might thus be at risk of experiencing adverse health effects due to higher pollution exposure. To address this question, chemical and biochemical analyses were conducted on two of the most abundant deep-sea fish species in the study area, namely Alepocephalus rostratus and Lepidion lepidion, and the most abundant deep-sea commercial decapod crustacean Aristeus antennatus sampled inside Blanes canyon (BC) and on the adjacent open slope (OS). Persistent organic pollutants (POPs) levels, including polychlorinated biphenyl (PCB), dichlorodiphenyltrichloroethane (DDT) and derivatives, hexachlorocyclohexanes (HCHs) and hexachlorobenzene (HCB) were determined in muscle tissue of selected samples from 900. m and 1500. m depth. Potential effects resulting from contaminant exposure were determined using hepatic biomarkers such as ethoxyresorufin. -O-deethylase (EROD), pentoxyresorufin. -O-deethylase (PROD), catalase (CAT), carboxylesterase (CbE), glutathione-. S-transferase (GST), total glutathione peroxidase (GPX), glutathione reductase (GR) and superoxide-dismutase (SOD) enzyme activities and lipid peroxidation levels (LP). L. lepidion and A. antennatus tissues exhibited higher POP levels inside BC compared to the OS at 900. m depth. These findings were consistent with biomarker data (i.e. enzymatic response to presence of contaminant agents). Elevated xenobiotic-metabolizing (EROD and PROD) and antioxidant enzymes (CAT and GPX) indicated higher contaminant exposure in both species caught within BC. No difference in POP accumulation between sites was observed in L. lepidion at 1500. m depth, nor in biomarker data, suggesting that the pollution gradient was less pronounced at greater depths. This trend was further corroborated by the results obtained for A. rostratus at 1500. m depth. Hence, the present findings suggest the, at least temporary, existence of a pollution gradient between Blanes canyon and the open slope at shallower depths and this resulted in alterations of the physiology of deep-sea organisms dwelling within this area. © 2013 Elsevier Ltd., The present work was funded by the Spanish Science and Technology Ministry Projects PROMETEO (CTM2007-66316-C02-02/MAR to JBC), DOS MARES (CTM2010-21810-C03-03/MAR to JBC), BIOFUN (CTM2007-28739-E/MAR to Francesc Sardà) and HERMIONE Project (EC-FP7 Contract Number 226354). Samuel Koenig holds a PhD Grant (AFR 08/067) from the Fonds National de la Recherche (FNR), Luxembourg

17 páginas, 8 figuras, 5 tablas, 1 apéndice con 3 tablas., Blanes Canyon and its adjacent margin are important fishery areas (mainly by bottom trawling) located in a highly energetic oceanographic setting in the NW Mediterranean Sea. Here we assess the spatial and temporal variability in abundance, diversity and community structure of the suprabenthic peracarid assemblages in this region and examine this variability in relation to the natural and anthropogenic (trawling fisheries) disturbance regimes. The sampling was conducted between March 2003 and May 2004 in three main fishing grounds, the canyon head (average depth: 490 m), the canyon wall (average depth: 550 m) and the eastern adjacent slope (average depth: 820 m), as well as in two non-exploited areas in the western (at 900 m depth) and eastern (at 1500 m depth) slope near the canyon mouth. A total of 138 species were identified, with amphipods being the most speciose and abundant group, followed by mysids in terms of abundance. Our results show high spatial and temporal variability in suprabenthic assemblages. Densities were higher in the canyon head and western slope, which appear to be the preferential routes for water masses and particle fluxes in months of flood events, and other energetic processes. In the canyon head, where periodic erosion processes are more active, low diversity, high dominance and higher turnover (β-diversity) were observed, apparently coupled with significant temporal fluctuations in the densities of the highly motile component of suprabenthos (mysids, predatory and scavenging amphipods). In the sedimentary more stable eastern slope, high diversity values were observed, accompanied by a higher relative contribution of the less motile groups (i.e. amphipods, most isopods, cumaceans). These groups have a closer interaction with the sediment where they exploit different food sources and are more susceptible to physical disturbance. Temporal variability in their diversity may be related to changes in food quality rather than quantity. In the canyon wall, temporal fluctuations in diversity indices were only revealed in relation to the overall higher and more continued fishing pressure observed in the canyon wall fishing ground (Cara Norte/Sot site). Here, species richness and abundance declined with increasing fishing pressure but the lowest trophic and taxonomic diversities were observed under intermediate levels of disturbance. These findings underline (i) the differences between relatively low and highly motile taxa in terms of response to disturbance events; (ii) the differences between assemblages subjected to different levels of natural disturbance and trawling pressure, which modify the common bathymetric patterns of abundance and diversity often described from continental margins., This study was conducted within the framework of the project RECSII (REN02/04556/C02/ MAR) by the Spanish Science and Innovation Agency. The study is a contribution of D. Martin to the Consolidated Research Group 2014SGR120 of the Generalitat de Catalunya. The first author was supported by Fundação para a Ciência e Tecnologia: SFRH/BPD/ 21459/2005. C. Romano received funding from the People Programme (Marie Curie Action) of the European Union's Seventh Framework Programme (FP7/2007-2013) under REA grant agreement N. PIOF-GA-2013-628146. This study was partially funded by Fundação para a Ciência e Tecnologia (FCT) under the projects PEst-C/MAR/LA0017/2013 and UID/AMB/50017/2013.

