Lower Sacramento River Green Sturgeon Telemetry Monitoring

Juvenile Sturgeon
Juvenile green sturgeon (left and right); juvenile white sturgeon (center).
They are approximately 18 months of age.

Currently there is very little known about rearing, migratory behavior, and general emigration patterns of juvenile southern Distinct Population Segment (sDPS) North American green sturgeon (Acipenser medirostris) and white sturgeon (Acipenser transmontanus) within the Lower Sacramento River, Sacramento-San Joaquin Delta, and San Francisco Bay (SFBDE). This data is crucial for improved species management in California’s Central Valley.

To better understand emigration, California Department of Fish and Wildlife is undertaking a collaborative effort with University of California Davis Biotelemetry Laboratory to capture and acoustically tag 100 green sturgeons and 100 white sturgeons per year for three years. CDFW staff conducted sampling by deploying and tending 33-m variable mesh gill nets anchored with 18-kg pyramid weights. Juvenile sturgeon are surgically implanted with Vemco® V9 69 kHz acoustic transmitters and released near the point of capture. An array of Vemco® acoustic receivers deployed throughout the SFBDE collect detection data for acoustically tagged juvenile sturgeons. To date, (January 2018) CDFW and UCD staff tagged 16 juvenile green sturgeon and 11 juvenile white sturgeon over 159 days of sampling effort.

Based on the extremely low catch per unit effort, results suggest recruitment during consecutive critically dry water years may be low. After a normal water year in 2016 and wet water year in 2017 with corresponding higher SFBDE outflows, we hope that juvenile sturgeon recruitment and catch per unit effort will increase in 2017-2018. Telemetry data from all years was compiled and analyzed for differences in water year-type habitat utilization and migratory behavior. The limited telemetry data acquired to date suggest differences in movement patterns between the two sympatric sturgeon species and substantiate previously undocumented migratory behavior in juvenile and sub-adult sDPS green sturgeon.