Movements and aggregation areas of adult Atlantic sturgeon (Acipenser oxyrinchus) in the St Lawrence River estuary, Québec, Canada

In 1998 and 1999, 49 adult St Lawrence River Atlantic sturgeon (Acipenser oxyrinchus) were equipped with ultrasonic transmitters and tracked during the summers of 1998-2000 with the objective of studying movements and identifying aggregation and spawning areas. The 3 years of study led to the localization of six adult aggregation areas, four in freshwater and two in brackish water. Three of the freshwater aggregation areas (Richelieu Rapids, Saint-Antoinede-Tilly and the mouth of the Chaudiere River) were identified as potential spawning areas. The three other aggregation areas (Saint-Charles River estuary, Traverse du Milieu Channel and the northern channel between Sault-au-Cochon and Petite-Riviere-Saint-Francois) were identified as feeding and/or resting areas. Telemetry and gillnetting results suggest that St Lawrence River Atlantic sturgeon spawning occurs between early June and mid-July, within the 14.5-23.4 degree C water temperature range. Mean daily distances traveled were 13.7 plus or minus 20.8 km (n = 77) and mean travel speeds were 1.6 plus or minus 1.7 km h super(-1) (n = 88). Adult sturgeon locations were generally from sites deeper than 10 m at low tide. Management implications of these results are discussed.