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Este artículo contiene 6 páginas, 6 figuras, 4 tablas. ; [EN]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.[ES]La gamba roja, Aristeus antennatus, es uno de los recursos demersales más valorados en Cataluña (noreste de España). Palamós es el puerto pesquero más importante para esta pesquería en la región. Una orden ministerial regulatoria y específica para este puerto, publicada en 2013, estableció la utilización de un copo de malla cuadrada con abertura mínima de 40 mm (40s), reemplazando el copo de malla romboidal de 50 mm (50d) utilizado hasta la fecha. El objetivo era disminuir la cantidad de juveniles en la captura, pero la regulación no consiguió los resultados esperados. En el presente estudio, se midió y comparó la selectividad del copo de 50d y 40s en esta pesquería. Además, se experimentó el uso de una malla cuadrada de 50 mm (50s). Los resultados mostraron que el copo de 40s presentaba una talla de retención del 50% (L50) menor comparado con el copo de 50d, mientras que el de 50s tenía una L50 considerablemente mayor que los demás copos. El análisis de transición mostró un aumento del rendimiento por recluta (Y/R) después del segundo año desde la hipotética implementación del copo de 50s. Nuestra conclusión es que el copo de 40s no tiene una selectividad mayor que el copo de 50d, explicando (por lo menos en parte) la falta de consecución de los objetivos de gestión en la pesquería de gamba de Palamós. En cambio, el copo de 50s mejoraría significativamente a la pesquería, aumentando la selectividad del arte y el Y/R. ; We are grateful for the financial support of the EC Programme Science in Society EC FP7 (ref. 266544-GAP2), the CONECTA research project (ref. CTM2014-54648-C2-1-R) funded by the Spanish Government, the FPU grant of the Spanish Ministry of Education and the Marine Stewardship Council. ; Peer reviewed

Aguzzi, Ernesto . et al. -- 52 pages, 11 figures, 2 tables.-- 50th Year Anniversary Edition ; All marine species studied thus far show rhythmic temporal patterns in their behavioural, physiological, and molecular functions, which are collectively known as biological rhythms. Biological rhythms are generated by biological clocks that time biological functions and are synchronised by geophysical cycles such as the solar light-dark cycle and tidal cycle. On continental margins, behavioural rhythms can be detected by diel (i.e., 24-h based) or seasonal periodical trawling as a consequence of massive inward and outward displacements of populations to and from the sample areas. As a result, significant errors in population/stock and biodiversity assessments performed by trawling may occur if timing of sampling is not taken into account. The increasing number of cabled and permanent multiparametric seafloor observatories now allows direct, continuous, and long-lasting monitoring of benthic ecosystems and analysis in relation to several habitat cycles. This review describes the adaptation of this technology to investigations of rhythmic behaviour by focusing on automated video-imaging. Diel fluctuations in the number of video-observed individuals can be used as a measure of average population rhythmic behaviour. The potential implementation of automated video image analysis in relation to animal tracking and classification procedures based on the combined use of morphometric tools and multivariate statistics is detailed in relation to populational and community studies. Based on video cameras mounted at multiparametric cabled observatories, an integrated time-series analysis protocol using chrono-biomedical procedures is proposed to place video-recorded bio-information in an oceanographic context ; The present work was developed within the framework of five research projects funded by the Spanish Ministry for Science and Innovation (PROMETEO, ref. CTM 2007-66316-C02-02; RITFIM, ref. CTM2010-16274; Operatividad Laboratorio Submarino OB SEA ref. ACI2009-0983; DOS MARES, ref. CTM2010-21810-C03-03; and finally GRACCIE-CONSOL IDER INGENIO 2010, ref. CSD2007-00067) and the Italian Ministry of Agricultural, Food and Forestry Politics-MIPAAF (HighVision, DM 19177/7303/08). The E.U.-funded HERMIONE (ref. 226354-HERMIONE), EMSO-PP (grant agreement no. 211816), the KM3NeT-PP (grant agreement no. 212525), and finally the PERSEUS (CE, VII PM, Grant Agreement no: 287600) RTD projects of the VII Framework Programmes should be equally acknowledged along with the CRG Marine Geosciences (grant 2009 SGR 1305) at the University of Barcelona (Generalitat of Catalunya). Jacopo Aguzzi is a postdoctoral fellow of the Ramón y Cajal Program (MICINN) ; Peer reviewed

