7982 - Laserfiche WebLink

Home Browse Search

er basin has also 977), but more ,itat is estimated le same number teen introduced 1982b), replace- 1 complete, and -eaches least af- 'ulations of CoI- endemic fishes ro conversion of impoundments, habitat by cold 'on of migration ~ph et a!. 1977; X'ick 1982.; Tyus )acts, including .1shes, small but md downstream i, have also been , 1978b, 1989a), to document or ,isoning of the es implicated in ~ Holden, chap. [4). There is no radicated in the ~n it was treated ih were killed as h of the Yampa of the treated i tailwaters, and tory routes for _ make the issue ::deral and state policy direction ::over remaining ~deral agencieS, with the USFWS velopment. proj- to learn more; ~cies. Provisions xention on man- . 1 t N t CA , ';'--t<"~ .~. f f Fig. 19-5. Map of the Colorado River basin, western United States, showing relative concentrations of modifications and their impacts on the system. agementoptions for these species for the first time. As a result, species-specific recovery plans (USFWS 1978b, 1989a) and regional re- covery implementation programs (USFWS 1987a) were drafted by cooperating federal, state, and other agencies and individuals. Under the ESA, management options must, by law, place the highest priority on removing threats to extinction. Hence, downlisting species from endangered to threatened (par- The Colorado Squawfish 391 NM 9 a.o l~O km Impoundment Downstream Impacts Dam or Obstruction IBI ~""""'I .... .,/ rial recovery) or delisting (full recovery) are primary goals. Only after these goals are met should other options be considered. Frankel (1983) noted three elements to con- servation: (1) the target (in this case the Col- orado squawfish), (2.) "time scale of concern" (Frankel 1984), and (3) management.Man- agement affects the distribution, abundance, and numerical relations of and between species. Whereas "preservation" is often