|   | 
Détails
   web
Enregistrements
Auteur Keller, S.; Quetglas, A.; Puerta, P.; Bitetto, I.; Casciaro, L.; Cuccu, D.; Esteban, A.; Garcia, C.; Garofalo, G.; Guijarro, B.; Josephides, M.; Jadaud, A.; Lefkaditou, E.; Maiorano, P.; Manfredi, C.; Marceta, B.; Micallef, R.; Peristeraki, P.; Relini, G.; Sartor, P.; Spedicato, M.T.; Tserpes, G.; Hidalgo, M.
Titre Environmentally driven synchronies of Mediterranean cephalopod populations Type Article scientifique
Année 2017 Publication Revue Abrégée Prog. Oceanogr.
Volume 152 Numéro Pages 1-14
Mots-Clés atlantic bluefin tuna; balearic sea; Cephalopods; Dynamic factor analysis; ecological niche approach; fisheries; fluctuations; hake merluccius-merluccius; Illex coindetii; life-history; Mediterranean; medits; octopus; Octopus vulgaris; squid; Synchrony; time-series
Résumé The Mediterranean Sea is characterized by large scale gradients of temperature, productivity and salinity, in addition to pronounced mesoscale differences. Such a heterogeneous system is expected to shape the population dynamics of marine species. On the other hand, prevailing environmental and climatic conditions at whole basin scale may force spatially distant populations to fluctuate in synchrony. Cephalopods are excellent case studies to test these hypotheses owing to their high sensitivity to environmental conditions. Data of two cephalopod species with contrasting life histories (benthic octopus vs nectobenthic squid), obtained from scientific surveys carried out throughout the Mediterranean during the last 20 years were analyzed. The objectives of this study and the methods used to achieve them (in parentheses) were: (i) to investigate synchronies in spatially separated populations (decorrelation analysis); (ii) detect underlying common abundance trends over distant regions (dynamic factor analysis, DFA); and (iii) analyse putative influences of key environmental drivers such as productivity and sea surface temperature on the population dynamics at regional scale (general linear models, GLM). In accordance with their contrasting spatial mobility, the distance from where synchrony could no longer be detected (decorrelation scale) was higher in squid than in octopus (349 vs 217 km); for comparison, the maximum distance between locations was 2620 km. The DFA revealed a general increasing trend in the abundance of both species in most areas, which agrees with the already reported worldwide proliferation of cephalopods. DFA results also showed that population dynamics are more similar in the eastern than in the western Mediterranean basin. According to the GLM models, cephalopod populations were negatively affected by productivity, which would be explained by an increase of competition and predation by fishes. While warmer years coincided with declining octopus numbers, areas of high sea surface temperature showed higher densities of squid. Our results are relevant for regional fisheries management and demonstrate that the regionalisation objectives envisaged under the new Common Fishery Policy may not be adequate for Mediterranean cephalopod stocks. (C) 2017 Elsevier Ltd. All rights reserved.
Adresse
Auteur institutionnel Thèse
Editeur Lieu de Publication Éditeur
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 0079-6611 ISBN Médium
Région Expédition Conférence
Notes Approuvé pas de
Numéro d'Appel MARBEC @ alain.herve @ collection (down) 2132
Lien permanent pour cet enregistrement
 

 
Auteur Bodin, N.; Lesperance, D.; Albert, R.; Hollanda, S.; Michaud, P.; Degroote, M.; Churlaud, C.; Bustamante, P.