12 páginas, 6 figuras, 5 tablas., There is a general hypothesis that species inhabiting deep-sea waters have lower fecundity and larger eggs than shallower species. However, there are few comparative studies which explore this trend because of the complexity of sampling in deep waters, especially in fishes. We present here the first analysis of fecundity and egg size with depth along an isothermal environment. We calculate the relative fecundity and egg size of 11 species of demersal deep-sea fish from the western Mediterranean and included in our analyses published data for an additional 14 species from the same geographic area. The results show that the relative fecundity (eggs per g of individual) of the analyzed fishes slightly decreased along the bathymetric gradient, whereas egg size increased with depth. When the analysis was conducted including only species from the order Gadiformes, the most speciose group in the region and with the widest depth range of distribution (50–2000 m), there was no relationship between relative fecundity and depth, while the deepest species had larger egg sizes than shallower ones. The finding of similar relative fecundities but larger egg sizes suggests that these deep-sea species are investing a higher amount of energy in the production of offspring than shallower water counterparts. The results are discussed in relation to the isothermal characteristics of the deep Mediterranean Sea and ecological adaptations for reproductive success., This study was conducted within the framework oft he RECS(REN02/04556/C02/MAR), PROMETEO(CTM2007-66316-C02/MAR) and DOSMARES (CTM2010-21810-C03-03/MAR) projects by the Spanish Science and Innovation Ministry respectively, to JBC.

5 pages, 4 figures, Bottom trawling is a non-selective commercial fishing technique whereby heavy nets and gear are pulled along the sea floor. The direct impact of this technique on fish populations1, 2 and benthic communities3, 4 has received much attention, but trawling can also modify the physical properties of seafloor sediments, water–sediment chemical exchanges and sediment fluxes5, 6. Most of the studies addressing the physical disturbances of trawl gear on the seabed have been undertaken in coastal and shelf environments7, 8, however, where the capacity of trawling to modify the seafloor morphology coexists with high-energy natural processes driving sediment erosion, transport and deposition9. Here we show that on upper continental slopes, the reworking of the deep sea floor by trawling gradually modifies the shape of the submarine landscape over large spatial scales. We found that trawling-induced sediment displacement and removal from fishing grounds causes the morphology of the deep sea floor to become smoother over time, reducing its original complexity as shown by high-resolution seafloor relief maps. Our results suggest that in recent decades, following the industrialization of fishing fleets, bottom trawling has become an important driver of deep seascape evolution. Given the global dimension of this type of fishery, we anticipate that the morphology of the upper continental slope in many parts of the world’s oceans could be altered by intensive bottom trawling, producing comparable effects on the deep sea floor to those generated by agricultural ploughing on land, This work was supported by various research projects: HERMIONE (226354 and CTM2010-11084-E), DOS MARES (CTM2010-21810-C03),OASIS DEL MAR—Obra Social ‘‘la Caixa’’, GRACCIE-CONSOLIDER (CSD2007-00067) and REDECO (CTM2008-04973-E). We also received support from Catalan Government Grups de Recerca Consolidats grants (2009 SGR 899 and 1305). VMS data and support were provided by the Spanish General Secretariat of Maritime Fishing (SEGEMAR). Assistance at sea by the crews of RV Hespérides, RV Sarmiento de Gamboa and RV García del Cid is also acknowledged. J.M. was funded through a JAE-DOC contract granted by Consejo Superior de Investigaciones Científicas and co-financed by the European Social Fund. F. Sarda and T. Milligan provided comments on the manuscript. The final document benefited from a review by P. Talling

