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are potentially limiting species in decline; e.g., a high number of an endangered species in one restricted location may not justify its delisting. Based on professional interpretation of the-best available data, the following flow and non-flow related measures are considered important for recovery of listed Colorado River fishes in the Green River basin. These are presented by time of year and species. Spring (March 21-June 21) Colorado squawfish The presence of adult Colorado squawfish in inundated shorelines and lowlands during spring runoff suggests that such behavior, and associated feeding, may offset the large energy expenditure required for migration and spawning. Thus, natural flooding of lowlands in the spring and the consequent increased availability of food and habitat is viewed as important toward physiological readiness of adult Colorado squawfish. Migration signals the onset of the reproductive cycle in Colorado squawfish, and we consider migration cues (e.g., high. spring flows, increasing river temperatures, possible chemical inputs from flooded land) important to the maintenance of successful reproduction. Migration routes must be protected and barriers discouraged. The duration, magnitude, and timing of spring runoff also affects preparation of substrate for spawning, and formation of eddy and pool habitats used by staging fish. High spring flows mobilize and deliver nutrients and sediments downstream, and create nursery areas. Humpback chub The availability of rocky, canyon-bound habitat used by humpback chub may be adversely affected by the present alteration of spring runoff in the Green River. Spawning of humpback chub occurs shortly after highest spring discharge at river temperatures of about 20°C in the Yampa River, and presumably in Gray Canyon area of the Green River. Reduced spring runoff may aid growth of the introduced salt cedar, Tamarix, which may result in bank stabilization and increased habitat for introduced fishes. Flow effects on the availability of shoreline eddy habitat, bank stabilization due to exotic vegetation overgrowth, and abundance of channel catfish and other potential competitor and predator non-native fishes, remains poorly known in the Green River basin. The few captures of humpback chubs in Whirlpool Canyon in recent years (relative to earlier decades) indicates a general decline of Gila in that system. This may be due to cooler temperatures from Flaming Gorge Dam operations. Razorback sucker Razorback suckers spawn in the Jensen area of the upper Green River, with increasing and highest spring flows that are maintained by runoff from the Yampa River. Curtailment of spring runoff in the mainstream Green River and consequent colder river temperatures downstream from Flaming Gorge Dam, may be related with the loss of recruitment in this species. Flooding of lowlands during spring runoff is considered beneficial to adults and may be important for dispersal and rearing of young. Shallow, flooded areas would also heat more rapidly than the river, and provide more favorable rearing temperatures. Flaming Gorge releases should provide spring flooding of spawning areas and lowlands to aid in reestablishment of razorback sucker. Influence of spring 26