The Last of the Apache

By Dan Davies

The diversity of trout found in the western United States is remarkable and a valuable gift of biodiversity.  The Apache trout (Oncorhynchus apache) are an endemic species of salmonid recognized as the state fish of Arizona. This native trout is distributed exclusively among a relatively small region of watersheds in east-central Arizona and has undergone a significant population decline prior to federal protection.  The Apache trout is closely related to the Gila trout (Oncorhynchus gilae) however is uniquely characterized by yellow coloration, uniform spotting above and below the lateral line, and cream-colored fin tips (Miller 1972). These opportunistic feeders reside in cold-water streams and rivers above 6000 ft elevation where spawning occurs in gravel beds.

The historic range of the Apache trout is known to have included approximately 600 miles of rivers and streams within Arizona's White Mountains. The White, Black and Little Colorado River Basins comprise the waterways within the region (Rinne 1985, Loundenslager et al. 1986, Carmichael et al. 1993). Current distribution of the Apache trout includes only a fraction of their original range at 119 miles and only 28 natural populations of Apache trout remain within their historic range.

                    Original native range of Apache trout. (nativeflyfishing.com, Data: Behnke 2002 and Propst et al 1992.

The Endangered Species Conservation Act of 1967 (a precursor to the Endangered Species Act of 1973) first listed the Apache trout as endangered, however a reclassification to athreatened listing occurred in 1975 following successful reintroductions and reevaluations of population size (USFWS 2009)

Habitat alterations and negative interactions with non-native trout species have been the primary causes of a decline in Apache trout numbers. Critical riparian habitats within the Apache trout range have been heavily disrupted by logging, livestock grazing, reservoir construction, agriculture, and road construction (USFWS 1983). Competition with non-native trout species such as the brown and brook trout have dramatically affected the native populations of Apache trout. Although current federal protection regulates the harvest of Apache trout, overharvesting in the late 1800s and early 1900s was a major factor for the decline in their population.

The original recovery plan for the Apache trout was established in 1983 in order to address the major threats to the species.  The recovery plan mandated that natural and artificial fish barriers be created and or maintained in order to ensure isolation of the natural Apache populations.  Non-native trout species were also chemically or mechanically removed from waterways critical to the endemic Apache and the stocking of non-native trout species has been dramatically reduced. Sport fishing has been banned or closely regulated in streams known to possess relict Apache trout and hatchery produced Apache have been introduced to assist populations or to allow for anglers to catch Apache in designated areas. Fencing erected along streams to control livestock grazing was also established and has shown varying degrees of success. The stream fencing is intended to reduce erosion and sedimentation along these critical riparian habitats (USFWS 2009). A recovery goal of establishing 30 self-sustaining distinct populations has been suggested and appears likely with sound management and restoration efforts. 

Carmichael, G.J., J.N. Hanson, M.E. Schmidt, and D.C. Morizot. 1993. Introgression among Apache, cutthroat, and rainbow trout in Arizona. Transactions of the American Fisheries Society 122:121-130.

Loudenslager, E.J., J.N. Rinne, G.A.E. Gall, and R.E. David. 1986. Biochemical genetic studies of native Arizona and New Mexico trout. Southwestern Naturalist 31:221-234.

Miller, R.R. 1972. Classification of the native trouts of Arizona with the description of a new species, Salmo apache. Copeia 1972:401-422.

Rinne, J.N., and W.L. Minckley. 1985. Patterns of variation and distribution in Apache trout (Salmo apache) relative to co-occurrence with introduced salmonids. Copeia 1985:285- 292.

U.S. Fish and Wildlife Service. 1983. Recovery plan for Arizona trout, Salmo apache, Miller, 1972. Apache Trout Recovery Team. USFWS, Albuquerque, NM, 38 pp.

U.S. Fish and Wildlife Service. 2009. Apache Trout Recovery Plan, Second Revision. Albuquerque, New Mexico.