12 pages, 10 figures, 6 tables, Macrourid fish are one of the most abundant marine species on continental margins worldwide. Although they play an important role in the ecosystem, little is known about their overall biology. We report here a large data set of the most abundant macrourid in Mediterranean waters, Trachyrincus scabrus, showing the main population and reproductive characteristics. The study was based on 3,239 specimens collected between 300 and 1,500 m depth on the northwestern Mediterranean in 2003–2004 and 2008–2009. The population showed a depth-related structure with the largest individuals at 1,100 m depth and the smallest (i.e., immature) at shallower depths. Macroscopic and microscopic analyses of the gonads showed that T. scabrus has a highly seasonal reproductive pattern. Spawning females were found during winter when the organic matter fluxes were highest on the continental slope. T. scabrus is a batch spawner with group-synchronous oocyte development and present low average fecundity of 14,191 oocytes, The authors would like to thank the Officers and crews of the R/V Garcia del Cid, F/V Montse III and Virgen del Vilar for helping to provide samples and the data necessary for our study. We also thank I Quagio-Grassiotto, M Metaksakis and C Cerviño for helping with the histological analyses and JA Garcia for developing the study area map. This study was conducted within the RECS, PROMETEO and DOS MARES projects by the Spanish Science and Innovation Ministry CICYT (REN02/04556/C02/MAR; CTM2007-66316-C02/MAR; CTM2010-21810-C03-03/MAR, respectively, to JBC) and European Community’s Seventh Framework Programme under the HERMIONE project (Grant Agreement 226354, to ERLL). UF-A is funded by a Spanish PhD doctoral fellowship FPI-2008. ERLL is funded by a Spanish JAE-CSIC postdoctoral grant. This paper is a contribution number 580 from AZTI Tecnalia (Marine Research Division)

Aguzzi, Jacopo ... et. al.-- 21 pages, 7 figures, 1 table, The inclusion of behavioral components in the analysis of a community can be of paramount importance in marine ecology. Diel (i.e., 24-h based), seasonal activity rhythms, or longer durational in behavioral responses can result in shifts in populations, and therefore on measurable abundances. Here, we review the value of developing cabled video observatory technology for the remote, long-term, and high-frequency monitoring of fish and their environments in coastal temperate areas. We provide details on the methodological requirements and constraints for the appropriate measurement of fish behavior over various seasonal scales (24 h, seasonal, annual) with camera systems mounted at fixed observatory locations. We highlight the importance of using marine sensors to simultaneously collect relevant environmental data in parallel to image data acquisition. Here we present multiparametric video, oceanographic, and meteorological data collected from the Mediterranean observatory platform, OBSEA (www.obsea.es; 20 m water depth). These data are reviewed in relation to ongoing and future developments of cabled observatory science. Two key approaches for the future improvement of cabled observatory technology are: (1) the application of Artificial Intelligence to aid in the analysis of increasingly large, complex, and highly interrelated biological and environmental data sets, and (2) the development of geographical observational networks to enable the reliable spatial analysis of observed populations over extended distances. © 2015, Springer International Publishing Switzerland, This research was funded by RITFIM (CTM2010-16274) and European Multidisciplinary Seafloor Observation (EMSO Preparatory Phase-FP7 Infrastructures-2007-1, Proposal 211816). Researchers from CSIC-UPC are members of the Associated Unit Tecnoterra. The paper was also partially funded by the Helmholtz Alliance ‘‘Robotic Exploration of Extreme Environments (ROBEX)’’ project. I.A. Catalán was partially supported by REC2 from the Spanish Government, CTM2011-23835

