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,i <br />migration and long-term movement patterns for exploiting changing habitats and <br />environmental conditions of the late Cenozoic - developing adaptations that <br />enabled the fish to compete and survive until the coming of civilized man <br />(G.Smith 1981, Tyus 1986). As a result, adult, juvenile, and young Colorado <br />• squawfish have developed different life history attributes for survival, and <br />adapted to utilize virtually all habitats represented in the mainstream river, <br />as indicated by the distribution of life stages. <br />s The adaptations of this fish must be used as the basis for management for- <br />s recovery. As an example, the USFWS has used different life stagLes in designing <br />{Wp~ uid~ Qw~ Mz.~~G~etir <br />I "sensitive areas" to protective measures a€~s (see <br />~'- L~ w ~ L <br />~ ~.g~-`~w management section this paper, also Ascher et al. 1986, USFWS 1987). Major <br />Z <br />('~~ ~~'` life history stages and events are discussed separately in following sections, <br />,` where reference is made to them in an attempt to develop a holistic approach <br />to species management. Particular emphasis is placed on distribution and <br />abundance, because management objectives, and population responses to any <br />management tool depends on population response. <br />LIFE CYCLE <br />Adults <br />C <br />olorado squawfish are capable of long-life and large size. Since the <br />adult fish was the largest native predaceous fish in the Colorado River, <br />survival to a large size would insure low adult mortality - important species <br />attributes, presumably with selective advantage. Thus, a long growth period <br />S <br />