Titre Trace elements in oceanic pelagic communities in the western Indian Ocean Type Article scientifique
Année 2017 Publication Revue Abrégée Chemosphere
Volume 174 Numéro Pages 354-362
Mots-Clés atlantic-ocean; blue marlin; Environmental risk assessment; makaira-nigricans; Marine fish; Mediterranean Sea; Mercury; mercury content; North Pacific; risk-assessment; Seafood; Selenium; swordfish xiphias-gladius; Tuna fisheries' bycatch
Résumé The mineral composition of target and non-target pelagic fish caught by purse-seiners and longliners in the western-central Indian Ocean was determined. From the 10 essential elements analysed, selenium and zinc showed the highest concentrations in swordfish and blue marlin while Indian mackerel appeared as a good source of copper, iron and chrome. All catch had levels of lead and cadmium, two toxic elements, below the maximum sanitary limits. Although some concerns were raised regarding mercury concentrations in the largest species (wahoo, swordfish and blue marlin), molar ratios of mercury and selenium indicate that all oceanic pelagic fish from the western-central Indian Ocean are safe for human consumption. This study also gives insights on the relationships between the levels of essential and toxic elements in fish muscle and the size, trophic position and diet sources of the studied pelagic species. (C) 2017 Elsevier Ltd. All rights reserved.
Adresse
Auteur institutionnel Thèse
Editeur Lieu de Publication Éditeur
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 0045-6535 ISBN Médium
Région Expédition Conférence
Notes Approuvé pas de
Numéro d'Appel MARBEC @ alain.herve @ collection (down) 2119
Lien permanent pour cet enregistrement
 

 
Auteur Escalle, L.; Gaertner, D.; Chavance, P.; Delgado de Molina, A.; Ariz, J.; Mérigot, B.
Titre Forecasted consequences of simulated FAD moratoria in the Atlantic and Indian Oceans on catches and bycatches Type Article scientifique
Année 2017 Publication Revue Abrégée ICES J. Mar. Sci.
Volume 74 Numéro 3 Pages 780-792
Mots-Clés area; Bycatch; ecosystem approach to fisheries; fish aggregation device; management; Megafauna; Monte Carlo simulations; Purse-seine fishery; time; time-area restriction; tropical tuna purse-seine fishery; Tuna
Résumé Given the increasingly extensive use of drifting fish aggregation devices (FADs) by the purse-seine fisheries targeting tropical tunas, fishing effort restrictions have been introduced to manage tropical tuna stocks. However, these measures are focused on the protection of juvenile tunas and do not take account of the potential impact on bycatch or associated megafauna (whales and whale sharks). An iterative “fishing-day” Monte Carlo simulation model was developed to investigate the consequences on tropical tunas and bycatch of introducing extensive area 6-month moratoria on FAD activities. The model allowed for variability in a range of plausible values of the parameters characterizing the fishing operations conducted by European purse-seiners in the eastern tropical Atlantic and western Indian Oceans for the period 2005-2014. Monte Carlo simulations, using probabilities based on these fishery data, were carried out for the French and Spanish fishing fleets separately to account for differences in fishing strategies. The models predicted a decrease in FAD sets and an increase in free school sets. As a consequence, the catch of small tuna (<10 kg) decreased while the catch of large tuna (>= 10 kg) increased, leading to an overall increase in tuna catch of 100-200 tons/year/vessel in the Atlantic Ocean, and a decrease of 400-1500 tons/year/vessel in the Indian Ocean. The bycatch decreased in the Indian Ocean, while in the Atlantic Ocean billfishes, turtles and chondrichthyans bycatch increased slightly and other bony fishes decreased. Because fishing practices were modified, whale and whale shark associated sets increased slightly in the Indian Ocean.
Adresse
Auteur institutionnel Thèse
Editeur Lieu de Publication Éditeur
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 1054-3139 ISBN Médium
Région Expédition Conférence
Notes Approuvé pas de
Numéro d'Appel MARBEC @ alain.herve @ collection (down) 2105
Lien permanent pour cet enregistrement
 

 
Auteur Mullon, C.; Guillotreau, P.; Galbraith, E.D.; Fortilus, J.; Chaboud, C.; Bopp, L.; Aumont, O.; Kaplan, D.