[EN] Three deep-sea areas in the Mediterranean Sea were sampled using a bottom otter trawl during the DESEAS oceanographic survey carried out from early June to early July 2001, covering an area in the western Mediterranean from 600 to 2800 m in depth and two areas in the central Mediterranean, the western and eastern Ionian Sea from 600 to 4000 m in depth. Decapod crustaceans were one of the dominant megafaunal groups, together with fishes, in terms of both biomass and abundance. A total of 2799 decapod specimens belonging to 32 species were collected. Abundance and biomass of the decapod crustaceans decreased with depth. For depths below 1000 m, a decrease in total decapod biomass was recorded from west to east. From the data reported in this study and data from the available literature, decapod crustaceans display differential depth distributions in the different areas. For the most abundant species, size and sex distributions versus depth gradient were examined to compare intraspecific population structures between the sampling areas. Despite differences, among areas, in the species biomass compositions by depth strata and differences in their overall bathymetric ranges of distribution, intraspecific population structures of the most abundant species seem to follow similar trends for size and sex distribution versus depth gradient between the western and central areas. This might be an indication that the individual species structure their populations according to a similar basic pattern regardless of differences in local environmental features. The results have been discussed in the general context of the environmental features encountered by the species in each of the sampling areas, [ES] Se muestrearon tres áreas del mediterráneo profundo con una red de arrastre bentónica durante la campaña oceanográfica DESEAS, desde principios de junio hasta principios de julio de 2001. El rango batimétrico muestreado en el Mediterráneo occidental fue entre los 600 y los 2800 m de profundidad. El rango batimétrico muestreado en el Mediterráneo occidental fue entre los 600 y los 2800 m de profundidad. Se muestrearon dos áreas del Mediterráneo central, una situada en la parte occidental del Mar Iónico y la otra situada en la parte más oriental del mismo, cubriendo un rango batimétrico entre los 600 y 4000 m de pro- fundidad. Los crustáceos decápodos fueron uno de los grupos, junto con los peces, dominantes de la megafauna en términos de biomasa y abundancia. Se capturaron un total de 2799 individuos de decápodos pertenecientes a 32 especies. La abundancia y biomasa de los crustáceos decápodos disminuyó con la profundidad. Teniendo en cuenta únicamente las muestras tomadas a profundidades superiores a los 1000 m, se detectó una disminución de la biomasa total de los crustáceos decápodos en el área de muestreo más oriental (parte oriental del Mar Iónico) con respecto al Mediterráneo occidental (Mar Balear). Los datos aportados en este estudio junto con los datos disponibles en la literatura, indican que los crustáceos decápodos se distribuyen en rangos batimétricos diferentes en cada una de las áreas de estudio. Aunque se encontraron diferencias entre las áreas de estudio, en la distribución de biomasa con respecto a la profundidad y en los rangos batimétricos de cada especie, la estructura de población de las especies más abundantes parece seguir la misma tendencia por lo respecta la distribución batimétrica de sexos y tamaño de sus individuos en toda el área geográfica muestreada. Este último aspecto podría ser una indicación de que las especies estructuran sus poblaciones de acuerdo a un patrón similar, independientemente de las diferencias locales del ambiente. Los resultados se han discutido bajo el contexto general de las características ambientales encontradas por cada especie en cada una de las áreas de muestreo

The deep-sea red shrimp Aristeus antennatus is one of the most valuable demersal resources in Catalonia (northeast Spain), and Palamós is the most important harbour for this fishery in the area. Here, a management plan published in 2013 established the use of a 40-mm square-mesh codend (40s), replacing the previously used 50-mm diamond mesh codend (50d). The objective was to decrease the amount of juveniles in the catches, but the regulation did not bring the expected results. In this study, we measured and compared the selectivity of the 40s and the 50d in this fishery. In addition, we experimented with the use of a 50-mm square-mesh codend (50s). According to our results, the 40s had a lower 50% selection length (L50) than the 50d, while the 50s had a substantially higher L50 than the other two. A transition analysis showed an increase in yield per recruit after the second year from a hypothetical implementation of the 50s. Our conclusion is that the 40s does not have a higher selectivity than the 50d, which (at least partially) explains the failure to reach the management objective in Palamós. Conversely, the use of a 50s would significantly benefit the fishery, increasing gear selectivity and yield per recruit.

