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Auteur Chassot, E.; Duplisea, D.; Hammill, M.; Caskenette, A.; Bousquet, N.; Lambert, Y.; Stenson, G. url  doi
openurl 
  Titre Role of predation by harp seals Pagophilus groenlandicus in the collapse and non-recovery of northern Gulf of St. Lawrence cod Gadus morhua Type Article scientifique
  Année 2009 Publication Revue Abrégée Mar. Ecol.-Prog. Ser.  
  Volume 379 Numéro Pages 279-297  
  Mots-Clés cod; functional response; harp seal; model; predation; recovery  
  Résumé A statistical catch-at-age model was developed to assess the effects of predation by the northwest Atlantic harp seal population on northern Gulf of St. Lawrence cod by estimating the relative importance of different sources of mortality that affected the stock during a period of collapse and non-recovery. Cod recruitment at age 1 is modeled via a non-linear stock-recruitment relationship based on total egg production and accounts for changes in female length-at-maturity and cod condition. Natural mortality other than seal predation also depends on cod condition used as an integrative index of changes in environmental conditions. The linkage between seals and cod is modeled through a multi-age functional response that was derived from the reconstruction of the seal diet using morphometric relationships and stomach contents of more than 200 seals collected between 1998 and 2001. The model was fitted following a maximum likelihood estimation approach to a scientific survey abundance index (1984 to 2006). Model results show that the collapse of the northern Gulf of St. Lawrence cod stock was mainly due to the combination of high fishing mortality rates and poor environmental conditions in the early to mid-1990s contributing to the current state of recruitment overfishing. The increase in harp seal abundance during 1984 to 2006 was reflected by an increase in predation mortality for the young cod age-groups targeted by seals. Although current levels of predation mortality affect cod spawning biomass, the lack of recovery of the NGSL cod stock seems mainly due to the very poor recruitment.  
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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 0171-8630 ISBN Médium  
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  Numéro d'Appel LL @ pixluser @ collection 15  
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Auteur Derolez, V.; Bec, B.; Munaron, D.; Fiandrino, A.; Pete, R.; Simier, M.; Souchu, P.; Laugier, T.; Aliaume, C.; Malet, N. url  doi
openurl 
  Titre Recovery trajectories following the reduction of urban nutrient inputs along the eutrophication gradient in French Mediterranean lagoons Type Article scientifique
  Année 2019 Publication Revue Abrégée Ocean & Coastal Management  
  Volume 171 Numéro Pages 1-10  
  Mots-Clés Coastal lagoons; Nutrients; Oligotrophication; Recovery; Urban inputs  
  Résumé French Mediterranean coastal lagoons have been subject to huge inputs of urban nutrients for decades leading to the eutrophication of these vulnerable ecosystems. In response to new environmental regulations, some of the lagoons have recently been the subject of large-scale management actions targeting the waste water treatment systems located on their watersheds. While the eutrophication of coastal ecosystems is well described, recovery trajectories have only recently been studied. To assess the rapidity and the extent of the effect of the remediation actions, we analysed data from a 14-year time series resulting from the monitoring of nutrients, biomass and the abundance of phytoplankton in the water column of French Mediterranean coastal lagoons covering the whole anthropogenic eutrophication gradient. Following a 50% to 80% reduction in total phosphorus (TP) and total nitrogen (TN) urban loadings from the watershed of hypertrophic and eutrophic ecosystems, the integrative parameters chlorophyll a, TN and TP, provide evidence for a rapid response (1 to 3 years) and for an almost complete recovery, suggesting no hysteresis for the eutrophic lagoon. However, our findings also show that recovery patterns depend on the eutrophication status before remediation and may include feedback responses. The different responses revealed by our results should help stakeholders prioritise remediation actions and identify appropriate restoration goals, especially in light of the targets of the Water Framework Directive (WFD).  
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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 0964-5691 ISBN Médium  
  Région Expédition Conférence  
  Notes Approuvé pas de  
  Numéro d'Appel MARBEC @ isabelle.vidal-ayouba @ collection 2493  
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Auteur Goetze, J.; Langlois, T.; Claudet, J.; Januchowski-Hartley, F.; Jupiter, S.D. doi  openurl
  Titre Periodically harvested closures require full protection of vulnerable species and longer closure periods Type Article scientifique
  Année 2016 Publication Revue Abrégée Biol. Conserv.  
  Volume 203 Numéro Pages 67-74  
  Mots-Clés areas; biomass; Fiji; Fisheries management; life-history; Locally managed marine areas; Marine conservation; marine reserves; predatory fish; Recovery; reef fish communities; responses; small-scale fisheries; stereo-video; vulnerability  
  Résumé Periodically harvested closures (PHCs) are small fisheries closures with objectives such as sustaining fisheries and conserving biodiversity and have become one of the most common forms of nearshore marine management in the Western Pacific. Although PHCs can provide both short-term conservation and fisheries benefits, their potential as a long-term management strategy remains unclear. Through empirical assessment of a single harvest event in each of five PHCs, we determined whether targeted fishes that differ in their vulnerability to fishing recovered to pre-harvest conditions (the state prior to last harvest) and demonstrated post-harvest recovery benefits after 1 year of re-closure. For low and moderately vulnerable species, two PHCs provided significant pre-harvest benefits and one provided significant post-harvest recovery benefits, suggesting a contribution to longer-term sustainability. PHCs with a combination of high compliance and longer closing times are more likely to provide fisheries benefits and recover from harvest events, however, no benefits were observed across any PHCs for highly vulnerable species. We recommend PHCs have longer closure periods before being harvested and species that are highly vulnerable to fishing (e.g. large species of; grouper, wrasse and parrotfish) are avoided during harvests to avoid overexploitation and increase the sustainability of small-scale fisheries. (C) 2016 Elsevier Ltd. All rights reserved.  
