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Auteur (up) Lopez, J.; Moreno, G.; Lennert-Cody, C.; Maunder, M.; Sancristobal, I.; Caballero, A.; Dagorn, L.
Titre Environmental preferences of tuna and non-tuna species associated with drifting fish aggregating devices (DFADs) in the Atlantic Ocean, ascertained through fishers' echo-sounder buoys Type Article scientifique
Année 2017 Publication Revue Abrégée Deep-Sea Res. Part II-Top. Stud. Oceanogr.
Volume 140 Numéro Pages 127-138
Mots-Clés behavior; catch rates; Echo-sounder buoy; Environmental preferences; equatorial atlantic; fad; floating objects; french-polynesia; gamm; habitat; pacific-ocean; Pelagic fish; Purse seine; thunnus-albacares; Tropical tuna; Tuna; western indian-ocean
Résumé Understanding the relationship between environmental variables and pelagic species concentrations and dynamics is helpful to improve fishery management, especially in a changing environment. Drifting fish aggregating device (DFAD)-associated tuna and non-tuna biomass data from the fishers' echo-sounder buoys operating in the Atlantic Ocean have been modelled as functions of oceanographic (Sea Surface Temperature, Chlorophyll-a, Salinity, Sea Level Anomaly, Thermocline depth and gradient, Geostrophic current, Total Current, Depth) and DFAD variables (DFAD speed, bearing and soak time) using Generalized Additive Mixed Models (GAMMs). Biological interaction (presence of non-tuna species at DFADs) was also included in the tuna model, and found to be significant at this time scale. All variables were included in the analyses but only some of them were highly significant, and variable significance differed among fish groups. In general, most of the fish biomass distribution was explained by the ocean productivity and DFAD-variables. Indeed, this study revealed different environmental preferences for tunas and non-tuna species and suggested the existence of active habitat selection. This improved assessment of environmental and DFAD effects on tuna and non-tuna catchability in the purse seine tuna fishery will contribute to transfer of better scientific advice to regional tuna commissions for the management and conservation of exploited resources.
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ISSN 0967-0645 ISBN Médium
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Numéro d'Appel MARBEC @ alain.herve @ collection 2177
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Auteur (up) Mannocci, L.; Roberts, J.J.; Pedersen, E.J.; Halpin, P.N.
Titre Geographical differences in habitat relationships of cetaceans across an ocean basin Type Article scientifique
Année 2020 Publication Revue Abrégée Ecography
Volume Numéro Pages
Mots-Clés associations; atlantic; conservation; distribution models; diversity; environmental predictors; geographical variation; habitat relationships; highly mobile marine species; marine mammals; North Atlantic Ocean; populations; predator; species distribution modeling; temperature; whales
Résumé The distributions of highly mobile marine species such as cetaceans are increasingly modeled at basin scale by combining data from multiple regions. However, these basin-wide models often overlook geographical variations in species habitat relationships between regions. We tested for geographical variations in habitat relationships for a suite of cetacean taxa between the two sides of the North Atlantic basin. Using cetacean visual survey data and remote sensing data from the western and eastern basin in summer, we related the probability of presence of twelve cetacean taxa from three guilds to seafloor depth, sea surface temperature and primary productivity. In a generalized additive model framework, we fitted 1) basin-wide (BW) models, assuming a single global relationship, 2) region-specific intercepts (RI) models, assuming relationships with the same shape in both regions, but allowing a region-specific intercept and 3) region-specific shape (RS) models, assuming relationships with different shapes between regions. RS models mostly yielded significantly better fits than BW models, indicating cetacean occurrences were better modeled with region-specific than with global relationships. The better fits of RS models over RI models further provided statistical evidence for differences in the shapes of region-specific relationships. Baleen whales showed striking differences in both the shapes of relationships and their mean presence probabilities between regions. Deep diving whales and delphinoids showed contrasting relationships between regions with few exceptions (e.g. non-statistically different shapes of region-specific relationships for harbor porpoise and beaked whales with depth). Our findings stress the need to account for geographical differences in habitat relationships between regions when modeling species distributions from combined data at the basin scale. Our proposed hypotheses offer a roadmap for understanding why habitat relationships may geographically vary in cetaceans and other highly mobile marine species.