14 páginas, 5 tablas, 6 figuras. ; Remote sensing of sea surface temperature (SST) is widely used in climate science because it provides a quasi-synoptic coverage of the ocean. However, the use of these data for near-shore habitats is hindered by the proximity of the coast, therefore further investigation is needed. We compared remote-sensing SST from the MODIS sensor (aboard the Aqua satellite) to near-shore seawater temperature (ST) recorded in situ with data loggers at 5 locations in the western Mediterranean Sea. In situ ST data were collected at 5 m depth over a ~6 yr period and at depths below 5 m at 3 of the locations. We evaluated the suitability of MODIS to represent the temperature at shallow subtidal depths relative to different modes of variability. MODIS reproduced seasonal variability with high correlations (r > 0.98) and biases (0.59 ± 0.03°C) only slightly higher than the accuracy of the loggers (0.50°C). MODIS also captured interannual variability with no systematic biases. When evaluated for intra-seasonal temperature variability, MODIS showed limited biases (up to 0.79°C) with a tendency to overestimate the variability (between 4 and 64%) in both cold and warm seasons. Finally, MODIS over-/underestimated only the most extreme unseasonably cold/warm events (by 1.51 and −0.79°C, respectively). The observed limited differences between the 2 methods can be explained by the particular hydro dynamics of the area and by methodological constraints. Overall, MODIS SST data proved to be a reliable proxy for near-shore ST in the western Mediterranean Sea, and are thus considered suitable for studies requiring temperature reconstruction in shallow near-shore environments. ; The study was funded in part by the Spanish Government through CSI-Coral Project (CGL2013- 43106-R). This is a contribution from the Marine Biogeochemistry and Global Change research group funded by the Catalan Government (2014SGR1029). ; Peer reviewed

13 páginas, 10 figuras, 1 tabla. ; Mid-latitude spring blooms of phytoplankton show considerable year-to-year variability in timing, spatial extent and intensity. It is still unclear to what degree the bloom variability is connected to the magnitude of the vertical flux of organic matter. A coupled three-dimensional hydrodynamic-biogeochemical model is used to relate interannual variability in phytoplankton spring-bloom dynamics to variability in the vertical export of organic matter in the NW Mediterranean Sea. Simulation results from 2001 to 2010, validated against remote-sensing chlorophyll, show marked interannual variability in both timing and shape of the bloom. Model results show a tendency for the bloom to start later after cold and windy winters. However, the onset of the bloom occurs often when the mixed layer is still several hundred metres deep while the heat flux is already approaching zero and turbulent mixing is low. Frequency and intensity of wind episodes control both the timing and development of the bloom and the consequent export flux of organic matter. The wintertime flux is greater than zero and shows relatively low interannual variability. The magnitude of the interannual variability is mainly determined in March when the frequency of windy days positively correlates with the export flux. Frequent wind-driven mixing episodes act to increase the export flux and, at the same time, to interrupt the bloom. Perhaps counterintuitively, our analysis shows that years with discontinuous, low-chlorophyll blooms are likely to have higher export flux than years with intense uninterrupted blooms. The NW Mediterranean shows strong analogy with the North Atlantic section within the same latitude range. Hence, our results may also be applicable to this quantitatively more important area of the world ocean. ; This work was partly funded by the Spanish Ministry of Science and Innovation project "Observation, analysis and modelling of the Mediterranean Sea – OAMMS" CTM2008–03983. The first author (R.B.) would like to thank the Catalan regional government for financial support through the program FI. ; Peer reviewed

Este artículo contiene 9 páginas, 9 figuras, 2 tablas. ; Submarine canyons aggregate numerous marine species and can affect the structure of benthic communities. However, analyses dedicated to assess the spatial distribution variability among several canyons are rare. In the northwestern Mediterranean Sea, three major submarine canyons consecutively indent the narrow margin. There,theabundanceofdeep-seablueandredshrimpAristeusantennatus(Crustacea:Decapoda),oneofthemost important fishery-targeted species in the western and central Mediterranean Sea, sustains relatively high incomes for the nearest fishing harbors. To date, the spatial distribution of this shrimp species has only been assessed on known fishing grounds, but it has neither been modeled simultaneously covering several submarine canyons nor according to the environmental conditions. In this study, we aimed to look over the spatiotemporal shrimp distribution in a region of the northwestern Mediterranean Sea with a particular interest in variations in the three submarine canyons. From summer landing data between 2005 and 2014, we implemented a species distribution model with georeferenced catches linked to environmental data of the shrimp habitats. The model showed that the bottom topography was one of the most essential variables to explain the spatial distribution of the catches and that the highest catch rates were between 475 m and 575 m depth. Overall, two canyons (Blanes and Palamós) sheltered high estimates of catches on the shallow and narrow part of their margins (at 510 and 565 mdepth). Amongthem, 60%ofestimatedsummercatchescamefromthePalamósCanyon, butthisestimate shifted to the Blanes Canyon in summer 2008, probably due to variations in fishing fleet behavior. Modeled hypothetical temperature changes scenarios (to 1 °C warmer than the average) suggested the shrimp catches would decrease lessinthe BlanesCanyon (3% fewercatchesthan the average) than inthePalamós Canyon (20% fewer catches than the average). The information produced by the species distribution model allowed setting spawning locations and depths, which is useful to better understand the canyon influence on benthic communities and to parameterize larval transport models. ; M.C.-H. was fundedby aPhD grant(BES-2015-074126) provided by the Spanish Government. This study was carried out within the Spanish project CONECTA (CTM2014-54648-C2-1-R) lead from theICM-CSIC in Barcelona (ES). ; With the funding support of the 'Severo Ochoa Centre of Excellence' accreditation (CEX2019-000928-S), of the Spanish Research Agency (AEI). ; Peer reviewed

