Modeled Buoyancy of eggs and larvae of the deep-sea shrimp Aristeus antennatus (Crustacea: Decapoda) in the northwestern Mediterranean Sea

Information on the buoyancy of eggs and larvae from deep-sea species is rare but necessary for 30 explaining the position of non-swimming larvae in the water column. Due to embryonic 31 morphology and ecology diversities, egg buoyancy has important variations within one species and 32 among other ones. Nevertheless, it has hardly been explored if this buoyancy variability can be a 33 strategy for deep-sea larvae to optimize their transport beyond their spawning areas. In the 34 northwestern Mediterranean Sea, protozoea and mysis larvae of the commercial deep-sea shrimp 35 Aristeus antennatus were recently found in upper layers, but to present, earlier stages like eggs and 36 nauplii have not been collected. Using a Lagrangian transport model and larval characteristics, we 37 evaluate the buoyancy and hydrodynamic effects on the transport of A. antennatus larvae in the 38 northwestern Mediterranean Sea. The transport models suggested that 75% of buoyant eggs 39 released between 500 and 800 m depth (i.e., known spawning area), reached the upper water layers 40 (0-75 m depth). Then, according to the modeled larval drifts, three spawning regions were defined 41 in the studied area: 1) the northern part, along a continental margin crossed by large submarine 42 canyons; 2) the central part, with two circular circulation structures (i.e., eddies); and 3) the 43 southern part, with currents flowing through a channel. The number of larvae in the most upper 44 layer (0-5 m depth) was higher if the larval transport model accounted for the ascent of eggs and 45 nauplii (81%) instead of eggs reaching the surface before hatching (50%). The larvae reaching the 46 most water upper layer (0-5 m depth) had higher rates of dispersal than the ones transported below 47 the surface layer (deeper than 5 m depth). The results of larval dispersal simulations have 48 implications for the understanding of A. antennatus larval ecology and for management decisions 49 related to the shrimp fisheries in the northwestern Mediterranean S

PHEMTO: the polarimetric high energy modular telescope observatory

Based upon dual focusing techniques, the Polarimetric High-Energy Modular Telescope Observatory (PHEMTO) is designed to have performance several orders of magnitude better than the present hard X-ray instruments, in the 1–600 keV energy range. This, together with its angular resolution of around one arcsecond, and its sensitive polarimetry measurement capability, will give PHEMTO the improvements in scientific performance needed for a mission in the 2050 era in order to study AGN, galactic black holes, neutrons stars, and supernovae. In addition, its high performance will enable the study of the non-thermal processes in galaxy clusters with an unprecedented accuracy.Open access funding provided by Istituto Nazionale di Astrofisica within the CRUI-CARE Agreement

Estimating spawning locations of the deep-sea red and blue shrimp Aristeus antennatus (Crustacea: Decapoda) in the northwestern Mediterranean Sea with a backward trajectory model

Ocean Sciences Meeting (OSM), 16-21 February 2020, San Diego, CA, USAThe deep-sea red and blue shrimp Aristeus antennatus is a commercially valuable species for Spanish fishing harbors of the northwestern Mediterranean Sea. Since 2012, some fishermen of the deep-sea shrimp follow a local management plan which restricts fishing in certain areas to sustain the resource. However, little is known about the dispersal of larvae; specifically, it is not known how far larvae can be transported from spawning areas and if there could be mixing of larvae from different fishing grounds. The objective of this study was to estimate the spawning sites of larvae that were collected on a field campaign in 2016, evaluate uncertainty related to model parameterizations, and determine if collected larvae could have come from the restricted fishing areas. Using a 3-dimensional coupled hydrodynamic and Lagrangian transport model, the spawning sites of the larvae were estimated by backwards simulation of larval trajectories from the sampling stations. The backtracked larvae were assigned temperature-dependent stage durations based on a literature review of similar species. Simulated larvae were released from the sampling locations and then were backtracked to spawning sites, with median distances from starting to ending locations of 11 and 38 km when minimum and maximum Pelagic Larval Durations were implemented, respectively. Uncertainty analysis of backward trajectories showed that distance estimates could vary by as much as 27 and 3 km due to differences in how simulated Pelagic Larval Durations and turbulent mixing were parameterized. Of the 35 sampling stations from which larvae were backtracked to fishing grounds, 13 were tracked back to multiple fishing grounds, suggesting that mixing of larvae from different fishing grounds does occur. These results support the idea of multiple connectivities between subpopulations of the A. antennatus and may help inform regional management plansPre-doctoral grants: Spanish Ministry of Economy and Competitiveness (FPI2015: BES-2015-074126) - CONECTA’s project (CTM2014-54648-C2-1-R)Peer reviewe

