Data/hora: 05/06/2024 10:40:41

Provedor de dados: | 5
País: | France
Título: | Modélisation écologique des populations de palourdes roses (Paphia rhomboïdes) et d'amandes de mer (Glycymeris glycymeris) en Manche
Autores: | Savina, Marie.
Data: | 2004-06-07
Ano: | 2004
Palavras-chave: | Shellfish fisheries; Growth; Ecophysiology; Distribution of benthic invertebrates; Numerical ecological space distributed deterministic modelling; Glycymeris glycymeris; Paphia rhomboïdes; Golfe Normand Breton; Channel Sea; Exploitation des bivalves sauvages; Croissance; Ecophysiologie; Répartition des invertébrés benthiques; Modélisation numérique écologique spatialisée déterministe; Glycymeris glycymeris; Paphia rhomboïdes; Golfe Normand Breton; Manche.
Resumo: | Diversity and abundance of the benthic fauna in the Channel Sea have favoured the development of fisheries, particularly those of shellfish (scallop, warty venus, common cockle, dog cockle, banded carpet shell, surf clam...) and also attracted the interest of scientists. Some large scientific programs were carried out in the seventies to study benthos distribution in this area. Among the main listed bivalves, the dog cockle (Glycymeris glycymeris) and the banded carpet shell (Paphia rhomboïdes) are particularly widespread in the Channel Sea and in the "Golfe Normand-Breton", where they are ones of the most abundant species in terms of biomass. In view of their halieutic interest and the existence of an important database describing their distribution, biology and ecology, these species are especially interesting for studying the distribution of invertebrates in the Channel Sea.   The first part of this work consisted of completing and/or updating the available data on both species:   * Stock assessment data from cruises performed during the eighties and nineties, in addition to those realised during this work, allowed the evolution of both species populations to be described over 20 years, and to highlight some demographic features and the effects of harvesting for each species in the "Golfe Normand-Breton".      * Additionally, studies were carried out on the growth in the "Golfe Normand-Breton" in order to compare the two species, and to identify the environmental parameters controlling growth:          - An ecophysiological study to measure the main nutrition and respiration parameters and their variations as a function of environmental parameters (temperature and food concentration);          - A comparative study of both bivalves weight and size in different areas of the site to study the influence of environmental parameters (temperature, food concentration, particulate inorganic matter concentration, bivalve density...) on the growth of individuals.  The modelling part of the work consisted of two components:   * Development of an ecophysiological model for each species to reproduce their growth in the different areas of the "Golfe Normand-Breton" throughout their whole benthic life. The parameters came from the ecophysiological study data, and the results were compared with the data obtained during the comparative growth study.     * Development of a population dynamics model for each species, space-distributed in the Channel Sea, which describes their whole life cycle (both planktonic and benthic stages) with a mechanistic and deterministic approach. The aim was to reproduce the actual average distribution of the populations. From a theoretical initial situation, this model runs until a steady state is reached, using a standard meteorological year repeatedly. For each species, the population dynamics model includes an ecophysiological sub-unit to model mortality and fecundity of benthic animals, and the whole is linked to a hydraulic and primary production box model (Hoch, 1998). The state variables used are: density (individuals.m-2 or individuals.m-3 for larvae) and average soft body dry weight for each age class (only for benthic animals).  In the case of P. rhomboïdes, the model reproduces the main features of the species distribution in the Channel Sea, particularly its abundance in the "Golfe Normand-Breton" and in the south part of eastern Channel, and its scarcity in the western Channel, mainly linked to food deficiency. For G. glycymeris, the model is not efficient in reproducing the observed distribution, mainly because of some problems in defining the ecophysiological component.
Tipo: | Text
Idioma: | Francês

Identificador:

https://archimer.ifremer.fr/doc/2004/these-1.pdf

https://archimer.ifremer.fr/doc/00000/1/

Editor: | Université d'Aix-Marseille II
Formato: | application/pdf

Fonte:

info:eu-repo/semantics/openAccess

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