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6 Other Species Fishes collected during regular sampling were processed soon after capture. Total lengths, weights and Lernaea sp. counts were recorded for each fish collected from all gears except seining. Fish collected from seine hauls were identified, tabulated, checked for Lernaea sp. and released. Flay tags (red) were attached at the base of the dorsal fin of fish 250 mm or longer. Habitat Parameters Depth, current velocity and substrate data were recorded with each capture of a target fish. Depth was measured with a Philadelphia rod or a Lowrance Model LRG 1510-A sonar depth finder. Current velocities were obtained using a Marsh-McBirney Model 201 current meter. The meter sensor was placed on a Philadelphia rod and velocities were read at a point approximately 0.6 of the distance from the water surface to the river bottom, at the site where an endangered fish was captured. Primary and secondary substrate at capture sites were recorded (Appendix A). Analyses The Gunnison and Dolores rivers were divided into three and four homogenous strata, respectively, to provide spatial comparisons for total fish species and numbers. Species composition and catch per unit effort (CPE) were compared between strata, habitats and flow periods. CPE was divided into two groups, those quantified by time and area. Catches using electrofishing. trammel nets, gill nets and fyke nets were combined to yield CPE for hour- related gears. CPE values for hour gears pertain more to larger fish (>100 rom) because the gear types used were selective for larger fish. Catches from all seines (1/8, 114 and l/2-in. mesh) were combined to yield the area CPE. The area CPE values (because of gear selectivity) reflect catch for smaller fishes. CPE was calculated for each species captured with area and hour-based gears. Use of the two CPE combinations for comparative purposes is justified because similar field routines were employed during each sampling trip. Data were stored and recovered in a computer sytem called MANAGE (Valdez and Wilcott 1980). Three datasets, PHYSICAL. CATCH and RARE, contain all data collected from the Gunnison and Dolores rivers. Each data set has 21, 20 and 29 searchable fields. respectively. The PHYSICAL dataset has all data pertaining to water chemistry ~nd physical characteristics of the two rivers. The CATCH dataset contains data on all fish species from each specific sample taken, and RARE has data from endangered fishes.