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Auteur Gimenez, O.; Buckland, S.T.; Morgan, B.J.T.; Bez, N.; Bertrand, S.; Choquet, R.; Dray, S.; Etienne, M.-P.; Fewster, R.; Gosselin, F.; Mérigot, B.; Monestiez, P.; Morales, J.M.; Mortier, F.; Munoz, F.; Ovaskainen, O.; Pavoine, S.; Pradel, R.; Schurr, F.M.; Thomas, L.; Thuiller, W.; Trenkel, V.; Valpine, P. de; Rexstad, E.
Titre Statistical ecology comes of age Type Article scientifique
Année 2014 Publication Revue Abrégée Biology Letters
Volume 10 Numéro 12 Pages 20140698
Mots-Clés
Résumé The desire to predict the consequences of global environmental change has been the driver towards more realistic models embracing the variability and uncertainties inherent in ecology. Statistical ecology has gelled over the past decade as a discipline that moves away from describing patterns towards modelling the ecological processes that generate these patterns. Following the fourth International Statistical Ecology Conference (1–4 July 2014) in Montpellier, France, we analyse current trends in statistical ecology. Important advances in the analysis of individual movement, and in the modelling of population dynamics and species distributions, are made possible by the increasing use of hierarchical and hidden process models. Exciting research perspectives include the development of methods to interpret citizen science data and of efficient, flexible computational algorithms for model fitting. Statistical ecology has come of age: it now provides a general and mathematically rigorous framework linking ecological theory and empirical data.
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Éditeur de collection Titre de collection Titre de collection Abrégé
Volume de collection Numéro de collection Edition
ISSN 1744-9561, 1744-957x ISBN Médium
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Auteur Zudaire, I.; Murua, H.; Grande, M.; Pernet, F.; Bodin, N.
Titre Accumulation and mobilization of lipids in relation to reproduction of yellowfin tuna (Thunnus albacares) in the Western Indian Ocean Type Article scientifique
Année 2014 Publication Revue Abrégée Fisheries Research
Volume Numéro Pages 50-59
Mots-Clés FADs; Fecundity; Income-capital breeder; Lipid class composition; Reproductive allocation strategy; Tropical tuna
Résumé Total lipid content and lipid class composition were analyzed in gonads, liver and white muscle of yellowfin tuna (Thunnus albacares) throughout ovary development to understand its reproductive allocation strategy and to assess the relation between female condition and reproduction. A total of 112 females were collected onboard purse-seiner in the Western Indian Ocean from January to March 2009, from June to July 2009, and from April to May 2010. Gonads were characterized by highly variable total lipid contents ranging from 5 to 27 μg mg−1 of wet weight (ww) with a predominance of neutral lipids, mainly triacylglycerols (TAG) and sterol- and wax-esters. The different lipid classes in gonads described an accumulative pattern through the maturity process from immature to hydration phase. Total lipid content in liver varied from 10 to 21 μg mg−1 ww, and serves as fuel for yellowfin tuna reproduction. TAG and phospholipid deposits became depleted as the ovary developed, suggesting a transfer of lipids directly from liver to the oocytes during vitellogenesis. In contrast, muscle total lipid content was low and constant throughout ovarian development (2.5–6 μg mg−1 ww). Hence, yellowfin tuna can be defined as an income-capital breeder species for which the cost of reproduction depends mainly on concurrent energy income from feeding and only little on stored lipids. Besides, no significant relationship between gonad lipid composition and fecundity was found in females able to spawn. Finally, the influence of yellowfin tuna aggregation behaviour on reproductive female condition has been investigated: gonad total lipid contents were higher in females caught in free-swimming schools than in females caught under fish aggregating devices (FADs). However, these results did not clarify whether the influence of FADs on associated yellowfin tuna affects their reproductive capacity.
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Langue Langue du Résumé Titre Original
Éditeur de collection Titre de collection Advances in Fisheries Research in Ibero-America Titre de collection Abrégé
Volume de collection 160 Numéro de collection Edition
ISSN 0165-7836 ISBN Médium
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Auteur Thiebault, A.; Mullers, R.; Pistorius, P.; Meza-Torres, M.A.; Dubroca, L.; Green, D.; Tremblay, Y.
