Laserfiche WebLink
<br />. <br /> <br />. <br /> <br />A better understanding of the fish community and life stages present in the lower <br />Duchesne River makes it possible to better assess the role this tributary plays in the life history <br />of endangered fishes as well as the entire fish community of the Upper Colorado River Basin. <br />Successful recovery of all four of the endangered fishes in the Upper Colorado River Basin will <br />depend on the maintenance and expansion of present endangered fish populations, and in some <br />cases the establishment of new populations (Tyus and Saunders 2001). Defmitive evidence of <br />spawning of Colorado pikeminnow or razorback sucker (without positive identification of <br />suspected larval razorback sucker) in the Duchesne River was not obtained over the course of <br />this study, from 1997 through 1999. This information suggests endangered fish (larval razorback <br />sucker and young-of-the-year Colorado pikeminnow) utilizing nursery habitats near the <br />confluence (within 3 miles) moved into the Duchesne River from the mainstem Green River. <br />However, the collection of a suspected larval razorback sucker on 27 May 1998 1.6 miles <br />upstream from the confluence still leaves the question of razorback sucker spawning in the <br />Duchesne River unanswered. The larval sucker (razorback or bluehead) collected this distance <br />from the confluence with the Green River was likely produced in the Duchesne River. <br />Relative abundance of juvenile native species remained stable for the sample period with the <br />exception of speckled dace, which indicated a much higher relative abundance during 1999 than <br />the preceding two years. During 1998, the duration of high flow was the longest and sustained <br />summer base flow was the highest of all three years of the study. <br /> <br />. <br /> <br />. <br /> <br />. <br /> <br />. <br /> <br />. <br /> <br />. <br /> <br />. <br /> <br />. <br /> <br />9 <br /> <br />. <br />