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Bibliography of the Maurice Lamontagne Institute

Simon-Pierre DESPATIE

SAVENKOFF, C., M. CASTONGUAY, A.F. VÉZINA, S.-P. DESPATIE, D. CHABOT, L. MORISSETTE, M.O. HAMMILL, 2004. Inverse modelling of trophic flows through an entire ecosystem: the northern Gulf of St. Lawrence in the mid-1980s. Can. J. Fish. Aquat. Sci., 61: 2194-2214 .

Mass-balance models using inverse methodology have been constructed for the northern Gulf of St. Lawrence ecosystem in the mid-1980s, before the groundfish collapse. The results highlight the effects of the major mortality sources (fishing, predation, and other sources of mortality) on the fish and invertebrate communities. Main predators of fish were large cod (Gadus morhua followed by redfish (Sebastesspp.), capelin (Mallotus villosus), and fisheries. Large cod were the most important predator of small cod, with cannibalism accounting for at least 44 % of the mortality of small cod. The main predators of large cod were harp (Phoca groenlandica) and grey (Halichoerus grypus) seals. However, predation represented only 2 % of total mortality on large cod. Mortality other than predation dominated the mortality processes at 52 % of the total, while the fishery represented 46 %. Tests were performed to identify possible sources of this unexplained mortality. The only way to significantly reduce unexplained mortality on large cod in the model was to increase landings of large cod above those reported. This suggests that fishing mortality was substantially underestimated in the mid-1980s, just before the demise of a cod stock that historically was the second largest in the northwest Atlantic.©2004 NRC Canada

SAVENKOFF, C., H. BOURDAGES, D.P. SWAIN, S.-P. DESPATIE, J.M. HANSON, R. MÉTHOT, L. MORISSETTE, M.O. HAMMILL, 2004. Input data and parameter estimates for ecosystem models of the southern Gulf of St. Lawrence (mid-1980s and 1990s). Can. Tech. Rep. Fish. Aquat. Sci., 2529, 105 p .

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In the present study, we use Ecopath and inverse methods to reconstruct trophic flows through the whole northern Gulf of St. Lawrence ecosystem (NAFO zones 4RS) for the mid-1990s period, prior to the groundfish stock collapse. This was a period of relatively constant biomass for the major species. The whole-system model of the northern Gulf of St. Lawrence is divided into 32 functional groups or compartments from phytoplankton and detritus to marine mammals and seabirds, including harvested species of pelagic, demersal, and benthic domains. We present here details of the input data (biomass, production, consumption, export, and diet composition) for each compartment used for modelling. the successful development of ecosystem models proposed by the Comparative Dynamics of Exploited Ecosystems in the Northwest Atlantic (CDEENA) program will provide powerful new tools to evaluate the impact of human and environmental factors on a variety of Atlantic shelf ecosystems.

MORISSETTE, L., S.-P. DESPATIE, C. SAVENKOFF, M.O. HAMMIL, H. BOURDAGES, D. CHABOT, 2003. Data gathering and input parameters to construct ecosystem models for the nothern Gulf of St. Lawrence (mid-1980s). Can. Tech. Rep. Fish. Aquat. Sci., 2497, 94 p .

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In the present study, we use Ecopath and inverse methods to reconstruct trophic flows through the whole northern Gulf of St. Lawrence ecosystem (NAFO zones 4RS) for the middle 1980s period, prior to the groundfish stock collapses. This was a period of relatively constant biomass for the major species. The whole-system model of the northern Gulf of St. Lawrence is divided into 32 functional groups or compartments from phytoplankton and detritus to marine mammals and seabirds, including harvested species of pelagic, demersal, and benthic domains. We present here details of the input data (biomass, production, consumption, export and diet composition) for each compartment used for modelling. The successful development of Northwest Atlantic (CDEENA) program will provide powerful new tools to evaluate the impact of human and environmental factors on a variety of Atlantic shelf ecosystems.

DESPATIE, S.-P., M. CASTONGUAY, D. CHABOT, C. AUDET, 2001. Final thermal preferendum of Atlantic cod : effect of food ration. Trans. Am. Fish. Soc., 130: 263-275 .