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Bibliographie de l'Institut Maurice-Lamontagne

Poissons / Pollachius virens / Goberge, Lieu noir, Colin noir

BUI, A.O.V., M. CASTONGUAY, P. OUELLET, J.-M SÉVIGNY, 2011. Searching for Atlantic Cod (Gadus morhua) spawning sites in the northwest Gulf of St Lawrence (Canada) using molecular techniques. ICES J. Mar. Sci., 68(5): 911-918.

[Résumé disponible seulement en anglais]
The overexploitation of Atlantic cod (Gadus morhua) in the Northwest Atlantic led to the collapse of most stocks and the demise of spawning components in the early 1990s. In the northern Gulf of St Lawrence, the spawning component of Northwest Atlantic Fishery Organization Division 4S was believed no longer to exist after the collapse. To verify this hypothesis, we used molecular techniques to identify cod, haddock, and witch flounder (CHW) eggs precisely, in an attempt to locate the potential remaining spawning sites for cod in the northwest Gulf. Ichthyoplankton surveys were conducted in spring from 2005 to 2008. Results were compared with those of surveys that took place in spring in the same area 20 years earlier to determine if there had been any changes in spawning location and egg abundance. Atlantic cod made up the majority (97 %) of CHW eggs identified. The presence of stage I cod eggs proved that there is still a cod spawning component in the northwest Gulf of St Lawrence, but egg abundance has declined by about an order of magnitude compared with the 1980s. There was no obvious difference in the location of cod spawning grounds between the two decades

MORISSETTE, L., M. CASTONGUAY, C. SAVENKOFF, D.P. SWAIN, D. CHABOT, H. BOURDAGES, M.O. HAMMILL, J. MARK HANSON, 2009. Contrasting changes between the northern and southern Gulf of St. Lawrence ecosystems associated with the collapse of groundfish stocks. Deep-Sea Res., Part II, Top. Stud. Oceanogr., 56(21-22): 2117-2131.

[Résumé disponible seulement en anglais]
In order to have a global view of ecosystem changes associated with the collapse of groundfish species in the Gulf of St.Lawrence during the early 1990s, Ecopath mass balance models were constructed in corporating uncertainty in the input data.These models covered two ecosystems (northern and southern Gulf of St.Lawrence; NAFO divisions 4RSand 4T), and two time periods (before the collapse, in the mid-1980s, and after it, in the mid 1990s). Our analyses revealed that the ecosystem structure shifted dramatically from one previously dominated by piscivorous groundfish and small-bodied forage species during the mid-1980s to one now dominated only by small-bodied pelagic species during the mid-1990s in both southern and northern Gulf.The species structure in the northern Gulf versus southern Gulf was different, which may explain why these two ecosystems did not recover the same way from the collapse in the early1990s. Productivity declined in the northern Gulf after the collapse but increased in the southern Gulf. The collapse of groundfish stocks resulted in declines in the mean trophic level of the landings in both the northern and the southern Gulf. Even though fishing mortality was then intentionally reduced, this part of the total mortality was taken up by predation.The temporal changes in the internal structure of both ecosystems are reflected in their overall emergent properties.©2009 Elsevier Ltd.

D'AMOURS, O., P. ARCHAMBAULT, C.W. MCKINDSEY, L. ROBICHAUD, 2008. The influence of bivalve aquaculture on ecosystem productivity. World Aquacult., 39(3) : 26-31.

TRIPPEL, E.A, M.J. MORGAN, A. FRÉCHET, C. ROLLET, A. SINCLAIR, C. ANNAND, D. BEANLANDS, L. BROWN, 1997. Changes in age and length at sexual maturity of northwest Atlantic cod, haddock and pollock stocks, 1972-1995. Can. Tech. Rep. Fish. Aquat. Sci., 2157, 120 p .

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En 1993, le ministère des Pêches et des Océans a constitué un Groupe de travail sur la maturité pour la zone atlantique, qu'il a chargé d'établir les tendances à long terme de l'âge et de la longueur à la maturité sexuelle pour plusieurs des principaux stocks de gadidés. Notre rapport présente les résultats obtenues et fait des observations sur leur application possible à l'halieutique et à des questions connexes de conservation. Des baisses notables de l'âge et de la longueur à la maturité sexuelle ont été observées dans la plupart des stocks de gadidés de l'Atlantique nord-ouest depuis le milieu des années 80, et particulièrement depuis 1990. Dans l'ensemble, les stocks les plus septentrionaux atteignaient la maturité à un âge plus avancé et une taille corporelle plus grande que les stocks de sud, mais ces dernières années l'écart s'est resserré. Dans un stock donné, les femelles atteignaient généralement la maturité à un âge plus avancé et une taille corporelle plus grande que les mâles. Nous formulons des recommandations visant à soutenir de nouvelles initiatives qui doivent aider à maintenir la série chronologique sur la maturité dans ces stocks de poissons.