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Auteur (up) Jimenez, H.; Dumas, P.; Mouillot, D.; Bigot, L.; Ferraris, J.
Titre Harvesting effects on functional structure and composition of tropical invertebrate assemblages Type Article scientifique
Année 2016 Publication Revue Abrégée ICES J. Mar. Sci.
Volume 73 Numéro 2 Pages 420-428
Mots-Clés Bta; marine protected areas; shellfishing; species composition; tropical benthos
Résumé Anthropogenic disturbances affect ecosystem structure and functioning. The quantification of their impacts on highly diverse and structurally complex ecosystems, such as coral reefs, is challenging. These communities are facing rising fishing pressure, particularly on Pacific Islands such as New Caledonia. The main objective was to quantify harvesting effects on invertebrate assemblages across two contrasting habitats (soft- and hard-bottom), by comparing communities in marine protected areas (MPAs) with non-MPAs using 10 biological and ecological traits. Patterns of trait composition were compared with those of species composition by non-metric multidimensional scaling and permutational analysis of variance analyses. Traits most responsible for differences between MPAs and non-MPAs were determined using SIMPER analysis, and predictions on shellfishing effects were discussed. A total of 248 species were recorded in hard-bottom communities, mainly characterized by mobile epifauna living on corals, crawling, and possessing a shell (molluscs) or a cuticle (crabs and echinoderms). Soft-bottom habitats contained 166 species, dominated by burrowing and sedentary species, especially shelled (largely bivalves) and worm-like organisms. Clear differences in species and trait composition between MPA and non-MPAs were highlighted in both habitats. Harvesting activities have community-wide effects that change the functional composition of invertebrate assemblages, in particular in terms of living habits and mobility. The observed shifts in benthic communities can affect the functioning of tropical coastal ecosystems and need to be included in small-scale fisheries management in poorly known tropical environments.
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Volume de collection Numéro de collection Edition
ISSN 1054-3139, 1095-9289 ISBN Médium
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Numéro d'Appel MARBEC @ alain.herve @ collection 1535
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Auteur (up) Joo, R.; Bertrand, S.; Chaigneau, A.; Niquen, M.
Titre Optimization of an artificial neural network for identifying fishing set positions from VMS data : an example from the Peruvian anchovy purse seine fishery Type Article scientifique
Année 2011 Publication Revue Abrégée Ecological Modelling
Volume 222 Numéro Pages 1048-1059
Mots-Clés analysis; anchovy; Artificial; fishery; Fishing; locations; Monitoring; networks; neural; purse; seine; Sensitivity; set; System; Vessel
Résumé The spatial behavior of numerous fishing fleets is nowadays well documented thanks to satellite Vessel Monitoring Systems (VMS). Vessel positions are recorded on a frequent and regular basis which opens promising perspectives for improving fishing effort estimation and management. However, no specific information is provided on whether the vessel is fishing or not. To answer that question, existing works on VMS data usually apply simple criteria (e.g. threshold on speed). Those simple criteria generally focus in detecting true positives (a true fishing set detected as a fishing set); conversely, estimation errors are given no attention. For our case study, the Peruvian anchovy fishery, those criteria overestimate the total number of fishing sets by 182%. To overcome this problem an artificial neural network (ANN) approach is presented here. In order to set both the optimal parameterization and use “rules” for this ANN, we perform an extensive sensitivity analysis on the optimization of (1) the internal structure and training algorithm of the ANN and (2) the “rules” used for choosing both the relative size and the composition of the databases (DBs) used for training and inferring with the ANN. The “optimized” ANN greatly improves the estimates of the number and location of fishing events. For our case study, ANN reduces the total estimation error on the number of fishing sets to 1% (in average) and obtains 76% of true positives. This spatially explicit information on effort, provided with error estimation, should greatly reduce misleading interpretations of catch per unit effort and thus significantly improve the adaptive management of fisheries. While fitted on Peruvian anchovy fishery data, this type of neural network approach has wider potential and could be implemented in any fishery relying on both VMS and at-sea observer data. In order to increase the accuracy of the ANN results, we also suggest some criteria for improving sampling design by at-sea observers and VMS data.
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Volume de collection Numéro de collection Edition
ISSN 0304-3800 ISBN Médium
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Numéro d'Appel LL @ pixluser @ collection 147
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Auteur (up) Jouffre, D.; Borges, M. de F.; Bundy, A.; Coll, M.; Diallo, I.; Fulton, E.A.; Guitton, J.; Labrosse, P.; Abdellahi, K.O.M.; Masumbuko, B.; Thiao, D.
Titre Estimating EAF indicators from scientific trawl surveys: theoretical and practical concerns Type Article scientifique
Année 2010 Publication Revue Abrégée Ices Journal of Marine Science
Volume 67 Numéro 4 Pages 796-806
Mots-Clés Eaf; ecological indicators; ecosystem effect of fishing; historical data; trawling surveys
Résumé Under the context of an ecosystem approach to fisheries (EAF), there is keen interest in providing insights into the evolution of exploited ecosystems using simple ecosystem indicators. Many nations have long-term scientific research surveys, originally driven by conventional approaches in fisheries assessment and management. The aim of this study is to address the practical concerns linked to current objectives of monitoring simple EAF indicators, using data from surveys that were not historically designed for the purpose. Based on the results of an expert survey designed to collect expert knowledge on research surveys from scientists working on different ecosystems worldwide, a list of challenges faced during indicator estimation is highlighted, along with associated concerns and constraints. The work provides additional information useful in the interpretation of the results obtained on the state and trends of ecosystems using EAF indicators by the IndiSeas WG. Further, the related discussion provides potential pathways that could be useful for future research and development aiming to improve the ecosystem indicator approach in the operational context of EAF. The question of the utility for EAF of using historical dataseries of scientific trawl series is also discussed. Such long-term series are concluded to be useful, that they are even inescapable (since the past cannot be resamplied), and that EAF therefore brings a supplementary reason for continuing such monitoring and to incorporate new insights in how research surveys may be conducted.
