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Auteur Braham, C.B.; Freon, P.; Laurec, A.; Demarcq, H.; Bez, N.
Titre New insights in the spatial dynamics of sardinella stocks off Mauritania (North-West Africa) based on logbook data analysis Type Article scientifique
Année 2014 Publication Revue Abrégée Fisheries Research
Volume 154 Numéro (up) Pages 195-204
Mots-Clés
Résumé Sardinella spp. are the main species fished in Mauritanian waters. Logbook data (1991&8211;2009) were used to standardise CPUE. This clearly revealed that the abundance of sardinella peaked in the warm season (July&8211;September) which is the main, if not the only significant spawning season for round sardinella.

This study does not directly confirm or falsify the common belief that the adults migrate from the Senegalese EEZ up to north of the 21° N latitude, but it presents a variety of new hypotheses. If a single transboundary stock exists, part of its individuals, or a sub-stock, is probably more sedentary and remains in the permanent upwelling area located in northern Mauritania and southern Morocco.

Between years, changes in abundance index are dominated by a decrease from 1996 to 2006, depending on the months taken into account, and especially whether or not the warm (spawning) season is considered. For a given month, the spatial distribution of sardinella shows limited differences between years. In the southernmost latitudes of the Mauritanian EEZ the seasonal pattern, which is dominated by high catch rates during the warm season, is much stronger after the year 2001, and then tended to increase year after year.