Modeled buoyancy of eggs and larvae of the deep-sea shrimp Aristeus antennatus (Crustacea: Decapoda) in the northwestern Mediterranean Sea

Este artículo contiene 24 páginas, 9 figuras, 2 tablas.Information on the buoyancy of eggs and larvae from deep-sea species is rare but necessary for explaining the position of non-swimming larvae in the water column. Due to embryonic morphology and ecology diversities, egg buoyancy has important variations within one species and among other ones. Nevertheless, it has hardly been explored if this buoyancy variability can be a strategy for deep-sea larvae to optimize their transport beyond their spawning areas. In the northwestern Mediterranean Sea, protozoea and mysis larvae of the commercial deep-sea shrimp Aristeus antennatus were recently found in upper layers, but to present, earlier stages like eggs and nauplii have not been collected. Using a Lagrangian transport model and larval characteristics, we evaluate the buoyancy and hydrodynamic effects on the transport of A. antennatus’ larvae in the northwestern Mediterranean Sea. The transport models suggested that 75% of buoyant eggs released between 500 and 800 m depth (i.e., known spawning area), reached the upper water layers (0–75 m depth). Then, according to the modeled larval drifts, three spawning regions were defined in the studied area: 1) the northern part, along a continental margin crossed by large submarine canyons; 2) the central part, with two circular circulation structures (i.e., eddies); and 3) the southern part, with currents flowing through a channel. The number of larvae in the most upper layer (0–5 m depth) was higher if the larval transport model accounted for the ascent of eggs and nauplii (81%) instead of eggs reaching the surface before hatching (50%). The larvae reaching the most water upper layer (0–5 m depth) had higher rates of dispersal than the ones transported below the surface layer (deeper than 5 m depth). The results of larval dispersal simulations have implications for the understanding of A. antennatus larval ecology and for management decisions related to the shrimp fisheries in the northwestern Mediterranean Sea.This work was supported by the Ministerio de Economı´a, Industria y Competitividad, Gobierno de España (BES-2015- 074126) to support her PhD within the CONECTA project (CTM2014-54648-C2-1-R) to MC-H.With the funding support of the ‘Severo Ochoa Centre of Excellence’ accreditation (CEX2019-000928-S), of the Spanish Research Agency (AEI)Peer reviewe

Model de deriva larvària de la gamba vermella

V Jornada tècnica sobre la Gamba de Palamós celebrada el 16 de junio de 2018 en la Casa del Mar de PalamósPeer Reviewe

Influence of the Aristeus antennatus larval ecology on simulated dispersal patterns in Nord-Western Mediterranean Sea

The Crustacean Society (TCS) Mid-Year Meeting, 9-22 June 2017, BarcelonaConnectivity patterns among commercial deep-sea shrimp Aristeus antennatus fishing grounds impact the survival of local populations and shape the efficiency set of management strategies. The ecology of early life stages contributes to connectivity among fishery grounds, with spatial displacements driven by both hydrodynamical features and biological adjustment of the extent and the direction of the drift dispersal. Larval drift simulations were conducted with a biophysical model based on predicted eggs abundance map on the Northwest Mediterranean Sea and a predicted pelagic larval duration. To run the simulations, the lack of knowledge on larval behaviour was substituted by simulated drifts using different buoyancies for eggs and nauplius stages and for different patterns of vertical migration at protozoea and mysis stages. As expected, larval dispersion was higher when located near the surface layers, though it decreased with increasing depth up to 100 m depth. Eggs and nauplius with a buoyancy lower than 1.016 gr.m-3, reached the surface within 3 days from 630 m depth, drifting about 135 km in 20 days. The positive buoyancy and the movement of late larval stages at shallow waters explained the larval connectivity among fishing grounds located at relatively large distances, whereas neutral buoyancies together with migration of larvae toward shallow waters explained the connectivity among nearby fishing groundsPeer Reviewe

