7166 - Laserfiche WebLink

Home Browse Search

relocated in the lower 20 mi (32 km) of Yampa Canyon (Table 18). By late July, all the radiotagged fish had left the lower Yampa Canyon and when relocated, were generally found at the same area of initial capture. Found in association with these fish was one Colorado squawfish radiotagged in the lower Green River, RM 248 (km 397), near Ouray, Utah, which also returned to its initial location in late July. Fish No. 273 (Table 18) implanted at Echo Park in the Green River, moved upstream in early July. This fish was lost in Ladore Canyon on 11 July. Although an attempt was made to capture other Colorado squawfish in Ladore Canyon in early July, none were captured. Radiotelemetry of Colorado squawfish in the Green River in 1980 suggested that such long distance movement at that time of year was associated with spawning (Tyus et al. 1981). Although objectives of the Yampa study did not permit disturbance of the radiotagged squawfish, extensive collecting with floating trammel nets was conducted near them. Collections made from 1 July to 9 July, 1981 produced 34 Colorado squawfish in spawning condition. These fish were either ripe males or spent females and catch reflected a very high catch per effort of ripe Colorado squawfish from short pool-riffle-pool habitat sections in the lower Yampa Canyon. Eight radiotagged Colorado squawfish migrated to the lower Yampa River during June and July (Figure 13). Distances traveled during spawning migration were calculated for those fish that returned to the initial point of capture and remained at that location. One of these fish (No. 1) moved past the initial capture point and relocated 54 mi (93 km) upstream. Contact with the Fish No. 2 was lost on the spawning grounds. however, since the fish was tagged in October 1979 at RM 55 (km 88) by Colorado DOW and recaptured two years later at this same location, the assumption is made that this fish returned there (with an inoperable radio tag). The remaining six fish (No's 3-8, Figure 13) exhibited a spawning migration that accounted for 96% of the total movement during the study period. Data from conventional tag recaptures substantiate the movement exhibited by the radiotelemetered fish. Four Colorado squawfish were recaptured on the spawning grounds. Two of these (Table 19) were tagged on the upper Yampa in August 1978 and 1980, and the other was tagged in the upper Green in May 1981. A total of 64 adult Colroado squawfish were tagged with Carlin dangler tags in the Yampa River and 15 were tagged in the Green River (in DNM) during 1981. Seven of these fish were recaptured. In addition, five adults, initially tagged by other investigators from 1978 to 1980, were also recaptured. Only one fish (No. 0219) was recaptured in the Green River (DNM); however, 11 were recaptured in the Yampa River (Table 20). No population estimates can be calculated from the tag/recapture data because of the small numbers of fish captured and the bias R inherent in tag/recapture calculations for a migrating species. 56