Movements of Atlantic Sturgeon Acipenser oxyrinchus in Relation to an Aggregation Area

Atlantic sturgeon, (Acipenser oxyrinchus), have been historically overfished and are currently proposed to be listed as endangered or threatened under the Endangered Species Act.  With this listing the identification of essential habitat and nursery areas for the conservation of this species will be required for management purposes.  Currently there is an information gap regarding the movements and habitat preferences of the juvenile Atlantic sturgeon migrant stage within the marine environment.  Previous work suggests that juvenile marine migrant Atlantic sturgeon aggregate in large abundances off Rockaway, NY.  This area has been shown through survey and tagging data to be a juvenile marine migrant Atlantic sturgeon hotspot, with abundances 89 times higher than adjacent areas and where individuals may spend as much as 100 days or more aggregated in these small regions. However, in order to determine whether this area is essential habitat and warrants protection, requires fine-scale observation of movements of sturgeon. In May 2010, a grid of 21 VEMCO receivers were deployed within this region and Atlantic sturgeon (n=24) were acoustically tagged to evaluate and monitor the temporal and spatial habitat use within the area.  Preliminary evidence reveled that Atlantic sturgeon left the area post tagging and some fish returned in September (n=2) and early October (n=6).  For the fish returning in October, 6 fish returned within 7 days of each other while 4 of these fish, that were tagged together, also returned to the area within the same day.  This indicates that there may be coherency such as social behavior, may occur during migration, or that common signals are driving migration.  The results from this acoustic array, and from an additional 100 receivers and 300 tags expected to be deployed coast-wide in spring 2011, will be discussed in relation to coast-wide movements and sturgeon conservation.