Citation. Ross, M. J.; Kleiner, C. F. 1982. Shielded-needle technique for surgically implanting radio-frequency transmitters in fish. Progressive Fish Culturlist 44(1):41-43.   [1485  CC]

Introduction. Surgically implanted radio-frequency transmitters are preferable to external transmitters for experiments on fish in dense aquatic vegetation (Stasko and Pincock 1977). The performance of the implanted transmitter is improved by adding a protruding whip antenna, which results in (1) reducing the size of the transmitter; (2) providing a longer range for a given power output, and (3) requiring less critical tuning. Provision of an outlet for the antenna through the body wall has presented some problems, but Winter et al. (1978) described a technique in which a knitting needle was used to tunnel a cavity under the skin. However, we found this method somewhat difficult to use on fish with abdominal pelvic fins because of difficulty in tunneling past the pelvic girdle without piercing vital organs or the skin. To overcome this problem, we developed a shielded-needle technique to guide an antenna made of 24- or 26-gauge Teflon-coated conductor wire along the intestine under the pelvic girdle (Fig. 1).

Keywords. external transmitters, fish, shield-needle technique, internal transmitters