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Langue English Langue du Résumé Titre Original
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Volume de collection Numéro de collection Edition
ISSN 0906-7590 ISBN Médium
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Notes WOS:000531110000001 Approuvé pas de
Numéro d'Appel MARBEC @ isabelle.vidal-ayouba @ collection 2792
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Auteur (up) Martinez, E.; Gorgues, T.; Lengaigne, M.; Fontana, C.; Sauzede, R.; Menkes, C.; Uitz, J.; Di Lorenzo, E.; Fablet, R.
Titre Reconstructing Global Chlorophyll-a Variations Using a Non-linear Statistical Approach Type Article scientifique
Année 2020 Publication Revue Abrégée Front. Mar. Sci.
Volume 7 Numéro Pages 464
Mots-Clés climate; decadel variability; equatorial pacific; general-circulation; global scale; indian-ocean; interannual variability; machine learning; marine primary production; north-atlantic; ocean color algorithms; phytoplankton variability; satellite ocean color; seawifs; tropical pacific
Résumé Monitoring the spatio-temporal variations of surface chlorophyll-a concentration (Chl, a proxy of phytoplankton biomass) greatly benefited from the availability of continuous and global ocean color satellite measurements from 1997 onward. These two decades of satellite observations are however still too short to provide a comprehensive description of Chl variations at decadal to multi-decadal timescales. This paper investigates the ability of a machine learning approach (a non-linear statistical approach based on Support Vector Regression, hereafter SVR) to reconstruct global spatio-temporal Chl variations from selected surface oceanic and atmospheric physical parameters. With a limited training period (13 years), we first demonstrate that Chl variability from a 32-years global physical-biogeochemical simulation can generally be skillfully reproduced with a SVR using the model surface variables as input parameters. We then apply the SVR to reconstruct satellite Chl observations using the physical predictors from the above numerical model and show that the Chl reconstructed by this SVR more accurately reproduces some aspects of observed Chl variability and trends compared to the model simulation. This SVR is able to reproduce the main modes of interannual Chl variations depicted by satellite observations in most regions, including El Nino signature in the tropical Pacific and Indian Oceans. In stark contrast with the trends simulated by the biogeochemical model, it also accurately captures spatial patterns of Chl trends estimated by satellite data, with a Chl increase in most extratropical regions and a Chl decrease in the center of the subtropical gyres, although the amplitude of these trends are underestimated by half. Results from our SVR reconstruction over the entire period (1979-2010) also suggest that the Interdecadal Pacific Oscillation drives a significant part of decadal Chl variations in both the tropical Pacific and Indian Oceans. Overall, this study demonstrates that non-linear statistical reconstructions can be complementary tools to in situ and satellite observations as well as conventional physical-biogeochemical numerical simulations to reconstruct and investigate Chl decadal variability.
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Numéro d'Appel MARBEC @ isabelle.vidal-ayouba @ collection 2851
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Auteur (up) Maugars, G.; Manirafasha, M.-C.; Grousset, E.; Boulo, V.; Lignot, J.-H.
Titre The effects of acute transfer to freshwater on ion transporters of the pharyngeal cavity in European seabass (Dicentrarchus labrax) Type Article scientifique
Année 2018 Publication Revue Abrégée Fish Physiol. Biochem.
