Movements and Habitats of Shortnose Sturgeon, Acipenser brevirostrum in the Savannah River

Telemetry studies were conducted to determine seasonal movements and habitat areas of adult and juvenile shortnose sturgeon (Acipenser brevirostrum) in the Savannah River. Thirty-two adults (19 prespawn and 13 postspawn) and six cultured juveniles were equipped with transmitters between April 1985 and March 1987. Upriver spawning migrations occurred from mid-February to mid-March when river temperatures ranged from 9 C to 12 C. Downstream migrations began in mid-March with all adult shortnosed sturgeon leaving the freshwater reaches by early May. Migration rates were as high as 33 km per day. Based on our observations, two probable spawning sites were identified: rkm 179-190 and rkm 275-278. These areas were characterized by submerged timber, scoured sand, and a clay and gravel substrate. Depths ranged from 6-9 m and bottom velocities averaged 82 cm/sec. The freshwater/saltwater boundary region of the river was utilized by adult and juvenile sturgeon during both fall and winter, and preliminary data suggest that this area may serve as an important feeding ground for sturgeon. A probable nursery area for juvenile shortnose and Atlantic sturgeon was identified, approximately 2-5 km downriver of the freshwater/saltwater boundary region. This area was characterized by sandy-mud and clay-mud bottom at a depth of 10-14 m.