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Auteur Lefevre, S.; Mckenzie, D.J.; Nilsson, G.E. doi  openurl
  Titre Models projecting the fate of fish populations under climate change need to be based on valid physiological mechanisms Type Article scientifique
  Année 2017 Publication Revue Abrégée Glob. Change Biol.  
  Volume 23 Numéro 9 Pages 3449-3459  
  Mots-Clés aerobic scope; coryphaena-hippurus; energy-demand teleosts; gadus-morhua l; gill surface area; growth; makaira-nigricans; marlin tetrapturus-albidus; metabolism; metabolism-size relationship; oxygen consumption; oxygen-consumption; ram ventilation; Respiration; scaling; swimming performance; tuna katsuwonus-pelamis  
  Résumé Some recent modelling papers projecting smaller fish sizes and catches in a warmer future are based on erroneous assumptions regarding (i) the scaling of gills with body mass and (ii) the energetic cost of 'maintenance'. Assumption (i) posits that insurmountable geometric constraints prevent respiratory surface areas from growing as fast as body volume. It is argued that these constraints explain allometric scaling of energy metabolism, whereby larger fishes have relatively lower mass-specific metabolic rates. Assumption (ii) concludes that when fishes reach a certain size, basal oxygen demands will not be met, because of assumption (i). We here demonstrate unequivocally, by applying accepted physiological principles with reference to the existing literature, that these assumptions are not valid. Gills are folded surfaces, where the scaling of surface area to volume is not constrained by spherical geometry. The gill surface area can, in fact, increase linearly in proportion to gill volume and body mass. We cite the large body of evidence demonstrating that respiratory surface areas in fishes reflect metabolic needs, not vice versa, which explains the large interspecific variation in scaling of gill surface areas. Finally, we point out that future studies basing their predictions on models should incorporate factors for scaling of metabolic rate and for temperature effects on metabolism, which agree with measured values, and should account for interspecific variation in scaling and temperature effects. It is possible that some fishes will become smaller in the future, but to make reliable predictions the underlying mechanisms need to be identified and sought elsewhere than in geometric constraints on gill surface area. Furthermore, to ensure that useful information is conveyed to the public and policymakers about the possible effects of climate change, it is necessary to improve communication and congruity between fish physiologists and fisheries scientists.  
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  Volume de collection (down) Numéro de collection Edition  
  ISSN 1354-1013 ISBN Médium  
  Région Expédition Conférence  
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  Numéro d'Appel MARBEC @ alain.herve @ collection 2169  
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Auteur Nikolic, N.; Lauretta, M.; Patucca, A.; Morandeau, G. doi  openurl
  Titre Characterization and standardization of the Atlantic albacore French pelagic trawl fishery Type Article scientifique
  Année 2018 Publication Revue Abrégée Aquat. Living Resour.  
  Volume 31 Numéro Pages 31  
  Mots-Clés Albacore; Atlantic; behavior; catch; catch rates; fisheries; habitat; migration; north pacific albacore; ocean; stock; thunnus-alalunga; trawl; tuna  
  Résumé We compiled and analysed logbook data from the French trawl albacore fishery covering the period 1991-2015. The dataset comprised catch and effort data for the French fleet operating in the Bay of Biscay and Celtic Sea, as well as spatiotemporal and gear characteristics. Generalized linear modelling was used to model spatial, seasonal, environmental, and gear covariates of fleet CPUE rates. A long-term index of relative abundance is provided that can be integrated into the stock assessment of North Atlantic albacore. The analysis revealed higher albacore CPUE associated with relatively low sea surface temperature and distinct seasonal effects. The derived abundance trend for the French trawl fishery agreed with the estimated time series of stock abundance from recent assessments.  
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  Volume de collection (down) Numéro de collection Edition  
  ISSN 0990-7440 ISBN Médium  
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  Numéro d'Appel MARBEC @ alain.herve @ collection 2426  
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Auteur Navarro, J.; Saez-Liante, R.; Albo-Puigserver, M.; Coll, M.; Palomera, I. doi  openurl
  Titre Feeding strategies and ecological roles of three predatory pelagic fish in the western Mediterranean Sea Type Article scientifique
  Année 2017 Publication Revue Abrégée Deep-Sea Res. Part II-Top. Stud. Oceanogr.  