Volume 44 Numéro 5 Pages 1393-1408
Mots-Clés atlantic salmon; atpase alpha-1 isoforms; branchial chloride cells; carbonic-anhydrase; Dicentrarchus labrax; gill na+/k+-atpase; Gills and extrabranchial organs; Ion transporters; k+-atpase; mitochondrion-rich cells; Osmoregulation; salinity transfer; salmon salmo-salar; seawater acclimation; Seawater to freshwater transfer; Teleost fish
Résumé Gene expression of key ion transporters (the Na+/K+-ATPase NKA, the Na+, K+-2Cl(-) cotransporter NKCC1, and CFTR) in the gills, opercular inner epithelium, and pseudobranch of European seabass juveniles (Dicentrarchus labrax) were studied after acute transfer up to 4days from seawater (SW) to freshwater (FW). The functional remodeling of these organs was also studied. Handling stress (SW to SW transfer) rapidly induced a transcript level decrease for the three ion transporters in the gills and operculum. NKA and CFTR relative expression level were stable, but in the pseudobranch, NKCC1 transcript levels increased (up to 2.4-fold). Transfer to FW induced even more organ-specific responses. In the gills, a 1.8-fold increase for NKA transcript levels occurs within 4days post transfer with also a general decrease for CFTR and NKCC1. In the operculum, transcript levels are only slightly modified. In the pseudobranch, there is a transient NKCC1 increase followed by 0.6-fold decrease and 0.8-fold CFTR decrease. FW transfer also induced a density decrease for the opercular ionocytes and goblet cells. Therefore, gills and operculum display similar trends in SW-fish but have different responses in FW-transferred fish. Also, the pseudobranch presents contrasting response both in SW and in FW, most probably due to the high density of a cell type that is morphologically and functionally different compared to the typical gill-type ionocyte. This pseudobranch-type ionocyte could be involved in blood acid-base regulation masking a minor osmotic regulatory capacity of this organ compared to the gills.
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Langue English Langue du Résumé Titre Original
Éditeur de collection Titre de collection Titre de collection Abrégé
Volume de collection Numéro de collection Edition
ISSN 0920-1742 ISBN Médium
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Notes Approuvé pas de
Numéro d'Appel MARBEC @ alain.herve @ collection 2417
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Auteur (up) McKenzie, D.J.; Palstra, A.P.; Planas, J.; MacKenzie, S.; Begout, M.-L.; Thorarensen, H.; Vandeputte, M.; Mes, D.; Rey, S.; De Boeck, G.; Domenici, P.; Skov, P.V.
Titre Aerobic swimming in intensive finfish aquaculture: applications for production, mitigation and selection Type Article scientifique
Année 2020 Publication Revue Abrégée Rev. Aquac.
Volume Numéro Pages
Mots-Clés aerobic exercise; fatty-acid profile; gilthead sea bream; growth; growth-performance; juvenile atlantic salmon; maturation; oxygen-consumption; postprandial metabolic-response; rainbow-trout; salmon oncorhynchus-tshawytscha; selection; sexual-maturation; stress; sustained exercise; welfare
Résumé We review knowledge on applications of sustained aerobic swimming as a tool to promote productivity and welfare of farmed fish species. There has been extensive interest in whether providing active species with a current to swim against can promote growth. The results are not conclusive but the studies have varied in species, life stage, swimming speed applied, feeding regime, stocking density and other factors. Therefore, much remains to be understood about mechanisms underlying findings of 'swimming-enhanced growth', in particular to demonstrate that swimming can improve feed conversion ratio and dietary protein retention under true aquaculture conditions. There has also been research into whether swimming can alleviate chronic stress, once again on a range of species and life stages. The evidence is mixed but swimming does improve recovery from acute stresses such as handling or confinement. Research into issues such as whether swimming can improve immune function and promote cognitive function is still at an early stage and should be encouraged. There is promising evidence that swimming can inhibit precocious sexual maturation in some species, so studies should be broadened to other species where precocious maturation is a problem. Swimming performance is a heritable trait and may prove a useful selection tool, especially if it is related to overall robustness. More research is required to better understand the advantages that swimming may provide to the fish farmer, in terms of production, mitigation and selection.
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Volume de collection Numéro de collection Edition
ISSN 1753-5123 ISBN Médium
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Notes WOS:000543940500001 Approuvé pas de
Numéro d'Appel MARBEC @ isabelle.vidal-ayouba @ collection 2821
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