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Auteur |
Mariani, P.; Křivan, V.; MacKenzie, B.R.; Mullon, C. |
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Titre |
The migration game in habitat network: the case of tuna |
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Article scientifique |
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Année |
2016 |
Publication |
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Revue Abrégée |
Theor Ecol |
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Volume |
9 |
Numéro |
2 |
Pages |
219-232 |
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Mots-Clés |
Bluefin tuna; Game theory; Habitat selection; Ideal free distribution; Plant Sciences; Structured population; Theoretical Ecology/Statistics; Zoology |
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Résumé  |
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 |
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ISSN |
1874-1738, 1874-1746 |
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pas de |
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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. |
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Titre |
Ecological bridges and barriers in pelagic ecosystems |
Type |
Article scientifique |
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Année |
2017 |
Publication |
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Revue Abrégée |
Deep-Sea Res. Part II-Top. Stud. Oceanogr. |
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Volume |
140 |
Numéro |
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Pages |
182-192 |
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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 |
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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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English |
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ISSN |
0967-0645 |
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pas de |
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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. |
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Titre |
Impacts of climate variability on the tuna economy of Seychelles |
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Article scientifique |
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Année |
2010 |
Publication |
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Revue Abrégée |
Climate Research |
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Volume |
43 |
Numéro |
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Pages |
149-162 |
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Mots-Clés |
climate; economy; Enso; fisheries; Seychelles; tuna; variability |
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Résumé |
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 |
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Numéro d'Appel |
LL @ pixluser @ |
collection |
101 |
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Auteur |
Eduardo Nole, L.; Lucena-Fredou, F.; Mincarone, M.M.; Soares, A.; Le Loc'h, F.; Fredou, T.; Menard, F.; Bertrand, A. |
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Titre |
Trophic ecology, habitat, and migratory behaviour of the viperfish Chauliodus sloani reveal a key mesopelagic player |
Type |
Article scientifique |
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Année |
2020 |
Publication |
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Revue Abrégée |
Sci Rep |
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Volume |
10 |
Numéro |
1 |
Pages |
20996 |
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Mots-Clés |
atlantic bluefin tuna; carbon transport; feeding ecology; fish assemblage; northeast atlantic; pisces stomiidae; southern tasmania; species composition; thunnus-thynnus; vertical-distribution |
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Résumé |
Mesopelagic fishes are numerically the most important vertebrate group of all world's oceans. While these species are increasingly threatened by anthropogenic activities, basic biological knowledge is still lacking. For instance, major uncertainties remain on the behaviour, ecology, and thus functional roles of mesopelagic micronektivores, particularly regarding their interactions with physicochemical features. Here, we examine the trophic ecology, habitat, and migratory behaviour of the viperfish (Chauliodus sloani)-a poorly known and abundant deep-sea species-to further understand the ecology and thus functional role of mesopelagic micronektivores. Moreover, we explore how physical drivers may affect these features and how these relationships are likely to change over large oceanic areas. The viperfish heavily preys on epipelagic migrant species, especially myctophids, and presents spatial and trophic ontogenetic shifts. Temperature restricts its vertical distribution. Therefore, its trophodynamics, migratory behaviour, and functional roles are expected to be modulated by the latitudinal change in temperature. For instance, in most tropical regions the viperfish stay full-time feeding, excreting, and serving as prey (e.g. for bathypelagic predators) at deep layers. On the contrary, in temperate regions, the viperfish ascend to superficial waters where they trophically interact with epipelagic predators and may release carbon where its remineralization is the greatest. |
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Auteur institutionnel |
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Lieu de Publication |
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Éditeur |
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Langue |
English |
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Titre Original |
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Titre de collection Abrégé |
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ISSN |
2045-2322 |
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Notes |
WOS:000600427300001 |
Approuvé |
pas de |
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Numéro d'Appel |
MARBEC @ isabelle.vidal-ayouba @ |
collection |
2933 |
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Auteur |
Guyader, O.; Robert, B.; Lionel, R. |
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Titre |
Assessing the number of moored fishing aggregating devices through aerial surveys: A case study from Guadeloupe |
Type |
Article scientifique |
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Année |
2017 |
Publication |
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Revue Abrégée |
Fish Res. |
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Volume |
185 |
Numéro |
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Pages |
73-82 |
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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 |
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Résumé |
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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Auteur institutionnel |
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Langue |
English |
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Titre Original |
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Titre de collection Abrégé |
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ISSN |
0165-7836 |
ISBN |
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pas de |
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Numéro d'Appel |
MARBEC @ alain.herve @ |
collection |
1696 |
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