22 pages, 13 figures, 3 tables, [EN] This study provides a compilation of all available information on deep-sea echinoderms from the middle and lower slopes of the Mediterranean Sea, with the aim of providing a unified source of information on the taxonomy of this group. Previous records of species are updated with new data obtained from 223 trawl hauls conducted in 11 cruises within the northwestern Mediterranean Sea between 800 m and 2845 m depth. Valid names, bathymetric ranges and geographic distributions are given for all species. The new data report, for the first time, the presence of the Atlantic echinoid Gracilechinus elegans (Düben and Koren, 1844) in the Mediterranean Sea. We also report the presence of the endemic holothurians Hedingia mediterranea (Bartolini Baldelli, 1914), dredged only once previously in 1914 in the Tyrrhenian Sea, and Penilpidia ludwigi (von Marenzeller, 1893), known previously only from three samples, two in the Aegean Sea and one in the Balearic Sea. Additionally, the deeper limits of the bathymetric distribution of four species have been expanded: the asteroid Ceramaster grenadensis (Perrier, 1881) to 2845 m; the echinoid Brissopsis lyrifera (Forbes, 1841) to 2250 m; and the holothurians Hedingia mediterranea and Holothuria (Panningothuria) forskali Delle Chiaje, 1823, to 1500 m and 850 m, respectively, [ES] Este estudio presenta una recopilación de toda la información disponible sobre los equinodermos de profundidad en el talud continental medio e inferior del mar Mediterráneo, con el fin de proporcionar una fuente de información unificada sobre la taxonomía de este grupo. Se han actualizado los registros anteriores mediante nuevos datos provenientes de 223 pescas de arrastre de 11 campañas oceanográficas realizadas en el noroeste Mediterráneo entre 800 y 2845 m de profundidad. Se ha actualizado el nombre de las especies, sus rangos batimétricos y sus distribuciones geográficas. Los nuevos datos presentan, por primera vez, la presencia del equinoideo Atlántico Gracilechinus elegans (Düben and Koren, 1844) en el mar Mediterráneo. También se cita la presencia en el noroeste Mediterráneo de dos especies de holoturias endémicas del Mediterráneo, Hedingia mediterranea (Bartolini Baldelli, 1914), muestreada una única vez en 1914 en el mar Tirreno, y Penilpidia ludwigi (von Marenzeller, 1893), muestreada tres veces, dos en el mar Egeo y una en el mar Balear. Además se expanden los límites de distribución batimétrica para cuatro especies: el asteroideo Ceramaster grenadensis (Perrier, 1881) hasta 2845 m; el equinoideo Brissopsis lyrifera (Forbes, 1841) hasta los 2250 m; y las holoturias Hedingia mediterranea y Holothuria (Panningothuria) forskali Delle Chiaje, 1823, hasta los 1500 m y 850 m respectivamente, This study was funded by the PROMETEO project (CTM2007-66316-C02/MAR, CICYT), the BIOFUN project (CTM2007-28739-E, European Science Foundation and national funding agencies) and the DOSMARES project (CTM2010-21810-C03-03). ERLL was funded by a JAE-DOC postdoctoral grant (CSIC, Spain) with co-funding from the European Social Fund. JA is a fellow of the Ramón y Cajal Programme (MICINN)

13 pages, 3 figures, A clear link between the distribution of intermediate nepheloid layer detachments on the Northwestern Mediterranean continental margin and the population structure of five congeneric megafaunal species of deep-water benthic shrimps inhabiting different depth ranges between 100 and 1100m was found. The results of the multidisciplinary approach presented in this study provide evidence for the ecological conditions that affect the spatial distribution of juveniles and females of a deep-water fishery resource. The significantly higher occurrence of juveniles and females in regions where intermediate nepheloid layers detach from the seabed allows us to define these areas as potential deep-water nursery habitats. The spatial recognition of these habitats could contribute to the management of the stocks concerned and afford a basis for protecting these vulnerable habitats from fishing pressure. Overall, our findings furnish support for the hypothesis that deep-water benthic biological processes are linked to pelagic processes, suggesting that the detachments of intermediate nepheloid layers serve as one of the physical links between these two environments. © 2001 Elsevier Science Ltd, This work was supported by the European Commission (projects MED 92/008 to F. Sardà and MAS2-CT93-0053 and MAS3-CT95-0037 to A. Palanques) and by the Spanish Interdepartmental Commission for Science and Technology (CICYT) (projects MAR90-0757 to F. Sardà and MAR96-1781-CO-01 to A. Palanques). P. Puig and J.B. Company were supported by grants from the Generalitat of Catalonia and from the Spanish Ministry of Education and Culture, respectively

Relative and absolute growth were studied in 17 species of deep-water decapod crustaceans, spanning nine families of six different infra-orders, in the Northwestern Mediterranean Sea. The overall maximum abundance of these species lay between 200 m and 750 m (i.e. upper- and mid-slope species). Relative and absolute growth rates were compared by contrasting the slopes of the size–weight relationships for the different species and calculating the von Bertalanffy growth-equation parameters asymptotic length (L ∞ ) and growth rate (k). The size–weight relationships differed significantly as function of the species' life habits. The results revealed a significant decrease in weight relative to size in mesopelagic species (which carry out diel vertical migrations), an almost isometric relationship between size and weight in the less mobile nektobenthic species, and a significant increase in weight relative to size in strictly benthic species. The mean allometric coefficient for each group increased significantly from mesopelagic to benthic species. However, no general trend was observed in the growth-performance index, Φ (an index used to compare absolute growth rates between species, as a function of habit and depth of maximum abundance for all species combined), suggesting that the deep-water decapod crustaceans studied have similar absolute growth rates. Nevertheless, comparison of growth-parameter and growth-performance index values within families did reveal differences. Mesopelagic species of the families Sergestoidae and Pasiphaeidae showed slightly increased growth rates with increasing depth of distribution. Nektobenthic species of the genus Plesionika followed a trend opposite to that shown by mesopelagic species, with a higher growth rate for the shallowest-dwelling species (P. heterocarpus) than the deepest-dwelling species (P. acanthonotus). Taking growth as one of the major components of an organism's energy budget, the growth rates for the decapod crustacean species in this study were significantly lower than those reported in the literature for shallow-water penaeid crustacean species (which are distributed in higher-temperature habitats than deep-water Mediterranean crustaceans) and higher than those reported for mesopelagic myctophid fish species. Hence, the well-defined growth trends shown by deep-water decapod crustacean species in the Northwestern Mediterranean Sea, compared to the less well-defined trends in the other taxa, is discussed in the framework of the overall dynamics of their ecosystem.

