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Auteur Campbell, S.J.; Darling, E.S.; Pardede, S.; Ahmadia, G.; Mangubhai, S.; Amkieltiela; Estradivari; Maire, E. doi  openurl
  Titre Fishing restrictions and remoteness deliver conservation outcomes for Indonesia's coral reef fisheries Type Article scientifique
  Année 2020 Publication Revue Abrégée Conserv. Lett.  
  Volume Numéro Pages e12698  
  Mots-Clés data-poor fisheries; dynamics; food webs; gear restrictions; management; marine protected areas; small-scale fisheries; South East Asia; targets  
  Résumé Coral reef fisheries depend on reef fish biomass to support ecosystem functioning and sustainable fisheries. Here, we evaluated coral reefs across 4,000 km of the Indonesian archipelago to reveal a large gradient of biomass, from 17,000 kg/ha. Trophic pyramids characterized by planktivore dominance emerged at high biomass, suggesting the importance of pelagic pathways for reef productivity. Total biomass and the biomass of most trophic groups were higher within gear restricted and no-take management, but the greatest biomass was found on unmanaged remote reefs. Within marine protected areas (MPAs), 41.6% and 43.6% of gear restricted and no-take zones, respectively, met a global biomass target of 500 kg/ha, compared with 71.8% of remote sites. To improve conservation outcomes for Indonesia's biodiverse and economically important coral reef fisheries, our results suggest to: (1) strengthen management within Indonesia's existing MPAs and (2) precautionarily manage remote reefs with high biomass.  
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  ISSN 1755-263x ISBN Médium  
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  Numéro d'Appel MARBEC @ isabelle.vidal-ayouba @ collection (down) 2733  
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Auteur Hill, S.L.; Hinke, J.; Bertrand, S.; Fritz, L.; Furness, R.W.; Ianelli, J.N.; Murphy, M.; Oliveros‐Ramos, R.; Pichegru, L.; Sharp, R.; Stillman, R.A.; Wright, P.J.; Ratcliffe, N. url  doi
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  Titre Reference points for predators will progress ecosystem-based management of fisheries Type Article scientifique
  Année 2020 Publication Revue Abrégée Fish and Fisheries  
  Volume 21 Numéro 2 Pages 368-378  
  Mots-Clés adaptive management; Aichi Biodiversity Targets; ecosystem interactions; indirect impacts; management strategy; precautionary approach  
  Résumé Ecosystem-based management of fisheries aims to allow sustainable use of fished stocks while keeping impacts upon ecosystems within safe ecological limits. Both the FAO Code of Conduct for Responsible Fisheries and the Aichi Biodiversity Targets promote these aims. We evaluate implementation of ecosystem-based management in six case-study fisheries in which potential indirect impacts upon bird or mammal predators of fished stocks are well publicized and well studied. In particular, we consider the components needed to enable management strategies to respond to information from predator monitoring. Although such information is available in all case-studies, only one has a reference point defining safe ecological limits for predators and none has a method to adjust fishing activities in response to estimates of the state of the predator population. Reference points for predators have been developed outside the fisheries management context, but adoption by fisheries managers is hindered a lack of clarity about management objectives and uncertainty about how fishing affects predator dynamics. This also hinders the development of adjustment methods because these generally require information on the state of ecosystem variables relative to reference points. Nonetheless, most of the case-studies include precautionary measures to limit impacts on predators. These measures are not used tactically and therefore risk excessive restrictions on sustainable use. Adoption of predator reference points to inform tactical adjustment of precautionary measures would be an appropriate next step towards ecosystem-based management.  
