Population structure of Apache trout (Oncorhynchus apache) in Flash and Squaw creeks on the Fort Apache Indian Reservation, Arizona

Abstract

In 1995, Squaw and Flash creeks were renovated with Antimycin-A to eradicate non-native fish. After renovation, 129 Apache trout from Flash Creek were introduced into Squaw Creek. Two years later, all size classes were present. Apache trout above a natural barrier on Flash Creek were allowed to repopulate the renovated section. Three years later, 45 Apache trout were found below the natural barrier. In both streams, adults selected deep, slow moving areas. Juveniles selected shallow areas with fast currents. Both size classes selected open areas exposed to sunlight with surface turbulence and other forms of instream cover. Apache and Gila trout were experimentally PIT-tagged in the: (1) pelvic girdle; (2) abdominal cavity; and (3) dorsal musculature to determine the best tagging location. Fish tagged in the dorsal musculature had 0% tag loss and 98% survival. The minimum size Apache and Gila trout could be tagged was 90 mm TL.