15 pages, 9 figures, supplement https://doi.org/10.5194/os-15-1745-2019 ; Marine biophysical models can be used to explore the displacement of individuals in and between submarine canyons. Mostly, the studies focus on the shallow hydrodynamics in or around a single canyon. In the northwestern Mediterranean Sea, knowledge of the deep-sea circulation and its spatial variability in three contiguous submarine canyons is limited. We used a Lagrangian framework with three-dimensional velocity fields from two versions of the Regional Ocean Modeling System (ROMS) to study the deep-bottom connectivity between submarine canyons and to compare their influence on the particle transport. From a biological point of view, the particles represented eggs and larvae spawned by the deep-sea commercial shrimp Aristeus antennatus along the continental slope in summer. The passive particles mainly followed a southwest drift along the continental slope and drifted less than 200 km considering a pelagic larval duration (PLD) of 31 d. Two of the submarine canyons were connected by more than 27 % of particles if they were released at sea bottom depths above 600 m. The vertical advection of particles depended on the depth where particles were released and the circulation influenced by the morphology of each submarine canyon. Therefore, the impact of contiguous submarine canyons on particle transport should be studied on a case-by-case basis and not be generalized. Because the flows were strongly influenced by the bottom topography, the hydrodynamic model with finer bathymetric resolution data, a less smoothed bottom topography, and finer sigma-layer resolution near the bottom should give more accurate simulations of near-bottom passive drift. Those results propose that the physical model parameterization and discretization have to be considered for improving connectivity studies of deep-sea species ; Funding was provided through the CONECTA project supported by the Ministerio de Economia, Industria y Competividad from the Spanish Government. Morane Clavel-Henry is funded under an FPI PhD program of the Spanish Government (grant no. BES-2015-074126) ; Peer Reviewed

Numerous organisms, including both passive sinkers and active migrators, are captured in sediment traps together with sediments. By capturing these "swimmers", the traps become an extraordinarily tool to obtain relevant information on the biodiversity and dynamics of deep-sea organisms. Here we analyze near-bottom swimmers larger than 500 mm and their fluxes collected from eight near-bottom sediment traps installed on instrumented moorings deployed nearby Blanes Canyon (BC). Our data, obtained from November 2008 to October 2009 with a sampling rate of 15 days, constitutes the first year-long, continuous time series of the whole swimmers' community collected at different traps and bottom depths (from 300 m to 1800 m) inside a submarine canyon and on its adjacent open slope (OS). The traps captured 2155 specimens belonging to 70 taxa, with Crustacea (mainly Copepoda) and Annelida Polychaeta accounting for more than 90% of the total abundance. Almost half of the identified taxa (33) were only present in BC traps, where mean annual swimmer fluxes per trap were almost one order of magnitude higher than in the OS ones. Temporal variability in swimmer fluxes was more evident in BC than in OS. Fluxes dropped in winter (in coincidence with the stormy period in the region) and remained low until the following spring. In spring, there was a switch in taxa composition, including an increase of planktonic organisms. Additionally, we report drastic effects of extreme events, such as major storms, on deep-sea fauna. The impact of such extreme events along submarine canyon systems calls to rethink the influence of climate-driven phenomena on deep-sea ecosystems and, consequently, on their living resources. ; Our research was supported by the PROMETEO research project (Ref. CTM2007- 66316-C02-02/MAR) funded by the Spanish State Research Plan. This is a contribution to the Consolidated Research Group on Marine Benthic Ecology of the "Generalitat de Catalunya" (2014SGR120). CR received an International Outgoing Fellowship from the People Programme (Marie S. Curie Actions) of the European Union's Seventh Framework Programme (FP7/2007-2013) (www.DeepFall-project.eu) under the REA grant agreement N. PIOF-GA-2013-628146. ; Peer reviewed