Titre Exploring future scenarios for the global supply chain of tuna Type Article scientifique
Année 2017 Publication Revue Abrégée Deep Sea Research Part II: Topical Studies in Oceanography
Volume 140 Numéro Pages 251-267
Mots-Clés climate change; Global supply chain; marine protected area; Scenarios; Tuna
Résumé The abundance of tuna, an important top predator that ranges throughout tropical and subtropical oceans, is now largely determined by fishing activity. Fishing activity, in turn, is determined by the interaction of fish availability, fishing capacity, fishing costs and global markets for tuna products. In the face of overfishing, the continued sustainable supply of tuna is likely to require improved global governance, that would benefit from modeling frameworks capable of integrating market forces with the availability of fish in order to consider alternative future projections. Here we describe such a modeling framework, in which we develop several simple, contrasting scenarios for the development of the tuna supply chain in order to illustrate the utility of the approach for global evaluation of management strategies for tuna and other complex, stock-structured fisheries. The model includes multiple national and multi-national fishing fleets, canneries and fresh/frozen markets, and connects these to global consumers using a network of flows. The model is calibrated using recent data on fish catch, cannery and fresh/frozen production, and consumption. Scenarios explore the control on future outcomes in the global tuna fishery by representing, in a simple way, the effects of (1) climate change, (2) changes in the global demand for tuna, and (3) changes in the access to fishing grounds (marine reserves). The results emphasize the potential importance of increasing demand in provoking a global collapse, and suggest that controlling tuna production by limiting technical efficiency is a potential countermeasure. Finally we discuss the outcomes in terms of potential extensions of the scenario approach allowed by this global network model of the tuna supply chain.
Adresse
Auteur institutionnel Thèse
Editeur Lieu de Publication Éditeur
Langue Langue du Résumé Titre Original
Éditeur de collection Titre de collection Titre de collection Abrégé
Volume de collection Numéro de collection Edition
ISSN 0967-0645 ISBN Médium
Région Expédition Conférence
Notes Approuvé pas de
Numéro d'Appel MARBEC @ isabelle.vidal-ayouba @ collection (down) 2098
Lien permanent pour cet enregistrement
 

 
Auteur Pons, M.; Branch, T.A.; Melnychuk, M.C.; Jensen, O.P.; Brodziak, J.; Fromentin, J.M.; Harley, S.J.; Haynie, A.C.; Kell, L.T.; Maunder, M.N.; Parma, A.M.; Restrepo, V.R.; Sharma, R.; Ahrens, R.; Hilborn, R.
Titre Effects of biological, economic and management factors on tuna and billfish stock status Type Article scientifique
Année 2017 Publication Revue Abrégée Fish Fish
Volume 18 Numéro 1 Pages 1-21
Mots-Clés Fisheries management; marine conservation; stock assessment; stock status; Tuna fisheries
Résumé Commercial tunas and billfishes (swordfish, marlins and sailfish) provide considerable catches and income in both developed and developing countries. These stocks vary in status from lightly exploited to rebuilding to severely depleted. Previous studies suggested that this variability could result from differences in life-history characteristics and economic incentives, but differences in exploitation histories and management measures also have a strong effect on current stock status. Although the status (biomass and fishing mortality rate) of major tuna and billfish stocks is well documented, the effect of these diverse factors on current stock status and the effect of management measures in rebuilding stocks have not been analysed at the global level. Here, we show that, particularly for tunas, stocks were more depleted if they had high commercial value, were long-lived species, had small pre-fishing biomass and were subject to intense fishing pressure for a long time. In addition, implementing and enforcing total allowable catches (TACs) had the strongest positive influence on rebuilding overfished tuna and billfish stocks. Other control rules such as minimum size regulations or seasonal closures were also important in reducing fishing pressure, but stocks under TAC implementations showed the fastest increase of biomass. Lessons learned from this study can be applied in managing large industrial fisheries around the world. In particular, tuna regional fisheries management organizations should consider the relative effectiveness of management measures observed in this study for rebuilding depleted large pelagic stocks.
Adresse
Auteur institutionnel Thèse
Editeur Lieu de Publication Éditeur
Langue en Langue du Résumé Titre Original
Éditeur de collection Titre de collection Titre de collection Abrégé
Volume de collection Numéro de collection Edition
ISSN 1467-2979 ISBN Médium
Région Expédition Conférence
Notes Approuvé pas de
Numéro d'Appel MARBEC @ isabelle.vidal-ayouba @ collection (down) 2079
Lien permanent pour cet enregistrement