| Abstract |
We investigated factors affecting the distribution and abundance of Yellowstone cutthroat trout (YCT), the abundance of all trout, and species richness in several drainages in the upper Snake River basin in Idaho. A total of 326 randomly selected sites were visited within the four study drainages, and of these, there was sufficient water to inventory fish and habitat in 56 of the sites in the Goose Creek drainage, 64 in the Raft River drainage, 54 in the Blackfoot River drainage, and 27 in the Willow Creek drainage. Fish were captured in 36, 55, 49, and 22 of the sites, respectively, and YCT were present at 17, 37, 32, and 13 of the sites, respectively. There was little consistency or strength in the models developed to predict YCT presence/absence and density, trout density, or species richness. Typically, the strongest models had the lowest sample sizes. In the Goose Creek drainage, sites with YCT were higher in elevation and lower in conductivity. In the Raft River drainage, trout cover was more abundant at sites with YCT than without YCT. In the Blackfoot River drainage, there was less fine substrate and more gravel substrate at sites with YCT than at sites without YCT. |