14 pages, 2 figures ; The deep sea (i.e., >200 m depth) is a highly dynamic environment where benthic ecosystems are functionally and ecologically connected with the overlying water column and the surface. In the aphotic deep sea, organisms rely on external signals to synchronize their biological clocks. Apart from responding to cyclic hydrodynamic patterns and periodic fluctuations of variables such as temperature, salinity, phytopigments, and oxygen concentration, the arrival of migrators at depth on a 24-h basis (described as Diel Vertical Migrations; DVMs), and from well-lit surface and shallower waters, could represent a major response to a solar-based synchronization between the photic and aphotic realms. In addition to triggering the rhythmic behavioral responses of benthic species, DVMs supply food to deep seafloor communities through the active downward transport of carbon and nutrients. Bioluminescent species of the migrating deep scattering layers play a not yet quantified (but likely important) role in the benthopelagic coupling, raising the need to integrate the efficient detection and quantification of bioluminescence into large-scale monitoring programs. Here, we provide evidence in support of the benefits for quantifying and continuously monitoring bioluminescence in the deep sea. In particular, we recommend the integration of bioluminescence studies into long-term monitoring programs facilitated by deep-sea neutrino telescopes, which offer photon counting capability. Their Photo-Multiplier Tubes and other advanced optical sensors installed in neutrino telescope infrastructures can boost the study of bioluminescent DVMs in concert with acoustic backscatter and video imagery from ultra-low-light cameras. Such integration will enhance our ability to monitor proxies for the mass and energy transfer from the upper ocean into the deep-sea Benthic Boundary Layer (BBL), a key feature of the ocean biological pump and crucial for monitoring the effects of climate-change. In addition, it will allow for investigating the role of deep scattering DVMs in the behavioral responses, abundance and structure of deep-sea benthic communities. The proposed approach may represent a new frontier for the study and discovery of new, taxon-specific bioluminescence capabilities. It will thus help to expand our knowledge of poorly described deep-sea biodiversity inventories and further elucidate the connectivity between pelagic and benthic compartments in the deep-sea ; This work was developed within the framework of the Tecnoterra (ICM-CSIC/UPC) and the following project activities: ARIM (Autonomous Robotic sea-floor Infrastructure for benthopelagic Monitoring; MartTERA ERA-Net Cofound) and RESBIO (TEC2017-87861-R; Ministerio de Ciencia, Innovación y Universidades; PIs: JR and JA) and with funding from the Spanish government through the 'Severo Ochoa Centre of Excellence' accreditation (CEX2019-000928-S). Ocean Networks Canada was funded through Canada Foundation for Innovation-Major Science Initiative Fund 30199 to FD and BP. The STRAW and STRAW-b experiments deployed and connected through the NEPTUNE cabled observatory are supported by the German Research Foundation through grant SFB 1258 "Neutrinos and Dark Matter in Astro- and Particle Physics," the cluster of excellence "Origin and Structure of the Universe," and the University of Alberta

15 pages, 4 figures, supplementary material https://doi.org/10.1093/icesjms/fsaa169.-- There are no new data associated with this article. No new datawere generated or analysed in support of this research ; Seafloor multiparametric fibre-optic-cabled video observatories are emerging tools for standardized monitoring programmes, dedicated to the production of real-time fishery-independent stock assessment data. Here, we propose that a network of cabled cameras can be set up and optimized to ensure representative long-term monitoring of target commercial species and their surrounding habitats. We highlight the importance of adding the spatial dimension to fixed-point-cabled monitoring networks, and the need for close integration with Artificial Intelligence pipelines, that are necessary for fast and reliable biological data processing. We then describe two pilot studies, exemplary of using video imagery and environmental monitoring to derive robust data as a foundation for future ecosystem-based fish-stock and biodiversity management. The first example is from the NE Pacific Ocean where the deep-water sablefish (Anoplopoma fimbria) has been monitored since 2010 by the NEPTUNE cabled observatory operated by Ocean Networks Canada. The second example is from the NE Atlantic Ocean where the Norway lobster (Nephrops norvegicus) is being monitored using the SmartBay observatory developed for the European Multidisciplinary Seafloor and water column Observatories. Drawing from these two examples, we provide insights into the technological challenges and future steps required to develop full-scale fishery-independent stock assessments ; This work was funded by the following project activities: ARIM (Autonomous Robotic sea-floor Infrastructure for benthopelagic Monitoring; MartTERA ERA-Net Cofound), ARCHES (Autonomous Robotic Networks to Help Modern Societies; German Helmholtz Association), RESBIO (TEC2017-87861-R; Ministerio de Ciencia, Innovación y Universidades, Spanish Government), RESNEP (CTM2017-82991-C2-1-R; Ministerio de Ciencia, Innovación y Universidades, Spanish Government), and SmartLobster (EMSO-LINK Trans National Access-TNA). The EMSO_SmartBay cabled observatory was funded by Science Foundation Ireland (SFI) as part of a SFI Research Infrastructure Award Grant No. 12/RI/2331 ; With the funding support of the 'Severo Ochoa Centre of Excellence' accreditation (CEX2019-000928-S), of the Spanish Research Agency (AEI)