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Auteur Walker, T.R.; Grant, J.; Weise, A.M.; McKindsey, C.W.; Callier, M.D.; Richard, M.
Titre Influence of suspended mussel lines on sediment erosion and resuspension in Lagune de la Grande Entree, Iles-de-la-Madeleine, Quebec, Canada Type Article scientifique
Année 2014 Publication Revue Abrégée Aquaculture
Volume 433 Numéro Pages 450-457
Mots-Clés Aquaculture; Biodeposits; biogeochemical fluxes; culture; dynamics; intertidal cohesive sediments; lagoon; Mytilus; Mytilus edulis; Particle; rates; Resuspension; Sediment erosion; Shear velocity; size; stability
Résumé (up) Downward fluxes of organically rich biodeposits under suspended mussel lines can cause benthic impacts such as changes in benthic community structure or microbial mat production. Quantifying sediment erosion in these coastal ecosystems is important for understanding how fluxes of organic matter and mussel biodeposits contribute to benthic pelagic coupling. Critical shear velocity (u(crit)*(t)), erosion rates and particle size distributions of resuspended sediment were measured at four stations distributed along a transect perpendicular to a mussel farm in Lagune de la Grande Entree, Iles-de-la-Madeleine (Quebec, Canada). Stations were selected underneath the outer-most mussel line (0 m) and at distances of 15,30 m and at a reference station (500 m) further along the transect. Shear velocity was measured using a calibrated portable Particle Erosion Simulator, also referred to as the BEAST (Benthic Environmental Assessment Sediment Tool). Undisturbed sediment cores obtained by divers were exposed to shear stress to compare differences between stations. Erosion sequences indicated no significant differences in u(crit)* between stations, but there were significant differences in erosion rates beneath mussel lines compared to other stations. Erosion rates were the highest in cores from beneath mussel lines, but paradoxically had the lowest u(crit)* Mean erosion rates at u*crit varied between 25 and 47 g m(-2) min(-1) and critical erosion thresholds varied between 1.58 and 1.73 cm s(-1), which compare with intensive mussel culture sites elsewhere in eastern Canada. Significant differences existed in biotic and abiotic properties of sediments which could explain variation in maximum erosion rates within and between stations. Particle sizes measured by videography of resuspended sediment at different shear velocities ranged from 02 to 3.0 mm. Quantifying sediment erosion from intact marine sediments helps to improve our mechanistic understanding of these processes, and the BEAST further contributes to predictive capability in benthic pelagic coupling modeling. (C) 2014 Elsevier B.V. All rights reserved.
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Langue English Langue du Résumé Titre Original
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ISSN 0044-8486 ISBN Médium
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Notes <p>ISI Document Delivery No.: AQ1GH<br/>Times Cited: 0<br/>Cited Reference Count: 39<br/>Walker, Tony R. Grant, Jon Weise, Andrea M. McKindsey, Christopher W. Callier, Myriam D. Richard, Marion<br/>Natural Sciences and Engineering Research Council of Canada (NSERC); Aquaculture Collaborative Research and Development Program (ACRDP); Societe de Development de l'Industrie Maricole (SODIM); Fisheries and Oceans Canada<br/>We thank MAPAQ and B. Hargrave for the collaboration and C. Eloquin and associates for the permission to use their site. Funding was provided by the Aquaculture Collaborative Research and Development Program (ACRDP), the Societe de Development de l'Industrie Maricole (SODIM) and the Fisheries and Oceans Canada. We thank B. Schofield and M. Merrimen for the fabrication of the BEAST which formed part of the equipment necessary for the Canadian Arctic Shelves Exchange Study (CASES), a Research Network funded by the Natural Sciences and Engineering Research Council of Canada (NSERC).<br/>Elsevier science bv<br/>Amsterdam</p> Approuvé pas de
Numéro d'Appel MARBEC @ alain.herve @ collection 1180
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Auteur Rishworth, G.M.; Tremblay, Y.; Green, D.B.; Connan, M.; Pistorius, P.A.
Titre Drivers of Time-Activity Budget Variability during Breeding in a Pelagic Seabird Type Article scientifique
Année 2014 Publication Revue Abrégée PLoS ONE
Volume 9 Numéro 12 Pages
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Résumé (up) During breeding, animal behaviour is particularly sensitive to environmental and food resource availability. Additionally, factors such as sex, body condition, and offspring developmental stage can influence behaviour. Amongst seabirds, behaviour is generally predictably affected by local foraging conditions and has therefore been suggested as a potentially useful proxy to indicate prey state. However, besides prey availability and distribution, a range of other variables also influence seabird behavior, and these need to be accounted for to increase the signal-to-noise ratio when assessing specific characteristics of the environment based on behavioural attributes. The aim of this study was to use continuous, fine-scale time-activity budget data from a pelagic seabird (Cape gannet, Morus capensis) to determine the influence of intrinsic (sex and body condition) and extrinsic (offspring and time) variables on parent behaviour during breeding. Foraging trip duration and chick provisioning rates were clearly sex-specific and associated with chick developmental stage. Females made fewer, longer foraging trips and spent less time at the nest during chick provisioning. These sex-specific differences became increasingly apparent with chick development. Additionally, parents in better body condition spent longer periods at their nests and those which returned later in the day had longer overall nest attendance bouts. Using recent technological advances, this study provides new insights into the foraging behaviour of breeding seabirds, particularly during the post-guarding phase. The biparental strategy of chick provisioning revealed in this study appears to be an example where the costs of egg development to the female are balanced by paternal-dominated chick provisioning particularly as the chick nears fledging.
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Numéro d'Appel MARBEC @ isabelle.vidal-ayouba @ collection 1202
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Auteur Boyd, C.; Punt, A.E.; Weimerskirch, H.; Bertrand, S.
