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Auteur Hoffle, H.; Van Damme, C.J.G.; Fox, C.; Lelievre, S.; Loots, C.; Nash, R.D.M.; Vaz, S.; Wright, P.J.; Munk, P.
Titre Linking spawning ground extent to environmental factors – patterns and dispersal during the egg phase of four North Sea fishes Type Article scientifique
Année 2018 Publication Revue Abrégée Can. J. Fish. Aquat. Sci.
Volume 75 Numéro 3 Pages 357-374
Mots-Clés climate-change; spatial distributions; cod gadus-morhua; neighbor matrices; offshore oil; generalized additive-models; dependent development rates; haddock melanogrammus-aeglefinus; pleuronectes-platessa l; whiting merlangius-merlangus
Résumé Previous studies have shown that four commercially important demersal species, namely Atlantic cod (Gadus morhua), haddock (Melanogrammus aeglefinus), whiting (Merlangius merlangus), and European plaice (Pleuronectes platessa), spawn in distinct areas across the North Sea. Based on two comprehensive ichthyoplankton surveys in 2004 and 2009, the present study uses generalized additive mixed models to delimit these spawning grounds using the distribution of recently spawned eggs, investigates their relationship to specific environmental conditions, and examines egg dispersal during their development. Results indicate that presence-absence of early stage eggs is more related to temporal and topographic variables, while egg densities are closely linked with hydrography. Egg distribution patterns were relatively consistent during development and only changed near hatching. Compared with historic observations, the location of the spawning grounds appeared stable on the broad scale but centres of egg abundance varied between the surveyed years. Potential effects of long-term climate change and anthropogenic short-term disturbances, such as seismic surveys, on fish reproduction are discussed, pointing out the demand for multispecies studies on these issues.
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Auteur institutionnel Thèse
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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 0706-652x ISBN Médium
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Numéro d'Appel MARBEC @ alain.herve @ collection 2316
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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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Auteur institutionnel Thèse
Editeur Lieu de Publication Éditeur
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 0990-7440 ISBN Médium
Région Expédition Conférence
Notes (up) Approuvé pas de
Numéro d'Appel MARBEC @ alain.herve @ collection 2168
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