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  Langue English Langue du Résumé Titre Original  
  Éditeur de collection Titre de collection Titre de collection Abrégé  
  Volume de collection Numéro de collection Edition  
  ISSN 0006-3207 ISBN Médium  
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  Numéro d'Appel MARBEC @ alain.herve @ collection 1695  
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Auteur Goetze, J.S.; Januchowski-Hartley, F.A.; Claudet, J.; Langlois, T.J.; Wilson, S.K.; Jupiter, S.D. doi  openurl
  Titre Fish wariness is a more sensitive indicator to changes in fishing pressure than abundance, length or biomass Type Article scientifique
  Année 2017 Publication Revue Abrégée Ecol. Appl.  
  Volume 27 Numéro 4 Pages 1178-1189  
  Mots-Clés artisanal fisheries; Catch Efficiency; Compliance; Conservation; coral-reef management; Customary Management; fish behavior; Fisheries management; Flight Initiation Distance; flight initiation distance; indo-pacific; marine protected areas; periodically harvested closures; predatory fish; Recovery; risk-assessment; stereo-video system  
  Résumé Identifying the most sensitive indicators to changes in fishing pressure is important for accurately detecting impacts. Biomass is thought to be more sensitive than abundance and length, while the wariness of fishes is emerging as a new metric. Periodically harvested closures (PHCs) that involve the opening and closing of an area to fishing are the most common form of fisheries management in the western Pacific. The opening of PHCs to fishing provides a unique opportunity to compare the sensitivity of metrics, such as abundance, length, biomass and wariness, to changes in fishing pressure. Diver-operated stereo video (stereo-DOV) provides data on fish behavior (using a proxy for wariness, minimum approach distance) simultaneous to abundance and length estimates. We assessed the impact of PHC protection and harvesting on the abundance, length, biomass, and wariness of target species using stereo-DOVs. This allowed a comparison of the sensitivity of these metrics to changes in fishing pressure across four PHCs in Fiji, where spearfishing and fish drives are common. Before PHCs were opened to fishing they consistently decreased the wariness of targeted species but were less likely to increase abundance, length, or biomass. Pulse harvesting of PHCs resulted in a rapid increase in the wariness of fishes but inconsistent impacts across the other metrics. Our results suggest that fish wariness is the most sensitive indicator of fishing pressure, followed by biomass, length, and abundance. The collection of behavioral data simultaneously with abundance, length, and biomass estimates using stereo-DOVs offers a cost-effective indicator of protection or rapid increases in fishing pressure. Stereo-DOVs can rapidly provide large amounts of behavioral data from monitoring programs historically focused on estimating abundance and length of fishes, which is not feasible with visual methods.  
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  Langue English Langue du Résumé Titre Original  
  Éditeur de collection Titre de collection Titre de collection Abrégé  
  Volume de collection Numéro de collection Edition  
  ISSN 1051-0761 ISBN Médium  
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  Numéro d'Appel MARBEC @ alain.herve @ collection 2151  
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Auteur Le Fur, I.; De Wit, R.; Plus, M.; Oheix, J.; Derolez, V.; Simier, M.; Malet, N.; Ouisse, V. url  doi
openurl 
  Titre Re-oligotrophication trajectories of macrophyte assemblages in Mediterranean coastal lagoons based on 17-year time-series Type Article scientifique
  Année 2019 Publication Revue Abrégée Marine Ecology Progress Series  
  Volume 608 Numéro Pages 13-32  
  Mots-Clés Coastal lagoon; Long-term data series; Nutrient reduction; Recovery; Regime shift; Resilience; Restoration; Submerged aquatic vegetation  
  Résumé Since the mid-20th century, Mediterranean lagoons have been affected by eutrophication, leading to significant changes in primary producers. In the early 2000s, management actions have been implemented to reduce nutrient inputs with the aim to achieve a good ecological status as requested by the EU water framework directive. As a result of these actions, a sharp decline in nutrient loads has been recorded in several lagoons leading to an oligotrophication of the water column. The analyses of a long-term data set (1998-2015) of 21 polyhaline and euhaline lagoons with contrasting trophic status allowed us to infer a general scheme for the changes in macrophyte assemblages during the oligotrophication process. Placing hypertrophic and oligotrophic conditions end to end, we inferred that the general pattern for the re-oligotrophication trajectory in Mediterranean coastal lagoons is described by the following sequence, with regime shifts between each state: (1) bare non-vegetated sediments, phytoplankton-dominated state; (2) opportunistic macroalgae; (3) seagrass and perennial macroalgae dominated state. However, we did not observe the latter regime shift for the most eutrophicated lagoons, which, so far, remained stuck in the opportunistic macroalgae state. So far, the shift from dominance of opportunistic macroalgae to a system dominated by seagrasses was only observed in a single lagoon where seagrasses had never completely disappeared, which possibly relates to resilience. More generally, the conditions favoring regime shifts from opportunistic macroalgae to seagrasses are still poorly understood. In conclusion, we describe a generic pattern for re-oligotrophication of Mediterranean coastal lagoons, although a full recovery from highly eutrophied to oligotrophic conditions may require more than a decade and may include conditions that remain so far poorly recognized.  
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  Langue en Langue du Résumé Titre Original  
  Éditeur de collection Titre de collection Titre de collection Abrégé  
  Volume de collection Numéro de collection Edition  
  ISSN 0171-8630, 1616-1599 ISBN Médium  
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  Numéro d'Appel MARBEC @ isabelle.vidal-ayouba @ collection 2469  
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