Titre Movement models provide insights into variation in the foraging effort of central place foragers Type Article scientifique
Année 2014 Publication Revue Abrégée Ecological Modelling
Volume 286 Numéro Pages 13-25
Mots-Clés Animal movement; Foraging ecology; Hidden Markov model; Provisioning theory; Seabirds; Sula variegata
Résumé (up) Ecology and conservation depend on an understanding of how animals adjust their behaviour patterns in response to changes in their environment. Central place foragers (CPFs) are well-suited for developing ecological models of adaptive processes because their objective functions and operational constraints can be reasonably inferred. Central place foraging and provisioning theory provide the theoretical framework for this analysis. Analysis of CPF time allocation and energy budgets can provide insights into their strategies for responding to environmental variation. However, until recently, suitable high-resolution data on the behaviour of seabirds and other CPFs at sea have not been available. Previous studies of breeding seabirds have investigated variation in foraging trip duration and colony attendance, but few studies have analyzed variation in time allocation within foraging trips. Here, we develop a conceptual energy-based model for analysing variation in the time allocation of CPFs during foraging trips, and apply it to the movement patterns of Peruvian boobies (Sula variegata). Foraging trips of Peruvian boobies, recorded using high-resolution global positioning systems (GPS), were first partitioned into movement modes consistent with travel and foraging behaviours using a hidden Markov model (HMM) adapted to account for gaps in the GPS tracks associated with diving behaviour. Analysis of the HMM results based on the conceptual model indicated that differences in foraging effort between two treatments were best explained by a combination of differences in travel time and in time spent searching for prey. The conceptual model provides the basis for an integrated approach to analysis of variation in foraging strategies in which identification of various behaviours is coupled with assessments of time and energy budgets. This integrated approach can contribute to greater understanding of the processes determining foraging strategies and the limits to these strategies in the context of competition for resources and global climate change.
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ISSN 0304-3800 ISBN Médium
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Numéro d'Appel LL @ pixluser @ collection 355
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Auteur Kaplan, D.; Chassot, E.; Amande, J.M.; Dueri, S.; Demarcq, H.; Dagorn, L.; Fonteneau, A.
Titre Spatial management of Indian Ocean tropical tuna fisheries: potential and perspectives Type Article scientifique
Année 2014 Publication Revue Abrégée Ices Journal of Marine Science
Volume 71 Numéro 7 Pages 1728-1749
Mots-Clés Bycatch; conservation; Indian Ocean; Marine protected areas (MPAs); pelagic; spatial management of fisheries; tropical tuna fisheries
Résumé (up) Effective use of spatial management in the pelagic realm presents special challenges due to high fish and fisher mobility, limited knowledge and significant governance challenges. The tropical Indian Ocean provides an ideal case study for testing our ability to apply existing data sources to assessing impacts of spatial management on tuna fisheries because of several recent controversial spatial closures. We review the scientific underpinnings of pelagic MPA effects, spatio-temporal patterns of Indian Ocean tuna catch, by catch and fish movements, and the consequences of these for the efficacy of spatial management for Indian Ocean tropical tuna fisheries. The tropical Indian Ocean is characterized by strong environmental fluctuations, regular seasonal variability in catch, large observed tuna displacement distances, relatively uniform catch-per-unit-effort and bycatch rates over space, and high fisher mobility, all of which suggest significant variability and movement in tropical tuna fisheries that are simply not well adapted to static spatial closures. One possible exception to this overall conclusion would be a large time/area closure east of Somalia. If closed for a significant fraction of the year it could reduce purse-seine bycatch and juvenile tuna catch. Dynamic closures following fish migratory patterns are possible, but more focused information on fish movements will be needed for effective implementation. Fortunately, several recent improvements in conventional fishery management and reporting will likely enhance our ability to evaluate spatial and non-spatial management options in the near future, particularly as pertaining to bycatch species.
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ISSN 1054-3139 ISBN Médium
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Numéro d'Appel MARBEC @ isabelle.vidal-ayouba @ collection 1199
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Auteur ROUYER, T.; FROMENTIN, J.-M.; HIDALGO, M.; STENSETH, N.C.
Titre Combined effects of exploitation and temperature on fish stocks in the Northeast Atlantic Type Article scientifique
Année 2014 Publication Ices Journal Of Marine Science Revue Abrégée
Volume 71 Numéro 7 Pages 1554-1562
Mots-Clés combined climate/exploitation effect; exploitation; fish stocks; Northeast Atlantic; response to climate; time-series
Résumé (up) Fish stock fluctuations are affected by two potentially confounding forces: the removal of individuals by fisheries and climatic variations affecting the productivity of fish populations. Disentangling the relative importance of these forces has thus been a question of primary importance for fisheries management and conservation. Through the analysis of long-term time-series for 27 fish stocks from the Northeast Atlantic, the present study shows that the sign and intensity of the effect of temperature on biomass are dependent on the geographical location: the stocks located at the southernmost and northernmost latitudes of our study displayed stronger associations with temperature than the stocks located in the middle range of latitudes. As a consequence, the investigation of the combined effects of exploitation and the environment revealed that the stocks at the northern/southern boundaries of the spatial extent of the species were more prone to combined effects. The interplay between geographic location, climate and exploitation thus plays a significant role in fish stock productivity, which is generally ignored during assessment, thus affecting management procedures.
Adresse Inst Marine Res, Dept Coastal Zone Studies, Flodevigen Res Stn, N-4817 His, Norway.
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Editeur Oxford Univ Press Lieu de Publication Éditeur
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Numéro d'Appel MARBEC @ isabelle.vidal-ayouba @ 34107 collection 983
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