Laserfiche WebLink
<br />Pools inside and outside the canyon tended to hold large concentrations of <br />fish which were readily observable from above. <br />DISCUSSION <br />Possible reasons that Colorado Squawfish are attracted to the Little <br />Snake River might include a preference for warmer temperatures and increased <br />feeding opportunities. Colorado squawfish are known to use warmer backwater <br />and flooded gulches on the Yampa River during spring run-off (Wick et al. <br />1983). Warmer water temperatures and feeding is important in conditioning <br />fish for migration and spawning (McKeown 1984). Backwater habitat is not as <br />abundant in the Lily Park area of the Yampa River as it is in upper portions <br />of the Yampa (Wick et al. 1986). The Little Snake River could provide warm <br />water habitat to squawfish within it or in the Yampa River below the <br />confluence. Reproduction of native fishes in the Little Snake River is <br />occurring, thus providing an important spawning area for these species and <br />possibly a food source for squawfish. Temperature variations in habitats used <br />by Colorado squawfish could influence the timing of spawning migrations and <br />spawning (Wick et al. 1983). Colorado squawfish using the warmer waters of <br />the Little Snake River might undergo an earlier spawning migration than fish <br />residing solely within the Yampa River. This variation could result in <br />prolonged use of the spawning area in Yampa Canyon due to the arrival of <br />squawfish at different times. If spawning habitat is in short supply this <br />could maximize its utilization because of the lengthened spawning period. <br />Colorado squawfish larvae usually hatch after most sucker and roundtail <br />chub larvae have hatched. Larval collections indicated that suckers had just <br />hatched and roundtail chub had probably not completed spawning. Based on size <br />and development, flannelmouth sucker spawned prior to bluehead sucker and it <br />appeared that roundtail chub larvae were just beginning to hatch. Since <br />Colorado squawfish spawn later than Gila species, our larval sampling <br />indicated that adult Colorado squawfish probably left the Little Snake River <br />prior to spawning. Migration of the radiotagged Colorado squawfish from the <br />Little Snake River to the Yampa River spawning area indicates that this fish <br />probably spawned in Yampa Canyon. However, spawning of Colorado squawfish can <br />not be discounted completely since we only sampled larvae on one date. <br />Intensive larval sampling over an extended time period is recommended. <br />Flows on the Little Snake River declined rapidly in June, from over 2000 <br />ft'/s in early June to below 400 ft'/s during late June larval sampling. The <br />two radiotagged Colorado squawfish left the Little Snake River in mid to late <br />June, prior to June 26, possibly in response to decreasing flows. In July, <br />flows declined to below 100 ft' /s by the 10th and below 10 ft%s by the 20th. <br />Presence of humpback chub in canyon sections of the lower Little Snake <br />Rivet appears to be restricted to the run-off period similar to the period of <br />use by Colorado squawfish. It is possible that humpback chub spawn within the <br />Little SnE'e River since two of the seven humpback chub collected were <br />tuberculated; however, larval collections will need to be made to verify <br />spawning success. Humpback chub that move into the Little Snake River during <br />the high water period might be attracted to the canyon area because of the <br />relatively deep, turbulent eddys which are habitats typically associated with <br />the species (Valdez et al. 1982). Although humpback chub are associated with <br />high turbulent flows, they are often collected in low velocity waters nearby <br />(Valdez et al. 1982). When flows decline humpback chub apparently leave the <br />7