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1 ' middle, and late arrival dates. Results from these simulations su ested that red shiner redation gg P ' was a significant source of mortality for young squawfish: squawfish survival to the end of the ' growing season ranged from 8 to 25% (Figure 7). Survival was about one third lower with the cool thermal regime than with warmer temperatures, because the larvae grew more slowly at ' cooler temperatures and they remained vulnerable to predation longer. In all cases the number of ' surviving larvae declined rapidly, with only 20-30% of larvae surviving more than a month (Figure 8). ' Survival was relativel low for cohorts arrivin in the backwaters eazl or late in the Y g Y ' season, and was highest for those with intermediate arrival dates (Figure 7). Larvae arriving ' eazly experienced rapid growth because temperatures were warm and increasing (Figure 5), but the shiners were lazge during this time, so survival was still relatively low. Larvae that arrived in ' mid-season encountered the best conditions for survival; predators were relatively small and the ' larvae experienced a full month of relatively warm water temperatures which allowed rapid growth to sizes that were not vulnerable to predation. By the time late-spawned cohorts arrived, ' tem eratures were be innin to decline and redators had rown to relativel laz a size a ain, so P g g P g Y g g ' these late-arriving larvae experienced high mortality rates. Their survival was about equal to ' eazly-arriving cohorts, even though they were exposed to predation for half as much time. Squawfish size at the end of the growing season was strongly affected by arrival time ' (Figure 9). Survivors from cohorts that arrived eazly were almost twice the size of those from ' late-arriving cohorts, because they had much more time to grow. Larvae that arrived in June became invulnerable to red shiner predation half-way through the season, while survivors from 19