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The progression from egg. to yearling is another segment of this fish's life history that is very finely balanced between adequate re- cruitment to maintain a viable population and slow decline to extinction. Indications are that larvae drift, probably passively for a time, downstream into more moderate reaches which offer sanctuaries in the form of backwaters. This drift appears to be up to 100 mi distant. These larvae and fry have exhibited such a strong attraction to backwaters that one can only conclude that backwaters are very critical to these fish's survival. Observations suggest that those backwaters that are more permanent throughout the hydraulic cycle and are least impacted by high and low flows are the most attractive to young squawfish. Those that are dewatered or flushed at high or low flows generally supported fewer young squawfish. There is a danger in conducting off-channel gravel pits or other constricted quite-water areas with backwaters. These were not the beneficial habitats one might conclude upon cursory examination because of the extensive exotic, particularly Centrarchid, populations they harbored. They, therefore, presented a very alien ecological environment to the younger squawfish and, in fact, may have negatively impacted main-channel populations by providing a source of recruitment of those exotic species to the river. During late summer through the fall months, YOY squawfish preferred backwater areas of zero velocity, less than 1.5 ft in depth over a silt substrate. Where these habitats were prevelent, substantial numbers of YOY squawfish were collected. Where they were lacking, few YOY were found. Similar selective behavior was observed during the early spring, prior to runoff. During and after heavy runoff few young fish were captured in significant numbers. It is not known whether their behavior changed drastically 'in preference for other, less effectively sampled habitats or if these fish experienced very high mortalities during runoff. Juvenile squawfish (60mm-400mm TL) exhibited habitat preferences similar to the YOY fish but appeared to be more mobil and adaptable to conditions away from the very sheltered environment provided by backwaters. Collection Ad~e,.,~n~trated a preference for negligible velocity and silty ~ substrates,~~'~iut"the range of conditions where juveniles were caught extended into the higher velocities and courser substrates than for YOY. They clearly exhibited a preference for greater depths, averaging betweea 1.2 to 3.3 ft. Depth preferences were higher for the Colorado than the Green. This probably reflected a greater availability of deeper waters in the Colorado rather than a difference between populations. We interpret juvenile habitat preference as representing an intermediate phase in the shift from the backwater requirements of YOY to the deeper main-channel eddy and shoreline habitats preferred by the adult squawfish. Adult squawfish sought out habitats of moderate depths, between 3 and 6 ft, with velocities of less than 1.0 ft/sec. During the runoff period they appeared to select areas away from the main channel that provided velocities below those observed during other times of the year. Generally, squawfish larger than 400 mm preferred habitats adjacent to the main river channel that offered some depth, but not necessarily the greatest depths available in the area, and some protection from higher