Special issue Integrated study of a deep submarine canyon and adjacent open slopes in the Western Mediterranean Sea: an essential habitat.-- 13 pages, 7 figures, 2 tables, To characterize the temporal and spatial variability of total mass fluxes in the Blanes submarine canyon and the nearby southern open slope, eight near-bottom sediment traps were deployed at 300, 900, 1200 and 1500m along the canyon axis, and at 900, 1200, 1500 and 1800m of water depth on the southern open slope from November 2008 to November 2009. The results obtained show that mass fluxes were higher into the canyon, ranging from 0.05 to 82.67gm-2d-1, compared with those from the open slope that ranged from 0.01 to 9.91gm2d-1. Both environments were highly influenced by atmospheric forcing and showed increased total mass fluxes during autumn and winter months. The spatial distribution of total mass fluxes and major constituents (organic matter, carbonate, opal and lithogenics) highlights the contrasts amongst the two physiographic domains in the study area (canyons vs. open slope). The temporal evolution of particle fluxes shows three distinct situations succeeding each other along the year. These are determined by: (1) storms in autumn and winter, driving 60% of the annual total mass flux in Blanes Canyon and 44% in the open slope stations, and also 60% and 40% of the annual OC flux in Blanes Canyon and the southern open slope, respectively; (2) open sea convection in late winter and spring, which is accompanied by a phytoplankton bloom and drives 13% of the settling OC in the canyon and 34% in the open slope; and (3) dust inputs and resuspension by bottom trawling in late spring and -summer months, driving 17% of the annual OC flux in the canyon and 18% in the slope. © 2013 Elsevier Ltd., This research has been supported by Spanish and EU funded projects PROMETEO (CTM2007-66316-C02-01/MAR), DOS MARES (CTM2010-21810-C03-01), GRACCIE-CONSOLIDER (CSD2007-00067), PERSEUS (GA 287600) and REDECO (CTM2008-04973-E/MAR) RTD projects. University of Barcelona researchers are supported by grant 2009 SGR 1305 of Generalitat de Catalunya. P.L.F. benefited from a Spanish FPI Grant (BES-2008-009374)

2013 IEEE International Underwater Technology Symposium (UT), 5-8 March 2013, Tokyo, Japan.-- 8 pages, 6 figures, Constraints in sampling repeatability at statistically relevant frequencies are limiting the progress of marine ecology, especially in the vast and still largely unexplored deep sea. Within the framework of novel cabled observatory science, it is now possible to study and monitor the fauna of geologically different ecosystems at any depth of the continental margin and abyssal plains, at sampling frequencies and over temporal durations never attained before (i.e. from seconds to decades). New multiparametric platforms endowed with video cameras that are being progressively installed in different oceans, can be used not only for a broad faunal characterization but also to quantify the massive three-dimensional displacements of marine populations in response to cyclic oceanographic, chemical, and geologic fluctuations (also measured in a multiparametric fashion). Here, we will review how automated video-imaging protocols for animal classification and counting could be implemented to transform the video-camera into one of the first intelligent marine sensors for remote, autonomous and continuous monitoring of communities in relation to their diel (i.e. inertial, internal-tidal or day-night), seasonal, and inter-annual cycles of functioning. We will also discuss the possibility to study the responses of benthic species to other more stochastic habitat changes (e.g. those induced in the water column by the meteorology), through the measurement of modifications in water column properties by observatory vertical elongations. Studies of this kind may allow an efficient modeling of marine community modifications in view of future climate change scenarios, based on alterations of the benthopelagic coupling equilibrium. A special emphasis will also be given to the faunal monitoring prior and after catastrophic events (e.g. seismic activity or tsunamis), to initiate a critical discussion on the reliability of biologically-based early warning systems based on the continuous moni- oring of the deep sea. The reliability of these systems should be evaluated by considering whether significant changes in automatically video-counted benthos occur prior to, or only after, the incoming catastrophe, The present work was developed within the framework of different research projects funded by: 1) the Spanish Ministry for Science and Innovation as PROMETEO (ref. CTM 2007-66316-C02-02), RITFIM (ref. CTM2010-16274), Operatividad Laboratorio Submarino OBSEA (ref. ACI2009-0983), DOS MARES (ref. CTM2010-21810-C03-03), GRACCIE-CONSOLIDER INGENIO 2010 (ref. CSD2007-00067); 2) the Italian Ministry of Agricultural, Food and Forestry Politics-MIPAAF as the HighVision (DM 19177/7303/08); 3) The European Union, as HERMIONE (ref. 226354-HERMIONE), EMSO-PP (grant agreement no.: 211816), the KM3NeT-PP (grant agreement no.: 212525), SESAME (ref. 036949-2) and RTD projects of the VII Framework Programmes which should be equally acknowledged along the CRG Marine Geosciences (grant 2009 SGR 1305) at University of Barcelona (Generalitat of Catalunya); 4) the Canada Foundation for Innovation and the British Columbia Knowledge Development Fund as the NEPTUNE Canada Project. Jacopo Aguzzi is a Postdoctoral Fellow of the Ramón y Cajal Program (MICINN)