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Editeur Lieu de Publication Éditeur
Langue Langue du Résumé Titre Original
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Volume de collection Numéro de collection Edition
ISSN 1054-3139 ISBN Médium
Région Expédition Conférence
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Numéro d'Appel LL @ pixluser @ collection 79
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Auteur (up) KLEISNER, K.M.; COLL, M.; LYNAM, C.P.; BUNDY, A.; SHANNON, L.; SHIN, Y.-J.; BOLDT, J.L.; BORGES, M.F.; DIALLO, I.; FOX, clive; GASCUEL, D.; HEYMANS, J.J.; JUAN JORDA, M.J.; JOUFFRE, D.; LARGE, S.I.; MARSHALL, K.N.; OJAVEER, H.; PIRODDI, C.; TAM, J.; TORRES, M.A.; TRAVERS-TROLET, M.; TSAGARAKIS, K.; VAN DER MEEREN, G.I.; ZADOR, S.
Titre Evaluating changes in marine communities that provide ecosystem services through comparative assessments of community indicators Type Article scientifique
Année 2015 Publication Ecosystem Services Revue Abrégée
Volume 16 Numéro Pages 413-429
Mots-Clés Ecological indicator; Comparative approach; Community metric; IndiSeas; Fishing impacts
Résumé Fisheries provide critical provisioning services, especially given increasing human population. Understanding where marine communities are declining provides an indication of ecosystems of concern and highlights potential conflicts between seafood provisioning from wild fisheries and other ecosystem services. Here we use the nonparametric statistic, Kendall׳s tau, to assess trends in biomass of exploited marine species across a range of ecosystems. The proportion of ‘Non-Declining Exploited Species’ (NDES) is compared among ecosystems and to three community-level indicators that provide a gauge of the ability of a marine ecosystem to function both in provisioning and as a regulating service: survey-based mean trophic level, proportion of predatory fish, and mean life span. In some ecosystems, NDES corresponds to states and temporal trajectories of the community indicators, indicating deteriorating conditions in both the exploited community and in the overall community. However differences illustrate the necessity of using multiple ecological indicators to reflect the state of the ecosystem. For each ecosystem, we discuss patterns in NDES with respect to the community-level indicators and present results in the context of ecosystem-specific drivers. We conclude that using NDES requires context-specific supporting information in order to provide guidance within a management framework.
Adresse Alaska Fisheries Science Center, National Marine Fisheries Service, National Oceanic and Atmospheric Administration, 7600 Sand Point Way NE, Seattle, WA 98115, USA
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Editeur Elsevier BV Lieu de Publication Éditeur
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Volume de collection Numéro de collection Edition
ISSN 2212-0416 ISBN Médium
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Numéro d'Appel MARBEC @ isabelle.vidal-ayouba @ 36555 collection 1233
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Auteur (up) LAGABRIELLE, E.; CROCHELET, E.; ANDRELLO, M.; SCHILL, S.R.; ARNAUD-HAOND, S.; ALLONCLE, N.; PONGE, B.
Titre Connecting MPAs – eight challenges for science and management Type Article scientifique
Année 2014 Publication Revue Abrégée Aquatic Conservation-marine And Freshwater Ecosystems
Volume 24 Numéro Pages 94-110
Mots-Clés coastal; conservation evaluation; Fishing; Marine Protected Areas; ocean; spatial modelling
Résumé Connectivity is a crucial process underpinning the persistence, recovery, and productivity of marine ecosystems. The Convention on Biological Diversity, through the Aichi Target 11, has set the ambitious objective of implementing a ‘well connected system of protected areas’ by 2020. This paper identifies eight challenges toward the integration of connectivity into MPA network management and planning. A summary table lists the main recommendations in terms of method, tool, advice, or action to address each of these challenges. Authors belong to a science–management continuum including researchers, international NGO officers, and national MPA agency members. Three knowledge challenges are addressed: selecting and integrating connectivity measurement metrics; assessing the accuracy and uncertainty of connectivity measurements; and communicating and visualizing connectivity measurements. Three management challenges are described: integrating connectivity into the planning and management of MPA networks; setting quantitative connectivity targets; and implementing connectivity-based management across scales and marine jurisdictions. Finally, two paths toward a better integration of connectivity science with MPA management are proposed: setting management-driven priorities for connectivity research, bridging connectivity science, and MPA network management. There is no single method to integrate connectivity into marine spatial planning. Rather, an array of methods can be assembled according to the MPA network objectives, budget, available skills, data, and timeframe. Overall, setting up ‘boundary organizations’ should be promoted to organize complex cross-disciplinary, cross-sectoral and cross-jurisdiction interactions that are needed between scientists, managers, stakeholders and decision-makers to make informed decision regarding connectivity-based MPA planning and management.
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Editeur Lieu de Publication Éditeur
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Volume de collection Numéro de collection Edition
ISSN 1052-7613 ISBN Médium
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Notes Approuvé pas de
Numéro d'Appel MARBEC @ isabelle.vidal-ayouba @ collection 1133
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