Movements of triploid grass carp in the Cooper River, South Carolina

The movements of triploid grass carp (Ctenopharyngodon idella Valenciennes) were monitored in a coastal river flowing out of the Santee Cooper reservoirs, South Carolina. Twenty-two adult triploid grass carp (90 cm to 110 cm total length) were tagged during 1998 and 1999 with sonic and radio transmitters, released into the Cooper River, South Carolina, and tracked through May 2000. A total of 122 observations were made, of which, approximately 70% were near stands of hydrilla (Hydrilla verticillata (L.f.) Royle). Approximately 98% of the fish locations were within 20 river km of the release site. The average maximum movement was 14.4 km while the longest was 44 kin. We detected no movement into brackish water nor extensive migrations; however, we urge caution where escapement of grass carp to coastal river is possible, and stocking should be evaluated on a case by case basis.