A comparison of gastrically and surgically implanted telemetry transmitters in shovelnose sturgeon

P>Transmitter retention and the effects gastrically and surgically implanted telemetry transmitters had on condition and mortality of shovelnose sturgeon, Scaphirhynchus platorhynchus (Rafinesque), > 450-mm fork length were examined. Four, 35-day trials were conducted with approximately equal numbers of control fish, fish receiving dummy transmitters gastrically and fish receiving dummy transmitters surgically. Four sturgeon expelled gastrically implanted transmitters during the observation period. Two mortalities occurred among fish receiving gastrically implanted transmitters during the study period and one mortality was recorded for control fish. No mortalities were recorded for fish receiving surgically implanted transmitters. Condition change (Delta K-n) was significantly different between fish receiving surgical implantation (mean Delta K-n +/- SE; -5.17 +/- 0.94), fish receiving gastric implantation (-2.98 +/- 0.72) and control fish (-0.65 +/- 1.09). Surgical transmitter implantation is recommended for telemetry studies on shovelnose sturgeon because of increased transmitter expulsion and occurrence of mortality in fish receiving gastric implantation.