Titre From colony to first patch: Processes of prey searching and social information in Cape Gannets Type Article scientifique
Année 2014 Publication Revue Abrégée The Auk
Volume 131 Numéro 4 Pages 595-609
Mots-Clés
Résumé ABSTRACT Seabirds forage in a highly dynamic environment and prey on fish schools that are patchily distributed. Colonially breeding seabirds regularly commute back and forth from their colony to foraging areas and need to acquire information on the location of food before and/or during each foraging trip. The use of conspecifics as cues to locate prey has long been debated, and although the hypothesis was backed up by modeling studies, observations have been contradictory. We deployed GPS devices coupled with micro video cameras on Cape Gannets to observe the social context of foraging seabirds and the influence of conspecifics on the movement of individuals. The Cape Gannets reached their first patch using a succession of flights interrupted by stops on the water, during which the birds were mainly preening. During flight, the birds reacted to conspecifics by changing direction, either flying in the opposite direction of conspecifics that were flying toward the colony or following conspecifics outward. The time to reach the first patch was significantly reduced (by half) when the birds reacted to conspecifics in these different ways, compared with the birds that did not react. The use of conspecifics flying toward the colony to find food is consistent with the hypothesis that colonies can act as a focal place for information transfer, with foragers updating their flying direction when they detect conspecifics flying toward the colony. The fine-scale reaction of seabirds toward each other at sea, and the associated improved foraging efficiency, as well as the division of trips into a succession of flights, constitute elements that indicate the existence and the use of a structured network among foraging Cape Gannets. , RÉSUMÉ Les oiseaux marins se nourrissent dans un environnement fortement dynamique et sur des proies agrégées en bancs. Les oiseaux coloniaux font régulièrement des aller-retours entre la colonie et les zones d'alimentation, et doivent alors acquérir de l'information sur la localisation de leurs proies avant et pendant chaque voyage en mer. L'utilisation de congénères comme source d'information pour localiser des proies a longtemps été débattue, et bien que cette hypothèse soit soutenue par des modèles théoriques, les observations empiriques restent contradictoires. Nous avons déployé des GPS et micro-caméras sur des individus de Morus capensis afin d'observer le contexte social de ces oiseaux au cours de leur recherche alimentaire et l'influence de congénères sur le déplacement des individus. Ceux-ci ont rejoint leur première zone d'alimentation par une succession de vols, interrompus par des arrêts sur l'eau durant lesquels ils faisaient principalement leur toilette. En vol, les oiseaux ont réagi à leurs congénères en modifiant leur direction, soit pour aller en direction opposée de congénères qui volaient vers la colonie, soit pour suivre des congénères au large. Le temps pour rejoindre la première zone d'alimentation était significativement réduit (de moitié) pour les oiseaux ayant réagi à leurs congénères de ces différentes manières, comparé aux oiseaux n'ayant pas réagi. L'utilisation de congénères volant vers la colonie pour trouver de la nourriture est en accord avec l'hypothèse de l'utilisation de la colonie comme point central pour l'échange d'information, à partir duquel les individus en recherche de nourriture pourraient ajuster leur direction de vol au fur et à mesure qu'ils rencontrent des congénères de retour vers la colonie. Les réactions à fine échelle entre oiseaux en mer, associées à l'amélioration de leur efficacité pour trouver de la nourriture, ainsi que le découpage du trajet en vols successifs, constituent des éléments en faveur de l'existence et de l'utilisation d'un réseau structuré de recherche alimentaire chez M. capensis. Mots-clés: biologging, caméra, centre d'information, GPS, oiseaux marins, prédateur à place centrale, recherche alimentaire en réseau, suivi
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Langue Langue du Résumé Titre Original
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Volume de collection Numéro de collection Edition
ISSN 0004-8038 ISBN Médium
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Auteur Thiebault, A.; Mullers, R.H.E.; Pistorius, P.A.; Tremblay, Y.
Titre Local enhancement in a seabird: reaction distances and foraging consequence of predator aggregations Type Article scientifique
Année 2014 Publication Revue Abrégée Behavioral Ecology
Volume 25 Numéro 6 Pages 1302-1310
Mots-Clés camera; foraging cues; gannet; Gps; group hunting; network foraging; prey detection; social information.
Résumé Seabirds foraging on pelagic fish develop behavioral strategies specifically adapted to locate inconspicuous prey that are aggregated in spatially dynamic patches. In the marine environment, they may use various mechanisms to detect cues of prey availability. The aggregation of predators at a patch of food is a particularly obvious cue to locate prey, a mechanism known as local enhancement. Pioneering studies described the formation of foraging groups at sea, showing that seabirds are attracted to feeding conspecifics. Improved foraging success due to local enhancement has been suggested from modeling studies, but no direct validation of these results exists. We deployed video cameras concomitantly with GPS loggers on Cape gannets to study the behavioral responses of equipped birds to the aggregation of predators at food patches. We showed that the reaction distances of equipped birds increased with the size of an aggregation, demonstrating that predator aggregations enhance food detectability for foragers. For small aggregations (<50 gannets), reaction distances were mostly less than 10 km, and they increased up to almost 40 km for larger aggregations (100–150 gannets). In addition, we showed that the number and frequency of dives increased with the number of conspecifics aggregated, up to a threshold. The predator aggregations on a patch of food could, therefore, not only inform about the presence of prey but also entail information about foraging conditions. From direct observations on the various components involved, our study provides justification of the use and advantages of local enhancement in foraging seabirds.
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Volume de collection Numéro de collection Edition
ISSN 1045-2249, 1465-7279 ISBN Médium
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Auteur Shannon, L.; Coll, M.; Bundy, A.; Gascuel, D.; Heymans, J.J.; Kleisner, K.; Lynam, C.P.; Piroddi, C.; Tam, J.; TraversTrolet, M.; Shin, Y.
Titre Trophic level-based indicators to track fishing impacts across marine ecosystems Type Article scientifique
Année 2014 Publication Revue Abrégée Mar Ecol Prog Ser
Volume 512 Numéro Pages 115-140
Mots-Clés
Résumé ABSTRACT: Trophic level (TL)-based indicators have been widely used to examine fishing impacts in aquatic ecosystems and the induced biodiversity changes. However, much debate has ensued regarding discrepancies and challenges arising from the use of landings data from commercial fisheries to calculate TL indicators. Subsequent studies have started to examine survey-based and model-based indicators. In this paper, we undertake an extensive evaluation of a variety of TL indicators across 9 well-studied marine ecosystems by making use of model- as well as survey- and catch-based TL indicators. Using detailed regional information and data on fishing history, fishing intensity, and environmental conditions, we evaluate how well TL indicators are capturing fishing effects at the community level of marine ecosystems. Our results highlight that the differences observed between TL indicator values and trends is dependent on the data source and the TL cut-off point used in the calculations and is not attributable to an intrinsic problem with TL-based indicators. All 3 data sources provide useful information about the structural changes in the ecosystem as a result of fishing, but our results indicate that only model-based indicators represent fishing impacts at the whole ecosystem level.
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Numéro d'Appel MARBEC @ isabelle.vidal-ayouba @ collection (down) 1206
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