Changes in species distribution and abundance during the twenty-year study period are difficult to relate to environmental dynamics. However, an inversion of the upwelling trend was observed in 2001, matching a change in the seasonality of sardinella catches, although the causality between the two phenomena could not be established. The increase in the abundance index of sardinella in the last five years, particularly during most of the core fishing season (July&8211;September) might be due to favourable oceanographic conditions (higher upwelling index) and/or changes in the fishing strategies or efficiency. Before annual indices of abundance can be used in the future, it will be necessary to better understand possible changes in catchability during the warm/spawning season.
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Langue eng 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 1147
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Auteur Coll, M.; Carreras, M.; Cornax, M.J.; Massuti, E.; Morote, E.; Pastor, X.; Quetglas, A.; SàeZ, R.; Sobrino, I.; Torres, M.A.; Tudela, S.; Harper, S.; Zeller, H.; Pauly, D.
Titre Closer to reality : reconstructing total removals in mixed fisheries from Southern Europe Type Article scientifique
Année 2014 Publication Revue Abrégée Fisheries Research
Volume 154 Numéro (up) Pages 179-194
Mots-Clés
Résumé Underestimation of catches is especially important in countries where fishing fleets are highly diversified, the enforcement of fishery management is low, data availability is poor, and there is high demand for fish products in local markets. This is the case for southern European and Mediterranean regions. Adapting a catch-reconstruction approach, we estimated the total removals of marine resources by Spain for the Spanish Mediterranean Sea and Gulf of Cadiz regions from 1950 to 2010. We collected available information from scientific publications, the grey literature and secondary sources of information to complement officially reported catch data. We assessed missing catch sectors as time-point estimates, used as anchor points of reliable data upon which we then estimated total catch using interpolation to fill in the periods for which quantitative data were missing. Unreported removals and discards represented important portions of total removals in the study area. They accounted for, on average, 43% of total removals between 1950s and 2010, and were composed of black market sales, subsistence fishing, artisanal fishing, recreational fishing and illegal catch, in addition to discarding. By the late 2000s, recreational fishing was the most important sector for unreported landings (similar to 36%), followed by black market sales (similar to 32%), subsistence fishing (similar to 17%), unreported artisanal fishing (similar to 12%) and illegal catch (similar to 2%). The overall catch trend differed from the official trend highlighting that the depletion of marine resources in the region started earlier than previously observed. The catch composition changed with time, with a higher diversification of species in fish markets with time. These results indicate an earlier trend towards expansion of fisheries and depletion of marine resources.
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Langue eng 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 LL @ pixluser @ collection 381
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Auteur Levin, N.; Coll, M.; Fraschetti, S.; Gal, G.; Giakoumi, S.; Gke, C.; Heymans, J.J.; Katsanevakis, S.; Mazor, T.; ztrk, B.; Rilov, G.; Gajewski, J.; Steenbeek, J.; Kark, S.
Titre REVIEW Biodiversity data requirements for systematic conservation planning in the Mediterranean Sea Type Article scientifique
Année 2014 Publication Revue Abrégée Mar Ecol Prog Ser
Volume 508 Numéro (up) Pages 261-281
Mots-Clés
Résumé ABSTRACT: The Mediterranean Sea’s biodiversity and ecosystems face many threats due to anthropogenic pressures. Some of these include human population growth, coastal urbanization, accelerated human activities, and climate change. To enhance the formation of a science-based system of marine protected areas in the Mediterranean Sea, data on the spatial distribution of ecological features (abiotic variables, species, communities, habitats, and ecosystems) is required to inform conservation scientists and planners. However, the spatial data required is often lacking. In this review, we aimed to address the status of our knowledge for 3 major types of spatial information: bathymetry, classification of marine habitats, and species distributions. To exemplify the data gaps and approaches to bridge them, we examined case studies that systematically prioritize conservation in the Mediterranean Sea. We found that at present the data required for conservation planning is generally more readily available and of better quality for the European countries located in the Western Mediterranean Sea. Additionally, the Mediterranean Sea is lagging behind other marine regions where rigorous criteria for conservation planning has been applied in the past 20 yr. Therefore, we call upon scientists, governments, and international governmental and non-governmental organizations to harmonize current approaches in marine mapping and to develop a framework that is applicable throughout the Mediterranean region. Such coordination between stakeholders is urgently needed before more countries undertake further extensive habitat mapping, so that future conservation planning can use integrated spatial datasets.
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Numéro d'Appel LL @ pixluser @ collection 383
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Auteur Langlois, J.; Freon, P.; Delgenes, J.P.; Steyer, J.P.; Helias, A.
Titre New methods for impact assessment of biotic-resource depletion in life cycle assessment of fisheries : theory and application Type Article scientifique
Année 2014 Publication Revue Abrégée Journal of Cleaner Production
Volume 73 Numéro (up) Pages 63-71
Mots-Clés Biotic resource depletion; fisheries; Maximum; Net primary production; sustainable yield
Résumé It is difficult to address all of the direct environmental impacts of fisheries using conventional methods of Life Cycle Assessment (LCA). A methodological framework was developed that calculates regionalised characterisation factors for biomass uptake by fishing activities to assess impacts of biotic-resource depletion at both species and ecosystem levels. These two levels were studied to include effects of catch on the collapse of a particular stock of a given species and on total biomass availability in oceans. Characterisation factors were calculated for 127 fish species and 88 marine provinces. The compatibility of this method with other frameworks is discussed, as well as the methodological limitations. The method was applied to two contrasting examples from fisheries (Northern Atlantic albacore tuna and Northern Argentine anchovy). The impacts of one tonne of tuna on biotic natural resources were 4 and 14 times as high as those of anchovy at the ecosystem and species levels, respectively. The application demonstrates that the method is relevant, as it addresses a topic of global interest and fills a gap in LCA impact assessment to contrast impacts of removals of different fish species in terms of biotic natural resource depletion.
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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 0959-6526 ISBN Médium
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Numéro d'Appel MARBEC @ isabelle.vidal-ayouba @ collection 1152
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Auteur Ternon, J.F.; Roberts, M.J.; Morris, T.; Hancke, L.; Backeberg, B.
Titre In situ measured current structures of the eddy field in the Mozambique Channel Type Article scientifique
Année 2014 Publication Revue Abrégée Deep Sea Research Part II: Topical Studies in Oceanography
Volume Numéro (up) Pages 10-26
Mots-Clés Geostrophic currents; Mesoscale eddies; Mozambique Channel; S-ADCP measurements; Wind driven circulation
Résumé Circulation and the related biological production have been studied during five cruises conducted in the Mozambique Channel (MZC) between 2005 and 2010. The circulation in the MZC is known to be highly turbulent, favouring enhanced primary production as a result of mesoscale eddy dynamics, and connectivity throughout the Channel due to the variable currents associated with migrating eddies. This paper presents the results of in situ measurements that characterize the horizontal and vertical currents in the surface and subsurface layers (0–500 m). The in situ data were analysed together with the geostrophic eddy field observed from satellite altimeter measurements. Different circulation regimes were investigated, including the “classical” anticyclonic eddy generated at the Channel narrows (16°S), the enhancement of southward migrating eddies by merging with structures (both cyclonic and anticyclonic) formed in the east of the Channel, and the presence of a fully developed cyclonic eddy at the Channel narrows. Comparison between in situ measurements (S-ADCP and velocities derived from surface drifters) and the geostrophic current derived from sea surface height measurements indicated that the latter can provide a reliable, quantitative description of eddy driven circulation in the MZC, with the exception that these currents are weaker by as much 30%. It is also suggested from in situ observation (drifters) that the departure from geostrophy of the surface circulation might be linked to strong wind conditions. Finally, our observations highlight that a-geostrophic currents need to be considered in future research to facilitate a more comprehensive description of the circulation in this area.
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Editeur Lieu de Publication Éditeur
Langue Langue du Résumé Titre Original
Éditeur de collection Titre de collection The Mozambique Channel: Mesoscale Dynamics and Ecosystem Responses Titre de collection Abrégé
Volume de collection 100 Numéro de collection Edition
ISSN 0967-0645 ISBN Médium
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Numéro d'Appel LL @ pixluser @ collection 388
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