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Bibliographie de l'Institut Maurice-Lamontagne

Poissons / Merluccius merluccius / Merlu européen, Merluche, Brochet de mer

TAMDRARI, H., M. CASTONGUAY, J.-C BRÊTHES, D. DUPLISEA, 2010. Density-independent and dependent habitat selection of Atlantic Cod (Gadus morhua) bases on geostatistical aggregation curves in the northern Gulf of St Lawrence. ICES J. Mar. Sci., 67(8): 1676-1686.

[Résumé disponible seulement en anglais]
Relationships were sought between local density and population abundance of Atlantic cod (Gadus morhua) in the northern Gulf of St Lawrence (Canada) over its entire area (4RS) and also within a subarea (4R) where the stock has concentrated since it collapsed during the early 1990s. Relationships were analysed using geostatistical aggregation curves computed within the two areas between years of contrasting abundance levels. The curves were interpreted in terms of four conceptual models of spatial dynamics: models D1 and D2, forced mainly by environmental heterogeneity, and models D3 and D4, in which individual behaviour is influenced by local density. Over the entire area, the cod population follows the D2 model for all years and age groups, and it is influenced by abiotic factors. Within the subarea, all four models applied, and the density-dependent basin model (D4) dominated from 2006 to 2008. The year 2006 seems to be pivotal because it coincides with the expansion of the cod population into its former area in the western Gulf (4S).©2010 International Council for the Exploration of the Sea. Published by Oxford Journals

DROUINEAU, H., S. MAHÉVAS, M. BERTIGNAC, D. DUPLISEA, 2010. A length-structured spatially explicit model for estimating hake growth and migration rates. ICES J. Mar. Sci., 67(8): 1697-1709.

[Résumé disponible seulement en anglais]
Despite an abundant literature, hake growth and migration remain poorly understood. A recent tagging campaign and an analysis of the growth increments on juvenile hake otoliths demonstrate that the growth rate has probably been largely underestimated. Migration rates have been studied through qualitative analysis of catch rate, but have not been confirmed by a more-quantitative analysis. Those biological uncertainties affect stock assessments and predictions by the uncertainty they bring to age–length keys and by hindering our ability to assess the impact of spatial management measures. Here, a spatially explicit length-structured model is developed to improve the biological knowledge of European hake (Merluccius merluccius), in terms specifically of migration and growth. The model belongs to the state–space class of models and is fitted by maximum likelihood on commercial landings, survey abundance indices, and tagging data. The estimated growth curve is close to estimates from tagging data, lending weight to the assumption of the species being fast-growing. Few migrations are long in distance, and there are none between the Bay of Biscay and the Celtic Sea. The model also demonstrates a high level of heterogeneity in the spatial distribution of spawning-stock biomass, with concentrations on the margins of the continental shelf.©2010 International Council for the Exploration of the Sea. Published by Oxford Journals

MORGAN, M.J., H. MURUA, G. KRAUS, Y. LAMBERT, G. MARTEINSDOTTIR, C.T. MARSHALL, L. O'BRIEN, J. TOMKIEWICZ, 2009. The evaluation of reference points and stock productivity in the context of alternative indices of stock reproductive potential. Can. J. Fish. Aquat. Sci., 66(3): 404-414 .

Nous explorons dans notre étude les effets de quatre indices de rechange du potentiel reproductif (RP) sur la perception de la productivité de la population chez huit populations de poissons provenant de l’Atlantique Nord. Les quatre indices de RP comprennent l’accroissement de la complexité biologique, l’addition de variation dans la maturation, la proportion des sexes et la fécondité. Le choix d’indice de RP affecte considérablement la perception de la productivité des stocks. Le statut de la population en fonction des points de référence, le RP par recrue et les projections de la taille de la population varient tous en fonction de l’indice RP retenu. Il n’y a pas de cohérence en ce qui a trait à quel indice donne l’estimation la plus élevée ou la plus basse de la productivité de la population, mais il y a plutôt des résultats différents selon l’importance de la variation dans la biologie de la reproduction et la composition en âge de la population. Les estimations des niveaux admissibles de récolte et du temps nécessaire au rétablissement des populations épuisées peuvent varier considérablement selon l’indice de RP utilisé.©2009 Presses scientifiques du CNRC