Effects of surgically implanted dummy ultrasonic transmitters on growth, survival and transmitter retention of bighead carp Hypophthalmichthys nobilis

The effects of surgically implanted dummy ultrasonic transmitters on growth, survival and transmitter retention of bighead carp Hypophthalmichthys nobilis were investigated from October to November 2010. Before the surgery, 162 bighead carps were divided into three groups: 1) control group: handling but no tagging; 2) sham group: surgical procedure without implantation of dummy ultrasonic transmitter; 3) surgery group: surgical implantation of dummy ultrasonic transmitters. Growth, survival, incision healing, suture loss and transmitter retention of bighead carp were recorded and analyzed respectively at 14, 28 and 56 days after surgery. The results showed that surgical implantation of dummy ultrasonic transmitters had a significantly negative influence on growth of bighead carp, however, the negative influence was negligible 28 days after surgery. No fish died during the experimental period. All incisions had completely healed 56 days after surgery, but sutures remained in 21 fish, and the suture loss rate was 70.8 %. All fish with suture retention had suffered light infection over the incision sites. No dummy ultrasonic transmitters were expelled 56 days after the surgery. Except for three transmitters, all the remaining transmitters were completely encapsulated in a fibrous capsule and adhered to the body wall, intestinal tract or viscera 56 days after surgery. The above results suggested that telemetry research could be conducted on bighead carp within 56 days after surgical implantation of ultrasonic transmitters.