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along a transect that passed through the center of the area sampled. These values were then averaged for each seine haul. Dominant substrate type was estimated visually and by feel. For analysis, the substrate code was given a numeric value equal to the mid-point of the range of particle sizes given by Hynes ([1970] silt - 0.07 mm, sand - 1.1 mm, gravel - 9 mm, rubble - 16 mm). i Multiple discriminant analysis (Green 1979) was used to compare habitats used by age-0 Colorado squawfish with those used by each of six common sympatric species (red shiner Notronis lutrensis, sand shiner N. stramineus, channel catfish Ictalurus punctatus, speckled dace Rhinichthvs osculus, fathead minnow Pimephales promelas, and Gila spp.). Discriminant analysis allows a researcher to "discriminate" between groups on the basis of a set of habitat characteristics, to determine how well the groups discriminate, and to determine which habitat characteristics are the most powerful discriminators (Klecka 1984). Discriminant analysis employs a simple linear combination (canonical discriminant function) of the discriminating variables to maximize, the separation among the groups. The relative contribution of the discriminating variables to the separation of groups along the canonical function is measured by the correlation between the variables and the dependent canonical factors. Wilks' lambda is a multivariate measure of group differences over the discriminating variables (Klecka 1984). Lambda is an inverse measure of the group differences such that a value of zero represents complete discrimination between the groups and a value of one represents no discrimination between groups. The discriminating habitat variables used in this analysis were mean water depth, mean water-column velocity and dominant substrate size. The variables were weighted according to the catch per effort (C/E; number of fish/mz seined) for each species in the seine haul and were t 1