Migration and Mortality of Tagged Striped Bass in the Roanoke River and Albemarle Sound, North Carolina

We are examining migration and mortality of striped bass in the Roanoke River and Albemarle Sound, North Carolina, using a combined tagging approach.  Striped bass are economically important and this research will improve stock assessment.  Early in 2011, we tagged 84 striped bass with a sonic tag and a $100-reward internal anchor tag, and over 3,000 striped bass with a PIT tag.  We are identifying movements of sonic-tagged individuals with stationary receivers and evaluating rates of harvest and catch-and-release by returns of internal anchor tags and detections of PIT tags from fishhouses and creel surveys.  Excluding tag mortality (10%), sonic-tagged fish were detected at multiple receivers in the Albemarle Sound and Roanoke River.  Eighty-two percent of the sonic-tagged individuals migrated into the Roanoke River during 2011, with 68% reaching spawning grounds at Weldon, most during April and May.  In 2011, 17% of the sonic-tagged individuals were caught either commercially (n=2) or recreationally (n =12) and 75% of those caught recreationally were released.  Although striped bass behavior was sometimes altered by catch-and-release, all released individuals survived.  Using North Carolina Wildlife Resources Commission creel data, our preliminary population estimate for striped bass spawning in the Roanoke River in 2011 was about 732,000.