7402 - Laserfiche WebLink

Home Browse Search

closed using 4-5 sutures of 3/0 or 4/0 dissolving catgut or permanent surgical thread and curved needles held by a hemostat clamp. All surgical instruments and the wax-coated transmitter would be soaked in a disinfecting iodine solution and rinsed prior to surgery. The incision site on the fish was also cleansed with disinfectant solution and rinsed prior to surgery. During the operation, an assistant would repeatedly pour water over the fish's gills and upper body to maintain ventilation and prevent drying. The assistant used either water dosed with MS-222 from the tub or fresh river water for this process. The fish's status during surgery was monitored using the fish's gilling activity. Reduced gilling activity signified an increasing risk of death to the fish. Fresh river water was used primarily for ventilation during surgery until the fish began recovering from the effect of MS-222. This was noted by increasing body movements that might disturb the surgical process. Anesthetic-dosed water would be used periodically throughout the surgery to keep the fish calm. Upon completion of surgery, the fish was placed in an elongate, mesh bag and placed in the river to recover from anesthesia. After 30-60 minutes, the fish would be removed from the bag, the surgical area checked for adequate closure, and the fish allowed to swim away under its own power. The fish was released when it was capable of swimming strongly enough to elude recapture by hand. With the presence of radio-tagged northern pike in various river reaches, subsequent sampling trips included searching for these fish via radio tracking. Using an ATS receiver and 2.5 m whip antenna to monitor the various frequencies employed, a given river reach would be searched for signals emitted by northern pike suspected of being present within the reach. Upon detection of a specific signal, continued approach toward the location would be made as quietly as possible to avoid disturbing th~ fish. Using the ATS receiver with a Smith Root directional antenna tuned to the 30-3~ MHz frequency range, the location of the signal would be pinpointed by triangulation from shore to determine the habitat type occupied by the fish. Thereafter, the fish would be monitored for 15-30 minutes to determine its level of activity. This would be classified as stationary, active within a specific habitat, or progressive movement upstream or downstream. During this time, the presence and location of adjacent habitat types, cover, and aquatic 6 ~ ~ ~