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  ISSN 1467-2979 ISBN Médium  
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  Numéro d'Appel MARBEC @ isabelle.vidal-ayouba @ collection (down) 2684  
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Auteur Saeedi, H.; Reimer, J.D.; Brandt, M.; Dumais, P.-O.; Jazdzewska, A.M.; Jeffery, N.W.; Thielen, P.M.; Costello, M.J. doi  openurl
  Titre Global marine biodiversity in the context of achieving the Aichi Targets: ways forward and addressing data gaps Type Article scientifique
  Année 2019 Publication Revue Abrégée PeerJ  
  Volume 7 Numéro Pages e7221  
  Mots-Clés Aichi targets; assemblages; benefits; Biodiversity tools and pipelines; Biogeography; conservation; coral-reefs; Data standard; Data standards; deep-sea; Discovery; Dissemination; diversity gradient; life; Marine biodiversity; patterns; Prediction; progress; species richness; Stewardship; Stewardship and dissemination; Tools and pipelines  
  Résumé In 2010, the Conference of the Parties of the Convention on Biological Diversity agreed on the Strategic Plan for Biodiversity 2011-2020 in Aichi Prefecture, Japan. As this plan approaches its end, we discussed whether marine biodiversity and prediction studies were nearing the Aichi Targets during the 4th World Conference on Marine Biodiversity held in Montreal, Canada in June 2018. This article summarises the outcome of a five-day group discussion on how global marine biodiversity studies should be focused further to better understand the patterns of biodiversity. We discussed and reviewed seven fundamental biodiversity priorities related to nine Aichi Targets focusing on global biodiversity discovery and predictions to improve and enhance biodiversity data standards (quantity and quality), tools and techniques, spatial and temporal scale framing, and stewardship and dissemination. We discuss how identifying biodiversity knowledge gaps and promoting efforts have and will reduce such gaps, including via the use of new databases, tools and technology, and how these resources could be improved in the future. The group recognised significant progress toward Target 19 in relation to scientific knowledge, but negligible progress with regard to Targets 6 to 13 which aimed to safeguard and reduce human impacts on biodiversity.  
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  ISSN 2167-8359 ISBN Médium  
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  Numéro d'Appel MARBEC @ isabelle.vidal-ayouba @ collection (down) 2682  
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Auteur 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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Auteur Brehmer, P.; Sarre, A.; Guennegan, Y.; Guillard, J. doi  openurl
  Titre Vessel Avoidance Response: A Complex Tradeoff Between Fish Multisensory Integration and Environmental Variables Type Article scientifique
  Année 2019 Publication Revue Abrégée Rev. Fish. Sci. Aquac..  
  Volume 27 Numéro 3 Pages 380-391  
  Mots-Clés acoustic backscatter; always encounter; behavior; boat noise; cod; fish behavior; fish school; fisheries acoustics; gadus-morhua; multibeam sonar; pelagic fish; school structure; silent ships sometimes; small pelagic assessment; target strength; Vessel avoidance  
  Résumé The avoidance reaction by fish in front of an approaching vessel is a major source of bias in direct biomass assessment and ecological studies based on fisheries acoustics data. An experiment was carried out to compare echosounder data obtained using a small speedboat and a research fisheries vessel generating significant higher noise above conventional reduced-noise standard. The results show that there was no significant difference between the individual fish target strength distributions, and the numbers of schools recorded by both boats, these schools having similar areas and perimeters. However, the schools detected by the noisier vessel were significantly deeper, and unexpectedly had a significantly higher energy level. These findings suggest that noise-reduced vessels trigger a different vessel avoidance reaction. The noise-reduction standard is not sufficient to reduce avoidance behavior. It is also to take into consideration the ambient noise, which could impair perception of the platform by the fish, and the probability that the acoustic stimuli could be less important than visual perception under some local conditions. The paper introduces the concept of partial avoidance and presents a conceptual diagram of the strength of the avoidance reaction. Last, it is not recommended, because of noise reasons, that vessels routinely used for pelagic stock assessment surveys be changed. Indeed standardized time series, which could be disrupted when switching to a new vessel, are more important than the hypothetical gain from change to quieter vessels. Obviously, all long-term surveys must change vessels; best practice will be to estimate the vessel effect before any change to avoid disrupting the time series and/or perform vessel intercalibration surveys.  
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  ISSN 2330-8249 ISBN Médium  
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  Numéro d'Appel MARBEC @ isabelle.vidal-ayouba @ collection (down) 2603  
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