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Auteur Ba, A.; Diouf, K.; Guilhaumon, F.; Panfili, J.
Titre Slow growth of the overexploited milk shark Rhizoprionodon acutus affects its sustainability in West Africa Type Article scientifique
Année 2015 Publication Revue Abrégée J Fish Biol
Volume 87 Numéro 4 Pages 912-929
Mots-Clés age; chondrichthyan; life-history traits; Senegal; vertebrae
Résumé Age and growth of Rhizoprionodon acutus were estimated from vertebrae age bands. From December 2009 to November 2010, 423 R. acutus between 37 and 112 cm total length (LT) were sampled along the Senegalese coast. Marginal increment ratio was used to check annual band deposition. Three growth models were adjusted to the length at age and compared using Akaike's information criterion. The Gompertz growth model with estimated size at birth appeared to be the best and resulted in growth parameters of L∞ = 139·55 (LT) and K = 0·17 year−1 for females and L∞ = 126·52 (LT) and K = 0·18 year−1 for males. The largest female and male examined were 8 and 9 years old, but the majority was between 1 and 3 years old. Ages at maturity estimated were 5·8 and 4·8 years for females and males, respectively. These results suggest that R. acutus is a slow-growing species, which render the species particularly vulnerable to heavy fishery exploitation. The growth parameters estimated in this study are crucial for stock assessments and for demographic analyses to evaluate the sustainability of commercial harvests.
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ISSN 1095-8649 ISBN Médium
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Numéro d'Appel MARBEC @ isabelle.vidal-ayouba @ collection 1417
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Auteur Ba, A.; Schmidt, J.; Deme, M.; Lancker, K.; Chaboud, C.; Cury, P.; Thiao, D.; Diouf, M.; Brehmer, P.
Titre Profitability and economic drivers of small pelagic fisheries in West Africa: A twenty year perspective Type Article scientifique
Année 2017 Publication Revue Abrégée Mar. Pol.
Volume 76 Numéro Pages 152-158
Mots-Clés Income; management; Senegal; small pelagic fish; Small scale fisheries
Résumé Small pelagics are the main fish resource in North West Africa. In Senegal, these are mainly sardinellas (Sardinella aurita and S. maderensis) and bonga shad (Ethmalosa fimbriata). The fisheries, mainly encircling gillnets and purse seines, are predominantly performed by artisanal fishers and are of great importance for the Senegalese economy and for food security in the region. However, in recent years, the main conditions for these fisheries have changed and recent observations have shown strong declines in profit. An analysis over the last twenty years (1993-2013) show that the fisheries lost profit between 65% and 100% while operating costs increased by 25% and 90%, for encircling gillnet and purse seine, respectively. While the fuel price dominates as determining factor during the survey period, important other drivers during the last five years were a decrease in fish biomass and an increase in fishing effort.
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ISSN 0308-597x ISBN Médium
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Numéro d'Appel MARBEC @ alain.herve @ collection 2089
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Auteur Diankha, O.; Demarcq, H.; Fall, M.; Thiao, D.; Thiaw, M.; Sow, B.A.; Gaye, A.T.; Brehmer, P.
Titre Studying the contribution of different fishing gears to the Sardinella small-scale fishery in Senegalese waters Type Article scientifique
Année 2017 Publication Revue Abrégée Aquat. Living Resour.
Volume 30 Numéro Pages 27
Mots-Clés abundance; africa; aurita; catch; dynamics; Effects of fishing; environmental-factors; Generalized additive model; generalized additive-models; patterns; Pelagic fish; Purse seine; retention; Sardinella aurita; Sardinella maderensis; Senegal; Surrounding gillnet
Résumé This study investigated variations of landings of two key species, Sardinella aurita and Sardinella maderensis, in Senegalese waters over a ten-year period (2004-2013). Using generalized additive models, it was found that fishing gear played a major role in explaining differences in monthly landings for both species (51-71% deviance explained). Its effect was more significant in the southern part of Senegal. Fishing effort (number of trips) accounted only for 4-18% of variability in landings. Purse seine (PS) fishing was the most important contributor to the landings of both species. In addition, in the southern area, surrounding gillnet fishing was also important for S. maderensis. Modeling results showed that the relationship between monthly effort and landings was generally positive and leveling off, while it was dome shaped for PSs and surrounding gillnets. Thus, when estimating fishing effort indices for management in Senegal, it is necessary to account for differences in fishing gears and the non-linear relationship between fishing effort and landings.
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ISSN 0990-7440 ISBN Médium
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Numéro d'Appel MARBEC @ alain.herve @ collection 2168
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Auteur Ecoutin, J.-M.; Simier, M.; Albaret, J.-J.; Laë, R.; Morais, L.T. de
Titre Changes over a decade in fish assemblages exposed to both environmental and fishing constraints in the Sine Saloum estuary (Senegal) Type Article scientifique
Année 2010 Publication Revue Abrégée Estuarine, Coastal and Shelf Science
Volume 87 Numéro Pages 284-292
Mots-Clés Biomasse; De; Diversite; Ecologique; Estuaire; Impact; Indicateur; L'Environnement; Niveau; Peche; Poisson; Saloum; Senegal; Sine; Specifique; Surexploitation; Trophique
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ISSN 0272-7714 ISBN Médium
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Numéro d'Appel LL @ pixluser @ collection 70
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