7802 - Laserfiche WebLink

Home Browse Search

130 Swimming Against the Current In June 1979 the USFWS and USBR signed a memorandum of understanding (MOU) whereby the USBR agreed to fund a com- prehensive investigation of the endangered Colorado River fishes in the upper basin. The USFWS agreed to obtain the information essen- tial to providing biological opinions on im- pacts of existing and proposed water-develop- ment projects. The primary objective of the USFWS'S effort, named the Colorado River Fish Project (CRFP), was to acquire informa- tion needed to recover endangered fishes while allowing the USBR to operate existing projects as well as to plan and construct pro- posed projects, Initially, the CRFP extended over 965 km of the Colorado and Green rivers and their tribu- taries in Colorado and Utah. Studies focused on identification of spawning requirements, habitat requirements of young and adults, mi- gratory behavior, interspecific competition, predation and food habits, effects of tempera- ture, salinity, and chemicals, development of culture techniques, disease and parasite diag- nostics, and taxonomy (w. H. Miller et at. 1982d), Fieldwork from 1979 to 1981 em- phasized sampling the upper Colorado River from Lake Powell to Rifle, Colorado (Valdez et at. 1982b), and the Green River from its confluence with the Colorado upstream to Split Mountain Gorge (Tyus et at. 1982b), to determine distribution, relative abundance, movements, and habitats of various life stages. The 1979 MOU was amended in 1981 to include an investigation of humpback chubs in the Little Colorado River, Arizona (Kaed- ing and Zimmerman 1983), and to expand field studies in the upper basin to include the Dolores and Gunnison rivers, Colorado-Utah (Valdez et at. 1982a). Additional funds pro- vided by the U.S. Bureau of Land Manage- ment to include White River, Colorado-Utah (w. H. Miller et at. 1982b), and funds from Congress and the U.S. National Park Service (USNPS) supported field research on the Yampa and Green rivers in Dinosaur NM (W H. Mil- ler et at. 1982c). Funding provided through the Windy Gap process was used for a three- year habitat use and radiotelemetry study of Colorado squawfish and humpback chubs on the upper Colorado River, and to investigate use of "nonflow alternatives" (habitat devel- opment, fish passage, and stocking) as means of maintaining and ensuring recovery of the fishes of concern (Archer et at. 1985). Laboratory research for Colorado squaw- fish outlined in the MOU included swimming stamina, bioassays of potentially toxic trace element tolerances, and determinatiofl<<)f pref- erences for temperature and total dissolved solids. In addition, various contracted studies examined physicochemical habitat conditions in the Green and Colorado rivers, culture of rare fishes, diseases, movements of Colorado squawfish in the inlet to Lake Powell, and stomach contents of fishes (W. H. Miller et at. 1982a), The accumulated knowledge of the endan- gered Colorado River fishes was summarized in a 1981 symposium that emphasized srudies conducted after 1975 (W. H. Miller et at. 1982C). The CRFP continued its work after 1982, emphasizing filling gaps in knowledge of ecological requirements of the four rare fishes; for example, delineating necessary stream flows, describing movements (espe- cially those associated with reproduction), and identifying factors limiting recruitment (Archer et at. 1984; Kaeding et al. 1986; Tyus et at. 1987). Other Studies Studies of the ecology of rare fishes were also conducted by biologists from the Colorado Division of Wildlife (CODOW) and the Utah Division of Wildlife Resources (UTDWR) from the early 1980s to the present (e.g., Haynes and Muth 1982; Radant 1982, 1986; Wick et al. 1985). This work, funded through section