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Auteur (up) Annasawmy, P.; Ternon, J.-F.; Cotel, P.; Cherel, Y.; Romanov, E.; Roudaut, G.; Lebourges-Dhaussy, A.; Menard, F.; Marsac, F. doi  openurl
  Titre Micronekton distributions and assemblages at two shallow seamounts of the south-western Indian Ocean: Insights from acoustics and mesopelagic trawl data Type Article scientifique
  Année 2019 Publication Revue Abrégée Prog. Oceanogr.  
  Volume 178 Numéro Pages 102161  
  Mots-Clés Acoustics; deep-scattering layer; diel migration; fish aggregations; mesoscale features; Micronekton; mozambique channel; myctophid fishes; pelagic communities; Seamount; Seamount-associated fauna; South-western Indian Ocean; species identification; target strength; vertical-distribution  
  Résumé Micronekton distributions and assemblages were investigated at two shallow seamounts of the south-western Indian Ocean using a combination of trawl data and a multi-frequency acoustic visualisation technique. La Pa rouse seamount (summit depth similar to 60 m) is located on the outskirts of the oligotrophic Indian South Subtropical Gyre (ISSG) province with weak mesoscale activities and low primary productivity all year round. The “MAD-Ridge” seamount (thus termed in this study; similar to 240 m) is located in the productive East African Coastal (EAFR) province with high mesoscale activities to the south of Madagascar. Higher micronekton species richness was recorded at MAD-Ridge compared to La Perouse. Resulting productivity at MAD-Ridge seamount was likely due to the action of mesoscale eddies advecting productivity and larvae from the Madagascar shelf rather than local dynamic processes such as Taylor column formation. Mean micronekton abundance/biomass, as estimated from mesopelagic trawl catches, were lower over the summit compared to the vicinity of the seamounts, due to net selectivity and catchability and depth gradient on micronekton assemblages. Mean acoustic densities in the night shallow scattering layer (SSL: 10-200 m) over the summit were not significantly different compared to the vicinity (within 14 nautical miles) of MAD-Ridge. At La Perouse and MAD-Ridge, the night and day SSL were dominated by common diel vertically migrant and non-migrant micronekton species respectively. While seamount-associated mesopelagic fishes such as Diaphus suborbitalis (La Perouse and MAD-Ridge) and Benthosema fibula= performed diel vertical migrations (DVM) along the seamounts' flanks, seamount-resident benthopelagic fishes, including Cookeolus japonicus (MAD-Ridge), were aggregated over MAD-Ridge summit. Before sunrise, mid-water migrants initiated their vertical migration from the intermediate to the deep scattering layer (DSL, La Perouse: 500-650 m; MAD-Ridge: 400-700 m) or deeper. During sunrise, the other taxa contributing to the night SSL exhibited a series of vertical migration events from the surface to the DSL or deeper until all migrants have reached the DSL before daytime. Possible mechanisms leading to the observed patterns in micronekton vertical and horizontal distributions are discussed. This study contributes to a better understanding of how seamounts influence the DVM, horizontal distribution and community composition of micronekton and seamount-associated/resident species at two poorly studied shallow topographic features in the south-western Indian Ocean.  
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  ISSN 0079-6611 ISBN Médium  
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  Notes WOS:000496861900013 Approuvé pas de  
  Numéro d'Appel MARBEC @ isabelle.vidal-ayouba @ collection 2666  
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Auteur (up) Arones, K.; Grados, D.; Ayon, P.; Bertrand, A. doi  openurl
  Titre Spatio-temporal trends in zooplankton biomass in the northern Humboldt current system off Peru from 1961-2012 Type Article scientifique
  Année 2019 Publication Revue Abrégée Deep-Sea Res. Part II-Top. Stud. Oceanogr.  
  Volume 169 Numéro Pages Unsp-104656  
  Mots-Clés anchovy engraulis-ringens; chile; current ecosystem; Decadal trends; diet; Macrozooplankton; Mesozooplankton; Regime-shift; sardine; Secondary production; Spatiotemporal distribution; volume; zone  
  Résumé Anchovy (Engraulis ringens) is the most important exploited fish species in the Northern Humboldt Current System (NHCS) off Peru. This species, as well as most other pelagic resources, mainly forage on zooplankton. The NHCS is bottom-up controlled at a variety of scales. Therefore, fish biomass is driven by the abundance of their prey. In this context, we studied the spatiotemporal patterns of zooplankton biomass in the NHCS from 1961-2012. Data were collected with Hensen net all along the Peruvian coast. To transform zooplankton biovolume into biomass we used a regression that was calibrated from 145 zooplankton samples collected during four surveys and, for which, precise information was available on both biovolume and wet weight. The regression model was then applied on a time-series encompassing 158 cruises performed by the Peruvian Institute of the Sea (IMARPE) between 1961 and 2012. We observed a clear multidecadal pattern and two regime shifts, in 1973 and 1992. Maximum biomass occurred between 1961 and 1973 (61.5 g m(-2)). The lowest biomass (17.8 g m(-2)) occurred between 1974 and 1992. Finally, the biomass increased after 1993 (26.6 g m(-2)) but without reaching the levels observed before 1973. A seasonal pattern was observed with significantly more biomass in spring than in other seasons. Spatially, zooplankton biomass was higher offshore and in northern and southern Peru. Interestingly, the zooplankton sampling was performed using classic zooplankton net that are well fitted to mesozooplankton and are known to underestimate the macrozooplankton; however, the spatiotemporal patterns we observed are consistent with those of macrozooplankton, in particular euphausiids. This suggests that in the NHCS, when and where macrozooplankton dominates it also dominates the biomass obtained using classic zooplankton net samples. Finally, until now, in the NHCS only time-series on zooplankton biovolume were available. The biomass data we provide are more directly usable in trophic or end-to-end models.  
