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Auteur Mariani, P.; Křivan, V.; MacKenzie, B.R.; Mullon, C. url  doi
openurl 
  Titre The migration game in habitat network: the case of tuna Type Article scientifique
  Année 2016 Publication Revue Abrégée Theor Ecol  
  Volume 9 Numéro 2 Pages 219-232  
  Mots-Clés Bluefin tuna; Game theory; Habitat selection; Ideal free distribution; Plant Sciences; Structured population; Theoretical Ecology/Statistics; Zoology  
  Résumé (up) Long-distance migration is a widespread process evolved independently in several animal groups in terrestrial and marine ecosystems. Many factors contribute to the migration process and of primary importance are intra-specific competition and seasonality in the resource distribution. Adaptive migration in direction of increasing fitness should lead to the ideal free distribution (IFD) which is the evolutionary stable strategy of the habitat selection game. We introduce a migration game which focuses on migrating dynamics leading to the IFD for age-structured populations and in time varying habitats, where dispersal is costly. The model predicts migration dynamics between these habitats and the corresponding population distribution. When applied to Atlantic bluefin tunas, it predicts their migration routes and their seasonal distribution. The largest biomass is located in the spawning areas which have also the largest diversity in the age-structure. Distant feeding areas are occupied on a seasonal base and often by larger individuals, in agreement with empirical observations. Moreover, we show that only a selected number of migratory routes emerge as those effectively used by tunas.  
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  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 1874-1738, 1874-1746 ISBN Médium  
  Région Expédition Conférence  
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  Numéro d'Appel MARBEC @ isabelle.vidal-ayouba @ collection 1465  
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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 (up) 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 Numéro de collection Edition  
  ISSN 0967-0645 ISBN Médium  
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  Numéro d'Appel MARBEC @ alain.herve @ collection 2178  
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Auteur Robinson, J.; Guillotreau, P.; Jimenez-Toribio, R.; Lantz, F.; Nadzon, L.; Dorizo, J.; Gerry, C.; Marsac, F. url  doi
openurl 
  Titre Impacts of climate variability on the tuna economy of Seychelles Type Article scientifique
  Année 2010 Publication Revue Abrégée Climate Research  
  Volume 43 Numéro Pages 149-162  
  Mots-Clés climate; economy; Enso; fisheries; Seychelles; tuna; variability  
  Résumé (up) Many small island states have developed economies that are strongly dependent on tuna fisheries. Consequently, they are vulnerable to the socio-economic effects of climate change and variability, processes that are known to impact tuna fisheries distribution and productivity. The aim of this study was to assess the impacts of climate oscillations on the tuna-dependent economy of Seychelles. Using a multiplier approach, the direct, indirect and induced economic effects of the tuna industry expenditure benefiting the Seychelles' economy declined in 1998 by 58, 26 and 35%, respectively (mean decline: 42%), a year of strong climate oscillation in the western Indian Ocean. Multivariate patterns in tuna purse-seine vessel expenditures in port were substantially modified by strong climate oscillations, particularly in 1998. A cointegration time-series model predicted that a 40% decline in tuna landings and transhipment in Port Victoria, a value commensurate with that observed in 1998, would result in a 34% loss for the local economy solely through reductions in cargo handling expenditures. Of several indices tested, the Indian Oscillation Index was best at predicting the probability of switching between low and high regimes of landings and transhipment, which translate into impacts for the economy. It is hypothesised that a late 2006/early 2007 climate oscillation was compounded by prior overfishing to produce a stronger impact on the fishery and economy of Seychelles. The effects of fishing and climate variability on tuna fisheries are complex and pose significant challenges for fisheries management and the economic development of countries in the Indian Ocean.  
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  ISSN 0936-577x ISBN Médium  
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  Numéro d'Appel LL @ pixluser @ collection 101  
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Auteur Guyader, O.; Robert, B.; Lionel, R. doi  openurl
  Titre Assessing the number of moored fishing aggregating devices through aerial surveys: A case study from Guadeloupe Type Article scientifique
  Année 2017 Publication Revue Abrégée Fish Res.  
  Volume 185 Numéro Pages 73-82  
  Mots-Clés abundance; Aerial survey; behavior; Dolphinfish; fads; Fish aggregating devices (FAD); fisheries; floating objects; islands; knowledge; management; Small-scale fisheries management; transect surveys; yellowfin; Yellowfin tuna  
  Résumé (up) Moored fish aggregating devices (MFADs) are increasingly being used in small-scale tropical fisheries to access pelagic fish species that are otherwise difficult to harvest in large numbers. Little attention has yet been paid to monitoring MFADs in coastal areas, however. This is most likely due to the small-scale nature of most fisheries that utilize them and the presumed lower impact of those fisheries on fish stocks and their ecosystems. In this paper, we examined the abundance and density of MFADs around Guadeloupe, using aerial line transect surveys. Estimated MFAD densities were found to be high compared with previously reported densities in this area, especially within the 22-45 km range offshore. We examine and discuss possible reasons for these high densities. The main drivers appear to be the target species dolphinfish (Coryphaena hippurus) and yellowfin tuna (Thunnus albacares) and related fishing behaviour. We present different approaches for reducing and monitoring MFADs densities, including the co-management of MFAD territorial use rights by fishing communities. (C) 2016 Elsevier B.V. All rights reserved.  
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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 0165-7836 ISBN Médium  
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  Numéro d'Appel MARBEC @ alain.herve @ collection 1696  
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Auteur Rouyer, T.; Bonhommeau, S.; Giordano, N.; Ellul, S.; Ellul, G.; Deguara, S.; Wendling, B.; Belhaj, M.M.; Kerzerho, V.; Bernard, S. url  doi
openurl 
  Titre Tagging Atlantic bluefin tuna from a farming cage: An attempt to reduce handling times for large scale deployments Type Article scientifique
  Année 2019 Publication Revue Abrégée Fisheries Research  
  Volume 211 Numéro Pages 27-31  
  Mots-Clés Electronic tagging; Farming cage; Large Atlantic bluefin tuna; Release  
  Résumé (up) Our knowledge on the biology and ecology of marine species have improved greatly through the use of archival tags by enabling the collection on information from individual in the wild. This is specifically true for large pelagic species such as the Atlantic Bluefin tuna (ABFT, Thunnus thynnus) where, for the first time, it has been possible to confirm through fisheries-independent data, migration patterns, reproductive and feeding behaviours and habitat use. However, large-scale tagging experiments that would enable researchers to tackle group behaviour are difficult to set up. On the one hand, the impact of the actual tagging operation should be as minimal as possible to avoid any change in behaviour of the fish which could influence tag data analyses. On the other hand, large scale tagging experiments require handling a large number of animals in a relatively short period of time. In the present manuscript, a methodology for tagging several large ABFT with satellite tags was tested with ABFT caught from a cage of a Maltese farm. The total time of the operation, from the moment fish were caught by handline to release back to the sea lasted an average of 10 min for the 3 fish tagged. The handling of the fish on the deck lasted less than 2 min. This methodology proved successful at tagging several large (158–182 cm) fishes in a very short time, while ensuring the best conditions for the fish during tagging and subsequent release. This procedure requires substantial logistical preparation and an experienced crew team but, by reducing the time required for the operation, opens up the possibility of large scale tagging activities of large fish held in cages or caught by purse seiners.  
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  Langue Langue du Résumé Titre Original  
  Éditeur de collection Titre de collection Titre de collection Abrégé  
  Volume de collection Numéro de collection Edition  
  ISSN 0165-7836 ISBN Médium  
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  Numéro d'Appel MARBEC @ isabelle.vidal-ayouba @ collection 2487  
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