Summer habitat use by Apache trout (Oncorhynchus apache) in five streams on the Fort Apache Indian Reservation

Abstract

In the summer, five creeks on the Fort Apache Indian Reservation were examined. Apache trout generally selected the deepest pools with the greatest amounts of instream cover and bankcuts. Though fish in three creeks may be Apache trout x rainbow trout hybrids, they were found to occupy the same type of pools. Regression models on environmental conditions in two creeks accounted for 83% and 76% of the variability in biomass of Apache trout. There was adequate nursery habitat (and successful reproduction) on two creeks, but such habitat was lacking in the other three creeks, and no evidence of successful reproduction was found. There was little evidence of survival of smaller Apache trout in areas of co-occurrence with non-native trouts but there was evidence of their survival upstream where fewer numbers of non-natives occur. The exclusion of smaller Apache trout may be from elimination or emigration. Greater populations of Apache trout may be supported through eradication of non-native trouts, the addition of instream cover, and structures designed to create longer lasting pools and bankcuts.