Gulf Sturgeon Spawning Migration and Habitat in the Choctawhatchee River System, Alabama - Florida
adult, anadromous fish, Atlantic sturgeon, behavior, degradation, eggs, Florida, habitat, migration, spawning, sturgeon, Substrate, telemetry, upstream
Journal or Book Title
Transactions of the American Fisheries Society
Information about spawning migration and spawning habitat is essential to maintainand ultimately restore populations of endangered and threatened species of anadromous fish. Weused ultrasonic and radiotelemetry to monitor the movements of 35 adult Gulf sturgeon Acipenseroxyrinchus desotoi (a subspecies of the Atlantic sturgeon A. oxyrinchus) as they moved betweenChoctawhatchee Bay and the Choctawhatchee River system during the spring of 1996 and 1997.Histological analysis of gonadal biopsies was used to determine the sex and reproductive statusof individuals. Telemetry results and egg sampling were used to identify Gulf sturgeon spawningsites and to examine the roles that sex and reproductive status play in migratory behavior. FertilizedGulf sturgeon eggs were collected in six locations in both the upper Choctawhatchee and Pearivers. Hard bottom substrate, steep banks, and relatively high flows characterized collection sites.Ripe Gulf sturgeon occupied these spawning areas from late March through early May, whichincluded the interval when Gulf sturgeon eggs were collected. For both sexes, ripe fish enteredthe Choctawhatchee River significantly earlier and at a lower water temperature and migratedfurther upstream than did nonripe fish. Males entered the Choctawhatchee River at a lower watertemperature than females. Results from histology and telemetry support the hypothesis that maleGulf sturgeon may spawn annually, whereas females require more than 1 year between spawningevents. Upper river hard bottom areas appear important for the successful spawning of Gulfsturgeon, and care should be taken to protect against habitat loss or degradation of known spawninghabitat.