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4 <br />marked fish. All fish captured during this period were measured to the <br />nearest millimeter (mm) total length (TL), weighed to the nearest gram <br />(g), marked with a numbered Carlin dangler tag, and released. The 12 <br />fish captured-in March and April were anesthesized with a solution of <br />unbuffered MS222, and surgically instrumented with radiotransmitters. <br />The surgical procedure used was similar to the one discussed in Bidgood <br />(1980) and used by Tyus et al. (1981). Lateral incisions, approximately <br />1.5 centimeters (cm) in length, were made anterior, and dorsal to the <br />insertion of the pelvic fins and closed with 3 to 4 individual sutures. <br />The suture material used was non-absorbable, black monofilament nylon <br />attached to an FS-1 cutting needle. Following surgery each implanted <br />fish was also marked beneath the dorsal fin with a numbered Carlin <br />dangler tag. The fish were then held in a flow through-live car until <br />they had recovered from the anesthetic and then released. <br />The transmitters were approximately 4.3 cm in length, 1.8 cm in <br />diameter and weighed 11.8 to 12.3 g in the air. The operating frequency <br />was in the 30 MHz band. The transmitters were powered with Lithium <br />cells and had an expected life of 270 days. Eleven of the transmitters <br />were temperature sensitive. Temperature data were transmitted as a <br />function of transmitter pulse frequency. Calibration points of <br />temperature, 0 to 40°C, and transmitter pulse frequency were used to <br />derive regression equations for temperature versus pulse frequency for <br />each unit. The pulse frequency data collected in the field were then <br />used in the equations to obtain temperature. The high, low and mean <br />temperatures of the fish and water temperature of their habitat were <br />plotted for each fish.