In this work we analysed the spatio-temporal variability of discards in the fishery of the deep-sea red shrimp Aristeus antennatus in the northwestern Mediterranean Sea. We sampled fishery discards in the fishing grounds of Palamós (the main harbour for this fishery on the Catalan margin), which are located in several areas of a submarine canyon. We found that the discard ratio in this fishery showed a marked seasonal variability, with a maximum in spring and a minimum in summer. Most of the discarded biomass (almost 96%) were of species with no commercial interest. Within these, the most represented group was elasmobranchs, making up to more than 50% of total discarded biomass. Our findings show that the landing obligation established by the EU will have a low impact in mitigating discards in this fishery, as the vast majority of discards are non-commercial species that are not specified in the regulation. Alternative management strategies, such as a temporary fishery closure in spring (when the discard ratio reaches its maximum), should be considered in order to preserve the vulnerable ecosystem hosted by the submarine canyon. En este estudio se analizó la variabilidad espacio-temporal de los descartes en la pesquería de la gamba roja de profundidad Aristeus antennatus en el mar Mediterráneo Noroccidental. Para ello se muestrearon las capturas obtenidas en los caladeros de Palamós (el mayor puerto para esta pesquería en Cataluña), que están localizados en diferentes áreas adyacentes a un cañón submarino. Nuestros resultados demuestran que la proporción de descartes en las capturas de esta pesquería presenta una marcada variabilidad estacional, con un máximo en primavera y un mínimo en verano. La mayoría de la biomasa de los descartes (casi el 96%) está constituida por especies sin ningún interés comercial. Entre éstas, el grupo más representado es el de los elasmobranquios, que constituye más del 50% de la biomasa total de los descartes. Nuestros resultados indican que la obligación de desembarcar las capturas establecida por la UE tendrá un impacto bajo en disminuir los descartes en esta pesquería, ya que la gran mayoría de los descartes está constituida por especies no comerciales que no están especificadas en la regulación. Medidas de gestión alternativas, como el establecimiento de una veda en primavera (cuando la proporción de descartes llega a su máximo) deberían considerarse para preservar el ecosistema vulnerable de este cañón submarino.

13 páginas,10 figuras, 5 tablas., Within the framework of the multidisciplinary RECS project and with the aim of describing the particleflux transfer from the continental shelf to the deep basin, an array of five mooring lines equipped with a total of five pairs of PPS3/3 sequential-sampling sediment traps and RCM-7/8 current meters were deployed 30 m above the bottom from March 2003 to March 2004 inside and outside the BlanesCanyon. One mooring line was located in the upper canyon at 600 m depth, one in the canyon axis at 1700 m depth and other two close to the canyon walls at 900 m depth. A fifth mooring line was deployed in the continental open slope at 1500 m water depth. The highest near-bottom downward particleflux (14.50 g m−2 d−1) was recorded at the trap located in the upper canyon (M1), where continental inputs associated with the presence of the Tordera River are most relevant. On the other hand, the downward fluxes (4.35 g m−2 d−1) in the canyon axis (M2) were of the same order as those found in the western flank (M3) of the canyon. Both values were clearly higher than the value (1.95 g m−2 d−1) recorded at the eastern canyon wall (M4). The open slope (M5) mass flux (5.42 mg m−2 d−1) recorded by the sediment trap located outside the canyon system was three orders of magnitude lower than the other values registered by the inner canyon stations. The relevance of our data is that it explains how the transport pathway in the canyon occurs through its western flank, where a more active and persistent current toward the open ocean was recorded over the entire year of the experiment. Off-shelf sediment transport along the canyon axis showed clear differences during the period of the study, with some important events leading to strong intensifications of the current coupled with large transport of particlefluxes to the deepest parts of the canyon. Such events are primarily related to increases in river discharge and the occurrence of strong storms and cascading events during the winter. In summary, in this study it is shown that the dynamics of the water masses and the currents in the study area convert the sharp western flank of the BlanesCanyon in a more active region that favors erosion processes than the eastern flank, which has a smoother topography and where the absence of erosional conditions yields to steadier sedimentary processes., D.Z. benefited from a Spanish FPU Grant (AP2000-0524), and MMF was aided by a Juan de la Cierva grant from the Spanish Ministry of Science. Support from the government of Spain and the Fulbright Commission for a post-doctoral fellowship to J.G-O. (ref 2007-0516) is gratefully acknowledged by J. García-Orellana. GRC Geociències Marines was additionally funded by the ‘‘Generalitat de Catalunya’’ through its excellency research groups program (ref. 2005 SGR-00152). This study was also supported by the Spanish national research project RECS (REN2002-04556-C02-01).

