Assessment of Striped Bass Spawning Stock in Roanoke River, North Carolina

A total of 4,920 striped bass (Morone saxatilis) were collected from Roanoke River near Weldon, North Carolina, by electrofishing during the spring of 1991 and 1992. Study objectives were to determine sex ratio and age composition of the Albemarle Sound/Roanoke River striped bass spawning stock. Differences in catch per unit effort (CPUE) between years, among year classes, and between sexes were analyzed. Male striped bass represented 83% and 87% of the sample over the 2 years. Nearly all male (99%) and female (91%) striped bass captured were Ages 2 through 4. Ninety-six percent of the fish in 1991 and 89% in 1992 were from the 1988 and 1989 year classes. A greater proportion of striped bass, both male and female, migrated to the spawning grounds at Age 3 than at Age 2 and females did not migrate in equal proportions as males until at least Age 4. Analysis of variance (ANOVA) of log-transformed CPUE data between 1991 and 1992 indicated that catch rates were significantly lower in 1992 for the 1982 through 1988 year classes. Mean CPUE for these year classes decreased by 54% (range: 23%-79%) in 1992. The scarcity of older age classes on the spawning grounds suggests that fishing has affected survival. If the CPUE decline observed between 1991 and 1992 reflected annual mortality, then the mortality rate exceeded that targeted for restored, healthy striped bass populations. We recommend that fishing rates or other sources of mortality be reduced to sustain the recovery of the Albemarle Sound/Roanoke River population.

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