Modeled buoyancy of eggs and larvae of the deep-sea shrimp Aristeus antennatus (Crustacea: Decapoda) in the northwestern Mediterranean Sea

Information on the buoyancy of eggs and larvae from deep-sea species is rare but necessary for explaining the position of non-swimming larvae in the water column. Due to embryonic morphology and ecology diversities, egg buoyancy has important variations within one species and among other ones. Nevertheless, it has hardly been explored if this buoyancy variability can be a strategy for deep-sea larvae to optimize their transport beyond their spawning areas. In the northwestern Mediterranean Sea, protozoea and mysis larvae of the commercial deep-sea shrimp Aristeus antennatus were recently found in upper layers, but to present, earlier stages like eggs and nauplii have not been collected. Using a Lagrangian transport model and larval characteristics, we evaluate the buoyancy and hydrodynamic effects on the transport of A. antennatus’ larvae in the northwestern Mediterranean Sea. The transport models suggested that 75% of buoyant eggs released between 500 and 800 m depth (i.e., known spawning area), reached the upper water layers (0–75 m depth). Then, according to the modeled larval drifts, three spawning regions were defined in the studied area: 1) the northern part, along a continental margin crossed by large submarine canyons; 2) the central part, with two circular circulation structures (i.e., eddies); and 3) the southern part, with currents flowing through a channel. The number of larvae in the most upper layer (0–5 m depth) was higher if the larval transport model accounted for the ascent of eggs and nauplii (81%) instead of eggs reaching the surface before hatching (50%). The larvae reaching the most water upper layer (0–5 m depth) had higher rates of dispersal than the ones transported below the surface layer (deeper than 5 m depth). The results of larval dispersal simulations have implications for the understanding of A. antennatus larval ecology and for management decisions related to the shrimp fisheries in the northwestern Mediterranean Sea

Contribution of hydrodinamics on passive drifts of Aristeus antennatus particles-like in the North-western Mediterranean Sea

The Crustacean Society (TCS) Mid-Year Meeting, 9-22 June 2017, BarcelonaThe effectiveness of an integrated fishery management plan for the deep sea red shrimp Aristeus antennatus strongly depends on the knowledge about the displacement of individuals during their larval stage among subpopulations from different fishing grounds. To contribute to this purpose, biophysical models were used to study the potential hydrodynamic connectivity among shrimp-fishing grounds along submarine canyons in the North-western Mediterranean Sea using the spawning characteristics of the species. Modelled as passive particles, the larvae followed a main southwest drift along the continental slope and drifted up to 200 km within 31 days. The Cap Creus and Palamòs canyons were inter-connected when particles were released above 600 m depth. Only four percent of the drifters reached the estimated recruitment depth for A. antennatus at about 1,000 m depth when releases of particles took place around 800 m depth. The strength of connectivity between canyons differed with velocity fields from two different hydrodynamic models though the overall connectivity patterns prevailedPeer Reviewe

Influence of the summer deep-sea circulations on passive drifts among the submarine canyons in the northwestern Mediterranean Sea

15 pages, 9 figures, supplement https://doi.org/10.5194/os-15-1745-2019Marine 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 speciesFunding 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 Reviewe

Modeling the spatiotemporal distribution of the deep-sea shrimp Aristeus antennatus (Crustacea: Decapoda) on the northwestern Mediterranean continental margin crossed by submarine canyons

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 reviewe