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  ISSN 0967-0645 ISBN Médium  
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  Notes WOS:000504782200009 Approuvé pas de  
  Numéro d'Appel MARBEC @ isabelle.vidal-ayouba @ collection 2693  
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Auteur (up) Arroyo, N.-L.; Safi, G.; Vouriot, P.; López-López, L.; Niquil, N.; Le Loc’h, F.; Hattab, T.; Preciado, I. url  doi
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  Titre Towards coherent GES assessments at sub-regional level: signs of fisheries expansion processes in the Bay of Biscay using an OSPAR food web indicator, the mean trophic level Type Article scientifique
  Année 2019 Publication Revue Abrégée ICES J Mar Sci  
  Volume 76 Numéro 6 Pages 1543-1553  
  Mots-Clés  
  Résumé Abstract. Using the Bay of Biscay (BoB) as a case study, we conducted a transnational assessment of the mean trophic level (MTL, Ospar FW4) indicator at sub-re  
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  Numéro d'Appel MARBEC @ isabelle.vidal-ayouba @ collection 2544  
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Auteur (up) Aubin, J.; Callier, M.; Rey-Valette, H.; Mathe, S.; Wilfart, A.; Legendre, M.; Slembrouck, J.; Caruso, D.; Chia, E.; Masson, G.; Blancheton, J.P.; Ediwarman; Haryadi, J.; Prihadi, T.H.; Casaca, J. de M.; Tamassia, S.T.J.; Tocqueville, A.; Fontaine, P. doi  openurl
  Titre Implementing ecological intensification in fish farming: definition and principles from contrasting experiences Type Article scientifique
  Année 2019 Publication Revue Abrégée Rev. Aquac.  
  Volume 11 Numéro 1 Pages 149-167  
  Mots-Clés agriculture; agroecology; animal production; aquaculture systems; ecosystem services; emergy accounting; environmental-impact; information; life cycle assessment; life-cycle assessment; mekong delta; perception; responsible aquaculture; sustainable aquaculture; system  
  Résumé Ecological intensification is a new concept in agriculture that addresses the double challenge of maintaining a level of production sufficient to support needs of human populations and respecting the environment in order to conserve the natural world and human quality of life. This article adapts this concept to fish farming using agroecological principles and the ecosystem services framework. The method was developed from the study of published literature and applications at four study sites chosen for their differences in production intensity: polyculture ponds in France, integrated pig and pond polyculture in Brazil, the culture of striped catfish in Indonesia and a recirculating salmon aquaculture system in France. The study of stakeholders' perceptions of ecosystem services combined with environmental assessment through Life Cycle Assessment and Emergy accounting allowed development of an assessment tool that was used as a basis for co-building evolution scenarios. From this experience, ecological intensification of aquaculture was defined as the use of ecological processes and functions to increase productivity, strengthen ecosystem services and decrease disservices. It is based on aquaecosystem and biodiversity management and the use of local and traditional knowledge. Expected consequences for farming systems consist of greater autonomy, efficiency and better integration into their surrounding territories. Ecological intensification requires territorial governance and helps improve it from a sustainable development perspective.  
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  ISSN 1753-5123 ISBN Médium  
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  Numéro d'Appel MARBEC @ isabelle.vidal-ayouba @ collection 2537  
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Auteur (up) Audouit, C.; Pasqualini, V.; De Wit, R.; Flanquart, H.; Deboudt, P.; Rufin-Soler, C. url  doi
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  Titre Comparing social representation of water quality in coastal lagoons with normative use of ecological indicators Type Article scientifique
  Année 2019 Publication Revue Abrégée Marine Policy  
  Volume 101 Numéro Pages 137-146  
  Mots-Clés  
  Résumé Coastal lagoons are important for coastal and marine biodiversity. Nevertheless, they are very sensitive and vulnerable to human impacts, which often result in a decrease of their biodiversity and degradation of their water quality. Considering recent efforts for ecological restoration of coastal lagoons, it appears appropriate to compare the social representations of users of the coastal lagoons and of inhabitants, with ecological diagnoses of biodiversity and water quality. The main question is whether there is congruence between water quality defined by environmental criteria on one hand and the social representations of these issues by lagoon users and local populations on the other hand? How can we explain the social representations of lagoons concerning landscape, water quality and biodiversity? This study was focused on two Mediterranean lagoon areas, i.e., the Palavas lagoon complex (Gulf of Lions) and Biguglia lagoon (Corsica). We have documented these changes of ecosystem states using the criteria of regional monitoring programs that anticipated the implementation of the Water Framework Directive (WFD). Accordingly, both systems have shown bad water quality in the past with recent improvements. For studying the social representations, we conducted 267 surveys with lagoon inhabitants that live close to the lagoons and users of these spaces. In general, most of the residents living close to the lagoons considered that water quality is moderate to good, that biodiversity is good to high and that the current situation is better than in the past. However, some discrepancies between social representations and ecological diagnoses were observed.  
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  ISSN 0308-597x ISBN Médium  
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  Numéro d'Appel MARBEC @ isabelle.vidal-ayouba @ collection 2187  
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