Movements and aggregation areas of adult Atlantic sturgeon (Acipenser oxyrinchus) in the St Lawrence River estuary, Quebec, 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 14.5-23.4degrees C water temperature range. Mean daily distances traveled were 13.7 +/- 20.8 km (n = 77) and mean travel speeds were 1.6 +/- 1.7 km h(-1) (n = 88). Adult sturgeon locations were generally from sites deeper than 10 m at low tide. Management implications of these results are discussed.