Origine des saumons (Salmo salar) pêchés au Groenland et influence sur la mortalité en mer

Authors: Gauthier-Ouellet, Marika
Advisor: Bernatchez, Louis; King, T. J.
Abstract: Identifying the origin of catches in a mixed-stock fishery, to consider the demographic status of distinct populations, is a major challenge. Here, we identified the North American origin of 2835 salmon collected at the Greenland fishery for seven years spanning an eleven-year period (1995-2006) at three localities using 13 microsatellites. The study included 52 baseline populations representing nine genetically distinct regional groups. Our ability to identify the origin of salmon at the river level was also tested in two regions. The average level of contribution associated with each genetic region ranged from less than 1% for Maine to nearly 40% for Southern Québec. Temporal variation in regional contributions was observed, indicating a decreasing contribution of Southern Québec (-22.0% from 2002 to 2005) and New-Brunswick (-17.4% from 1995 to 2006) and an increasing contribution of Labrador salmon (+14.9% from 2002 to 2006). There was a strong association between the number of multi-sea-winter salmon regionally produced and the estimated regional contribution to Greenland fishery for 2002 (r = 0.79) and 2004 (r =0.92), which could explain these temporal trends. No difference was found between the three Greenland sampling localities, suggesting a random distribution of the different salmon groups along the coast. Multi-sea-winter mortality rate due to Greenland fishery was highly variable among groups, with Ungava and Southern Québec showing the highest values, ranging from 12.10 to 18.08%, for both years tested. Overall, no regional group was clearly overrepresented in landings compared to their respective productivity. Yet, management precautions should still be taken as the fishery strongly selects large females, which could have evolutionary impacts on populations over the long term, such as a decrease in the proportion of multi-sea-winter salmon compared to grilse.
Document Type: Mémoire de maîtrise
Issue Date: 2008
Open Access Date: 13 April 2018
Permalink: http://hdl.handle.net/20.500.11794/20347
Grantor: Université Laval
Collection:Thèses et mémoires

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