  Volume 140 Numéro Pages 9-17  
  Mots-Clés diet; ecosystem structure; iberian peninsula; indian-ocean; isotope ratios; Marine predators; Pelagic ecosystem; Stable isotopes; stable-isotopes; Stomach contents; swordfish; top predators; Trophic ecology; trophic level; xiphias-gladius; Yellowfin tuna  
  Résumé Knowing the feeding ecology of marine predators is pivotal to developing an understanding of their ecological role in the ecosystem and determining the trophic relationships between them. Despite the ecological importance of predatory pelagic fish species, research on these species in the Mediterranean Sea is limited. Here, by combining analyses of stomach contents and stable isotope values, we examined the feeding strategies of swordfish, Xiphias gladius, little tunny, Euthynnus alletteratus and Atlantic bonito, Sarda sarda, in the western Mediterranean Sea. We also compared the trophic niche and trophic level of these species with published information of other sympatric pelagic predators present in the ecosystem. Results indicated that, although the diet of the three species was composed mainly by fin-fish species, a clear segregation in their main feeding strategies was found. Swordfish showed a generalist diet including demersal species such as blue whiting, Micromesistius poutassou, and European hake, Merluccius merluccius, and pelagic fin-fish such as barracudina species (Arctozenus risso and Lestidiops jayakari) or small pelagic fish species. Little tunny and Atlantic bonito were segregated isotopically between them and showed a diet basically composed of anchovy, Engraulis encrasicolus, and round sardinella, Sardinella aurita, and sardines, Sardina pilchardus, respectively. This trophic segregation, in addition to potential segregation by depth, is likely a mechanism that allows their potential coexistence within the same pelagic habitat. When the trophic position of these three predatory pelagic fish species is compared with other pelagic predators such as bluefin tuna, Thunnus thynnus, and dolphinfish, Coryphaena hippurus, present in the western Mediterranean Sea, we found that they show similar intermediate trophic position in the ecosystem. In conclusion, the combined stomach and isotopic results highlight, especially for little tunny and Atlantic bonito, the trophic importance of Clupeoid species in their diet. In addition, the importance of demersal resources for swordfish provides evidence for the pelagic-demersal coupling of the ecosystem and the need to manage marine resources in an integrated way. (C) 2016 Elsevier Ltd. All rights reserved.  
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  Volume de collection (down) Numéro de collection Edition  
  ISSN 0967-0645 ISBN Médium  
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  Numéro d'Appel MARBEC @ alain.herve @ collection 2175  
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Auteur Lopez, J.; Moreno, G.; Lennert-Cody, C.; Maunder, M.; Sancristobal, I.; Caballero, A.; Dagorn, L. doi  openurl
  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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  Langue English Langue du Résumé Titre Original  
  Éditeur de collection Titre de collection Titre de collection Abrégé  
  Volume de collection (down) Numéro de collection Edition  
  ISSN 0967-0645 ISBN Médium  
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  Numéro d'Appel MARBEC @ alain.herve @ collection 2177  
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Auteur Briscoe, D.K.; Hobday, A.J.; Carlisle, A.; Scales, K.; Eveson, J.P.; Arrizabalaga, H.; Druon, J.N.; Fromentin, J.-M. doi  openurl
  Titre Ecological bridges and barriers in pelagic ecosystems Type Article scientifique
  Année 2017 Publication Revue Abrégée Deep-Sea Res. Part II-Top. Stud. Oceanogr.  
  Volume 140 Numéro Pages 182-192  
  Mots-Clés arctic marine mammals; atlantic bluefin tuna; Billfish; Brazilian episode; climate-change; el-nino; interannual variation; Marine mammal; marlin makaira-nigricans; Migration corridors; Oceanographic features; population connectivity; satellite archival tags; sea-turtles; site fidelity; species distribution; thunnus-maccoyii; Tuna  
  Résumé Many highly mobile species are known to use persistent pathways or corridors to move between habitat patches in which conditions are favorable for particular activities, such as breeding or foraging. In the marine realm, environmental variability can lead to the development of temporary periods of anomalous oceanographic conditions that can connect individuals to areas of habitat outside a population's usual range, or alternatively, restrict individuals from areas usually within their range, thus acting as ecological bridges or ecological barriers. These temporary features can result in novel or irregular trophic interactions and changes in population spatial dynamics, and, therefore, may have significant implications for management of marine ecosystems. Here, we provide evidence of ecological bridges and barriers in different ocean regions, drawing upon five case studies in which particular oceanographic conditions have facilitated or restricted the movements of individuals from highly migratory species. We discuss the potential population-level significance of ecological bridges and barriers, with respect to the life history characteristics of different species, and inter- and intra-population variability in habitat use. Finally, we summarize the persistence of bridge dynamics with time, our ability to monitor bridges and barriers in a changing climate, and implications for forecasting future climate mediated ecosystem change.  
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  Langue English Langue du Résumé Titre Original  
  Éditeur de collection Titre de collection Titre de collection Abrégé  
  Volume de collection (down) Numéro de collection Edition  
  ISSN 0967-0645 ISBN Médium  
  Région Expédition Conférence  
  Notes Approuvé pas de  
  Numéro d'Appel MARBEC @ alain.herve @ collection 2178  
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