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. ~ ~~ ~'~ ~~ ~ ~ low flows, the fish used slow an fast runs almost exclusively. The change in habitat use without a correspond ng change in relative habitat availability indicates that other factors al o influence habitat selection. These factors could include changes in quasi of physical habitat features such as diversity, depth, dissolved ox gen, etc., or changes in biotic interactions. Osmundson et al. (1995) inter eted the squawfish behavioral changes as reflective of suboptimal cond tions; the behavioral changes demonstrate the ability of the species to mo 'fy their habitat use patterns to temporarily cope with adverse conditions and do not demonstrate habitat preferences under optimum conditions. Osmunds n et al. (1995), therefore, based their flow recommendations on the habit t-selection behavior of adult squawfish observed during the higher somewhat ors natur~l_flow conditions. Under adjusted baseline conditions for the 1975-1993 period of record, summer flows have fallen below recommended levels in 53 months out of 57 months. Winter (November-March): Osmundson et al. (1995) reported that flows during the winter are usually moderate because no water is diverted for irrigation and because additional water is released through upstream dams to increase reservoir storage capacity in anticipation of spring runoff. The relative availability of slow runs and riffles during the winter was very similar to their availability during summer. As in the summer, backwaters, eddies, and pools were the preferred types of habitat in the winter. However, whereas eddies were most preferred in summer, pools were most preferred in winter. Adult squawfish used fewer habitat types overall during winter than during summer. Although fast runs and riffles were used during the summer, they were not used during the winter. The colder water temperatures in winter which cause lower metabolic rates may account for the avoidance of high velocity sites. Absolute area of pools increases as flows decrease and slow runs lose velocity. Because Osmundson et al. (1995) did not sample low flows in the winter, they could not determine o° a~'.wint s. herefore, they recommended winter flows at the pr~,,~`'moderate flow level which maximized weighted area of preferred habitats. ~"`~,J~' Under adjusted baseline conditions for the 1975-1993 period of record, winter . ,~~ ' flows have fallen below recommended levels in 34 months out of 95 months. ~~ ~ ~ Spring (April-July): Osmundson and Kaeding (1989) reported that squawfish use s of low velocity habitats such as backwaters and flooded gravel pits is greatest during the spring runoff. It is believed that squawfish use these habitats during the runoff to escape the high velocity, low temperature flows of the main channel. Because backwaters, flooded gravel pits, and other low velocity habitats are considerably warmer than the main channel during the runoff, these habitats allow squawfish to extend their growing season substantially. The earlier warming of these habitats may also be important in enabling squawfish to reach spawning condition by the time flow and temperature in the main channel are optimum for spawning. Osmundson et al. (1995) reported that the numbers of backwaters and flooded gravel pits increases with increasing spring flows. (Although the number of backwaters eventually decreases as increasing flows co backwaters to sidechannels, the number of other low velocity habitat ikely i creases as increasing flows inundate additional bottomlands.) The a in the magnitude, duration, and frequency of high spring flows, then decreases the quantity-and the duration and frequency of availability f important low velocity, higher