4 resultados para Estimation du maximum de vraisemblance

em Archimer: Archive de l'Institut francais de recherche pour l'exploitation de la mer


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The aim of this report is to provide biomass estimates (AFDW, g.m-2 ) of the four main components of the benthic food web in the southern part of the Bay of St-Brieuc: suspension-feeders, deposit-feeders, herbivores and carnivores. Patterns in the environmental data (i.e., sedimentary characters) are first analysed, and then related to the spatial distribution of communities ; both approaches use classical ordination techniques (PCA, correspondence analysis). A second typology, based on a review of published litterature concerning coastal macrozoobenthos feeding, ascribes each taxonomic unit to a trophic group. Finally, quantitative results are thus given per biota ; suspension-feeders appear to dominate (in terms of biomass) most of fine-sand habitats of the studied area.

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Le présent rapport est une nouvelle version du rapport intitulé « Estimation de l’exploitation halieutique des navires de pêche français ». Il restitue les résultats des traitements des « données VMS » en offrant une précision spatiale accrue en matière d’occupation de l’espace marin, d’origine géographique des débarquements, et de dépendance des navires à certains secteurs de pêche.

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The coastal zone of the Nord – Pas de Calais / Picardie showed dysfonctioning patterns of the ecosystem considered to be link to human activities along shores. These results in regular massive development of species, such as the phytoplanktonic seaweed, Phaeocystis sp. which life cycle was partly linked to nutrients availability and consequently to anthropogenic inputs. As part of the evaluation of the influence of continental inputs on the marine environment (nitrates, phosphates,…) and on potential eutrophication processes, of the estimation of the efficiency of the sewage treatments plants in the possible elimination of dumpings and in order to establish a long-term survey to follow up the change in coastal waters quality, the regional nutrients monitoring network was implemented by Ifremer in collaboration with the Agence de l'Eau Artois-Picardie in 1992 in order to complete the REPHY (Phytoplankton and Phycotoxins) monitoring programme. This study reports the main results for the year 2015 in terms of temporal change of the main physico-chemical and biological parameters characteristic of water masses sampled along three transects offshore Dunkerque, Boulogne-sur-Mer and the Bay of Somme.

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In this paper are given the first results of a quantitative study of the spawning of Pilchard Sardina pilchardus in the Gulf of Lion~during Winter 1975 and Winter 1976. The mean density of eggs at each station and their average abundance in the spawning area were estimated. The incubation time of eggs depending upon temperature was also calculated. En 1975 et 1976 une étude de la reproduction de la sardine dans le Golfe du Lion a été réalisée. Les premiers résultats de cette étude, qui a pour but d'évaluer quantitativement la ponte de cette espèce, permettent de donner une estimation moyenne de l'abondance des oeufs au cours d'une campagne. La durée de l'incubation en fonction de la tempé­rature a d'autre part été déterminée.