7177 - Laserfiche WebLink

Home Browse Search

RESULTS AND DISCUSSION General A total of 31 Colorado squawfish were implanted with radio modules in 1980 and 1981. This included 15 implanted in the Green River, 7 in the Yampa River and 9 in the White River. The long distance movement patterns, local movements and habitat preferences of these fish are presented and discussed by year and river system. Long Distance Movement 1980 Program Colorado squawfish were implanted only in the Green River in 1980. Table 1 presents information on the capture, release and major movements of the six radiotelemetered Colorado squawfish studied in 1980. Four Colorado squawfish were followed 3 to 4 months in 1980. These fish displayed two different types of behavior (Tyus et al. 1981). Fish No's 028 and 165 moved upstream in the Green River from the initial release site reaching the upstream limit of movement in late June-early July after traveling about 80 km (Fig. 3). These two fish then moved back downstream past the point of release. Fish No. 028 was last located by airplane in Labyrinth Canyon over 300 km downstream from its release point. Fish No. 165 left the Green River and ascended the White River to a point 56 km above its mouth, then returned to the Green River-White River junction. The remaining Colorado squawfish, No's 060 and 064 (Fig. 4), were relatively stationary with one fish remaining within 5 km of its release point and the other traveling only about 16 km. Despite considerable effort, contact was lost with No's 060 and 064 during July, and movement during this time cannot be completely ruled out. One Colorado squawfish was recaptured from each group exhibiting the two different movement patterns in order to determine maturity, - condition of the fish and effects of carrying the implanted radio trans- mitter. Fish No. 064 (stationary group) was recaptured and dissected August 8, 1980. This fish was an immature male. Fish No. 165 (movement group) was recaptured and dissected September 2. This fish was a female in an advanced state of sexual maturity which may have accounted for the high degree of movement not observed in the immature fish (No. 064). Fish No. 165 after a movement of about 161 km in 5 days may have ex- hibited spawning behavior by orienting to a riffle area in the White River (RK 55.2) on July 16, 1980. An inspection of the viscera of the two recaptured Colorado squaw- fish implanted with radio modules was made in order to compare dif- ferences in fish health to the different movement patterns. In both fish, the modules were effectively walled off from the intestines by adhesions and had to be teased free from this mass for inspection. No evidence of irritation to internal organs was seen in either fish. 6