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Razorback suckers have been tested at water current v~locities of 0.5 to 2.0 ft/sec. at the prescribed temperatures. They were able to swim for 1 hour at velocities less than 1.25 ft/sec and less ~han2 minutes. at a velocities of 2 ft/sec or greater. Due to a wide variability ln'the ;i:). ~ perfot'tDances 9f individual fish, no differences were detectable between temperatures.. The ~ests did show differences as to fish 1ength;cJhe larger fish being able to swim longer at velocities of 1. 25 to 2ft/sec. Swimming performance of Colorado squawfish is currently being tested. Other work is being done on TDS preference in the shuttle box and gradient trough) but is not very far along at this time. Bioassays - Eight inorganic and eight organic compounds are being tested at the University of Idaho on Northern and Colorado squawfish and humpback chub. These include heavy metals, pesticides, herbicides, and other contaminates. Post Larvae, juveniles and subadults are being used in these tests. Colorado squawfish are supplied by hatcheries and Northern squawfish are obtained from the wild and cultured by Idaho. The tests are 96-hour, static bioassays. For each chemical, LD50s are determined at 12, 17, and 22 0 C. Simulated Willow Beach water, artesian well water, and Palouse river water with total dissolved solids levels of 730, 175, and 32 mg/l. respectively are being used with the heavy metals. Before October 1980, Colorado squawfish were not up to the size (50 mm) set for the b ioas58)'.s:. Therefore, Northern squawfish were used instead, and 63 bioassays were performed using 3 to 5 concentra- tions for each chemical and 5 to 20 fish per concentration. All LD50s were determined in simulated Willow Beach water. In November 1980, 20,000 juvenile Colorado squawfish were supplied to Idaho for bio- assays. Some of these have been tested and are proving to be tougher than the Northern squawfish. Postlarva and subadult studies will be completed later this year when these fish become available. About 3,500-4,000 humpback chubs are currently on hand at Idaho) less than a quarter of those needed to complete all bioassays. Therefore, tests on these fish will be postponed until July 1981. Culture - Facilities were set up at Idaho to hold and culture large numbers of fish in various stages of development for bioassay and behavior studies. They consist of fiberglass tanks and aquaria. The temperature and light are controlled in each room. The water is recirculated with about 10% fresh water added. Juvenile Colorado squawfish and the humpbacks are under intense culture at various temperatures. They are being fed a commercial diet of trout feed. Growth in the laboratory has been about equal to that in the hatchery. The Colorado squawfish grew 20 mm while the humpbacks grew 40 mm in 6 weeks at 190 C.. Adult Northern squawfish were captured to experiment with light- temperature induced gonadal development and hormone induced spawning methods. So far about 40 fish have been acclimated to the laboratory situation and are being used in these tests. 115 jj