Scaphirhynchus Conference: Alabama, Pallid, and Shovelnose Sturgeon

St. Louis, Missouri, 11-13 January 2005

39.  POST-STOCKING MOVEMENTS OF JUVENILE PALLID STURGEON IN THE MISSOURI RIVER BELOW FORT RANDALL DAM, SOUTH DAKOTA

George Jordan*, U.S. Fish and Wildlife Service, 2900 4th Avenue North, Room 301, Billings, Montana, 59101-1228; Phone 406-247-7365; FAX 406-247-7364; george_jordan@fws.gov

Greg Wanner, Wayne Stancill, and Robert Klumb, U.S. Fish and Wildlife Service, Great Plains Fish and Wildlife Management Assistance Office, 420 South Garfield Avenue, Suite 400, Pierre, South Dakota; Phone 605-224-8693; FAX 605-224-9974; greg_wanner@fws.gov, wayne_stancill@fws.gov, Robert_klumb@fws.gov.

Ultrasonic telemetry was used to track seasonal and diel movements of age-3 hatchery-reared juvenile pallid sturgeon Scaphirhynchus albus stocked in the Missouri River below Fort Randall Dam, South Dakota during 2000 to 2002.  The riverine section of the Missouri River and the downstream reservoir, Lewis and Clark Lake, were extensively sampled at approximately two week intervals to relocate as many fish as possible from spring through fall.  Thirteen individual fish were intensively followed for 24 hours (total trackings = 21) to assess diel movements.  A total of 229 relocations were observed from 22 tagged fish; 19 fish were relocated at least once with 16 fish found multiple times.  In 2000, fish were found only upstream of the stocking site, whereas; in 2001 and 2002 the entire riverine portion of the Missouri River was used.  In all years, no fish were relocated in the reservoir.  Mean (± 2 SE) homerange size, defined as the distance (km) between the furthest upstream and downstream locations, was significantly smaller in 2000 (8.3 ± 5.8) compared to 2001 (29.3 ± 8.8) and 2002 (28.9 ± 15.0).  Intensive tracking of individual fish found no significant difference in daily movements (km/d) among years and diel periods (i.e. dawn, daytime, dusk, night); however, fish were significantly more active in fall compared to spring and summer.  Our three year study indicates that movements of juvenile pallid sturgeon based on shorter studies (i.e. < 1 year) should be interpreted cautiously as hatchery-reared fish may not have acclimated to the Missouri River environment until the second year after stocking.