In Arizona, various nonnative trout have been stocked since the early 1900s, and trout angling remains an important component of the sportfishing industry. These nonnative rainbow trout may have contributed to the decline of Little Colorado spinedace. The overall purpose of the research was to define interactions so that impacts to both trout management and spinedace populations can be minimized. Our objectives covered 5 broad areas of potential interaction: habitat use, diet, predation, health, and distribution.

This project consisted of multiple activities: Fish salvage, fish holding and repatriation, stream renovation, fish barrier construction and watershed stock tank renovations. Fish salvage and restocking operations were done in coordination and in conjunction with USFWS and a larger research project being conducted by NAU through separate funding. Brief information on methods and results from those efforts are provided. The Department, utilizing resources provided directly by USBR and via a grant from the FWS, implemented holding facility construction and operation. The Department coordinated the stream renovation with planning and implementation assistance provided by all the aforementioned partners. The USBR conducted all activities related to the fish barrier design and construction, details of which will not be included in this report.

Apache trout is a federally threatened salmonid native to headwaters of the Little Colorado, Black, and White rivers in east-central Arizona. Decline of Apache trout to threatened status was attributed to over-fishing, habitat degradation and negative interactions (predation, competition and hybridization) with introduced nonnative salmonids. Although over-fishing is no longer considered a threat, habitat degradation and negative interactions with nonnative salmonids continue to threaten Apache trout, and it is towards these threats that recovery actions are directed. While barrier construction began in 1979 and livestock exclusion began in the mid-1980s, the efficacy of these recovery actions at increasing Apache trout abundance and improving habitat condition had not been evaluated. We therefore initiated a study to evaluate the efficacy of riparian fencing and barriers.