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Flaming Gorge fluctuations may alter movement of rare fish By RIchard A. Valdez Senior Fishery Biologist BIOiWEST. Inc. Logan, Utah Hourly fluctuations in water flows of the Green River below Flaming Gorge Dam appear to affect adult Colorado squawfish and razorback sucker as far as 120 miles downstream. Variable amounts of water are released by , Flaming Gorge throughout the day to meet consumer demands for elecoical power. Local movement of adult Colorado squawfish and razorback sucker in this area was found to be greater than in regions further downstream not affected by fluctuating water flows. These differences were found during winter in the Green River from the Yampa River confluence 55 miles downstream to the Bonanza Bridge. The fishes' movement was apparently in response to the changes in water level and velocity. This discovery came during a two-year study of the winter habitat and movement of these two species in the Green River in Utah and Colorado. BIO/WEST Inc., an environmental consulting fmn, conducted the study through a contract with the Bureau of Reclamation. Scientists are not sure how these changes affect the fish. However, they speculate that the increased activity level could affect the fishes' reproductive capability, growth and general health. In conducting the study, researchers radio- tagged 10 adult Colorado squawfish (Ptychocheilus lucius) and 10 adult razorback sucker (Xyrauchen texanus) in October of 1986 and 1987. They tracked the fish from December through the following March each of the two years. During 24-hour observation periods, the fish used from two to eight "micro-habitats," very specific locations where they remained for several hours and moved very little. The fish sometimes returned to the same micro-habitat several times. Average movement of Colorado squawfish in ice-free conditions was 76 feet per hour. Their movement increased to 96 feet per hour under ice, indicating use of ice as cover while foraging for small food fish. Average movement of razorback sucker in ice-free conditions was 102 feet per hour and did not change under ice. The fish changed micro-habitats more frequently in conditions of fluctuating flows. The amount oflocal movement by Colorado squawfish in ice-free conditions increased by 190 percent to 220 feet per hour when the water level increased or decreased by more than 2 inches per hour. Movement of rawrback sucker increased by 39 percent to 142 feet per hour. This increased movement apparently was in response to excessive velocity when water flows increased or to drops in water depth when the flows decreased. Although the fish showed considerable local movement, they did not move long distances during the winter. Squawfish moved a maximum of 25.9 miles downstream; razorback moved up to \0.5 miles downstream. But the majority remained within a three-mile stretch of river. TIris is significantly less than at other times of the year, especially during pre-spawning migration in late June and July, when Colorado squawfish have been known to travel 250 miles. During the winter, adult fish used mid-channel, low-velocity habitats. Few were found spending the winter in backwaters. The U.S. Fish and Wildlife Service will use the results of this and other studies to make recommendations on operating Flaming Gorge to improve habitat conditions for the endangered fish. Media relations, publications highlight 1990 public information plan By Connie Young Information and Education Coordinator Endangered Fish Recovery Program Colorado Division of Wildl~e. Denver Informing the public about the endangered fish of the Upper Colorado River Basin is the task at hand for the II-member Wormation and Education Subcommittee of the Recovery Program. The group has developed a fIVe-year plan to reach nearly 20 different target audiences ranging from school children to research biologists. In the 1990 fiscal year the group plans to: . Produce two issues of the newsletter. . Add information on the endangered fish to the Colorado fishing regulations. . Produce a slide show and full-color poster. . Deliver presentations to key groups. . Develop a media relations plan and media kit. . Produce signs for use along the Colorado River and its oibutaries in Colorado and Utah. . Conduct a survey to detennine the base line level of public awareness of the fish. For a copy of the plan, contact Connie Young, Colorado Division of Wildlife, 6060 Broadway, Denver, Colo. 80216 (303) 291-7322. 9