Éditeur(s) : ISTPM
Résumé : Abundance and biomass of an unexploited ormer population in the vicinity of Saint-Malo (northern Brittany) are estimated using a stratified sampling technique. Examinations are made be diving at 200 sites. The mean biomass of the population is about 400 tons but the stock is not evenly distributed over the studied area: the greatest densities are observed on schist substrate. Size and weight frequency distribution reveal a "top-heave" structure due to an accumulation of old individuals with low production.
Un échantillonnage stratifié, portant sur 200 stations prospectées en plongée, a été mis en oeuvre dans la région de Saint-Malo (Bretagne nord) pour estimer les caractéristiques de la population d'ormeaux. La biomasse moyenne de celle-ci a été évaluée à 400 tonnes environ mais elle est répartie de manière hétérogène sur la zone étudiée, les fonds de nature schisteuse apparaissant les plus favorables à l'espèce. L'examen des distributions de fréquence de taille et de poids révèle globalement une forte proportion d'individus âgés constituant une biomasse accumulée peu productive.
Revue des Travaux de l'Institut des Pêches Maritimes (0035-2276) (ISTPM), 1984-06 , Vol. 48 , N. 3-4 , P. 95-105

Droits : Ifremer
http://archimer.ifremer.fr/doc/1984/publication-1793.pdf
http://archimer.ifremer.fr/doc/00000/1793/

Éditeur(s) : Oxford Univ Press
Résumé : The impact of the fishing effort exerted by a vessel on a population depends on catchability, which depends on population accessibility and fishing power. The work investigated whether the variation in fishing power could be the result of the technical characteristics of a vessel and/or its gear or whether it is a reflection of inter-vessel differences not accounted for by the technical attributes. These inter-vessel differences could be indicative of a skipper/crew experience effect. To improve understanding of the relationships, landings per unit effort (lpue) from logbooks and technical information on vessels and gears (collected during interviews) were used to identify variables that explained variations in fishing power. The analysis was undertaken by applying a combination of generalized additive models and generalized linear models to data from several European fleets. The study highlights the fact that taking into account information that is not routinely collected, e. g. length of headline, weight of otter boards, or type of groundrope, will significantly improve the modelled relationships between lpue and the variables that measure relative fishing power. The magnitude of the skipper/crew experience effect was weaker than the technical effect of the vessel and/or its gear.
Ices Journal Of Marine Science (1054-3139) (Oxford Univ Press), 2011-11 , Vol. 68 , N. 10 , P. 2252-2263

Droits : 2011 International Council for the Exploration of the Sea. Published by Oxford University Press. All rights reserved.
http://archimer.ifremer.fr/doc/00049/16043/15172.pdf
DOI:10.1093/icesjms/fsr150
http://archimer.ifremer.fr/doc/00049/16043/