[1] The circulation in Blanes canyon, an interruption in the NW Mediterranean continental shelf north of Barcelona, was investigated. The study employs data from oceanographic surveys carried out in the summer and fall of 2003. Velocity data show that in the vicinity of the shelf break the flow is deflected along the canyon walls. A cyclonic mean flow can be seen over the canyon mouth owing to vortex stretching of fluid parcels advected across the shelf break. Field observations are in qualitative agreement with fundamental fluid dynamic considerations based on potential vorticity conservation and friction effects at lateral boundaries. Evidence is given that upwelling is found near the shelf break inside the canyon in the two field experiments. This upwelling extends vertically from the seasonal thermocline (at about 100 m) to the shelf-slope front (at about 200 m). There is no evidence that upwelled water can reach the continental shelf.

13 pages, 5 figures, 2 tables, The spatio-temporal variations in diversity, biomass and abundance of bathyal invertebrates (excluding decapod crustaceans, which have been analysed elsewhere)from the North-western Mediterranean margin are described. The upper canyon (~450 m), middle slope (~650 m) and lower slope (~1,200 m) habitats were investigated throughout the year. The first two sites are visited daily by a specialised commercial fisheries’ fleet, while the deeper site has not been impacted by fishing activities. A total of 140 species from 12 phyla were collected from the 3 study areas. Of these, the Mollusca, Echinodermata, Polychaeta and Cnidaria were the most speciose groups. The patterns of species diversity (H') and evenness (E) were similar in time and space. The upper canyon and middle-slope sites were dominated by echinoderms and molluscs, while the lowerslope site was dominated by cnidarians and sponges. Multifactorial ANOVA showed significant spatio-temporal differences in the biomass and/or abundance only in echinoderms, molluscs, cnidarians and polychaetes. The faunal diVerences observed were explained by habitat type, but not by season. The role of submarine canyons and commercial fishing on shaping the diversity and biomass of bathyal Mediterranean invertebrates is discussed., The data presented here is a result of the RETRO project (CICYT MAR90-757 to FS).

8 pages, 5 figures.-- PMID: 18197243 [PubMed].-- PMCID: PMC2174526.-- Supporting information (Suppl. figures S1-S9) available at: https://doi.org/10.1371/journal.pone.0001431, Dynamics of biological processes on the deep-sea floor are traditionally thought to be controlled by vertical sinking of particles from the euphotic zone at a seasonal scale. However, little is known about the influence of lateral particle transport from continental margins to deep-sea ecosystems. To address this question, we report here how the formation of dense shelf waters and their subsequent downslope cascade, a climate induced phenomenon, affects the population of the deep-sea shrimp Aristeus antennatus. We found evidence that strong currents associated with intense cascading events correlates with the disappearance of this species from its fishing grounds, producing a temporary fishery collapse. Despite this initial negative effect, landings increase between 3 and 5 years after these major events, preceded by an increase of juveniles. The transport of particulate organic matter associated with cascading appears to enhance the recruitment of this deep-sea living resource, apparently mitigating the general trend of overexploitation. Because cascade of dense water from continental shelves is a global phenomenon, we anticipate that its influence on deep-sea ecosystems and fisheries worldwide should be larger than previously thought, Supported by the US Office of Naval Research grant N00014-04-1-0379 (PP; current meter data) and the Spanish Ministerio de Educación y Ciencia grant REN 2002-04151-C02-01 (ML; sediment trap data)