Inhabits clear and cool mountain creeks (above 2000 m elevation). May bite when handled (Bob, pers. comm., 2006).

Southwestern U.S.A.

North America: Gila River system in New Mexico and Arizona, USA.

endemic to a single nation

United States

Origin: Native

Regularity: Regularly occurring

Currently: Present

Confidence: Confident

Type of Residency: Year-round

Global Range: Subspecies GILAE: Apparent former range: throughout upper Gila drainage in New Mexico and the Verde and Agua Fria drainages in Arizona; probably also native to the San Francisco drainage (Sublette et al. 1990, Propst et al. 1992). Extant naturally in the upper Gila River tributaries in Gila National Forest, New Mexico: Iron, McKenna, Main Diamond, and South Diamond creeks; and in Spruce Creek, San Francisco River drainage. Management actions established populations (at least formerly) in Gap Creek, Verde River drainage, Prescott National Forest, Arizona, and in six other creeks in Gila National Forest, New Mexico: Sheep Corral (Canyon) Creek (tributary of Sapillo Creek), McKnight Creek (tributary of Mimbres River, outside native range, Guzman basin), Little Creek (tributary of West Fork of Gila River), Big Dry Creek (upstream of Golden Link Cabin, San Francisco River drainage), and Trail Canyon and Woodrow Canyon creeks along East Fork of Mogollon Creek (USFWS 1987, Sublette et al. 1990). Total present distribution is not more than about 40 stream kilometers. Trout in upper White Creek, New Mexico, may be pure Gila trout (speculation, Sublette et al. 1990). In the late 1980s, a forest fire and related after-effects eliminated the Main Diamond Creek population, and drought and forest fire-related impacts reduced the South Diamond Creek population by more than 95% (Propst et al. 1992). Also in the late 1980s, flooding effects reduced the population in McKnight Creek, but the population was expected to recover, aided by stocking (Propst et al. 1992). In the mid- to late 1980s, populations in Iron and Spruce Creeks appeared to be secure and populations appeared to be established in Dry Creek and Trail Canyon; status in Sheep Corral Canyon and Gap Creek was tenuous due to limited habitat and low abundance (Propst et al. 1992). MtDNA evidence indicates that the McKenna Creek population may be contaminated with genes of O. MYKISS (Riddle, in Propst et al. 1992). USFWS (1990) reported the recent transfer of fishes from Iron Creek to Sacaton Creek; this action was taken only to have a replicate of the Iron Creek population until a larger, more suitable stream is renovated (Propst et al. 1992). Sublette et al. (1990) discussed an early mention of a supposed native salmonid (perhaps O. GILAE or a close relative) formerly present in the Mimbres River, New Mexico, and elsewhere in mountainous regions of the Guzman basin in Chihuahua, Mexico. However, Behnke (1992) suspected that this supposed "trout" record actually was based on the Chihuahua chub. Subspecies APACHE: Historically occurred in Arizona in the upper Salt River division of the Gila River basin (Black and White rivers), in the headwaters of Little Colorado River drainage, and in the Blue River (specimen from KP Creek) in the San Francisco River drainage; these streams all are close to each other in the White Mountains (Behnke 1992). Introduced in several streams and lakes in Arizona. Mainly in small headwater streams above 1800 m in the White Mountains (Behnke 1992).

Historic Range:
U.S.A. (AZ, NM)

Southwestern U.S.A.

Maximum size: 320 mm TL

Maximum size: 320 mm TL

32.0 cm TL (male/unsexed; (Ref. 5723))

Length: 26 cm

demersal; freshwater

Systems

• Freshwater

Habitat Type: Freshwater

Comments: Subspecies GILAE: Clear, cold mountain streams in arid regions; streams largely intermittent (not flowing in summer and fall) (Behnke 1979). Clear runs in mountain streams that typically are narrow and shallow; may be confined to pools during prolonged drought (Sublette et al. 1990). Usually congregates in deeper pools and in shallow water only where there is protective debris or plant beds (Matthews and Moseley 1990).

Subspecies APACHE: Presently restricted to clear, cool, high-elevation mountain streams that flow through cienegas (marshes) and coniferous forests, upstream from natural barriers. Introduced into several streams and lakes.

Spawns in flowing water in saucer-like depression excavated by female. Eggs are covered with gravel after fertilization takes place (Minckley 1973).

Non-Migrant: Yes. At least some populations of this species do not make significant seasonal migrations. Juvenile dispersal is not considered a migration.

Locally Migrant: Yes. At least some populations of this species make local extended movements (generally less than 200 km) at particular times of the year (e.g., to breeding or wintering grounds, to hibernation sites).

Locally Migrant: No. No populations of this species make annual migrations of over 200 km.

Subspecies APACHE: Migrates between spawning and nonspawning areas.

Comments: Subspecies GILAE: Feeds opportunistically on insects and insect larvae (e.g.: Trichoptera, Ephemeroptera, Diptera, Coleoptera, simuliid larvae, terrestrial organisms). Subspecies APACHE: Feeds on aquatic and terrestrial insects (e.g., Ephemeroptera, Trichoptera, and Diptera).

Note: For many non-migratory species, occurrences are roughly equivalent to populations.

Estimated Number of Occurrences: 21 - 80

Comments: Subspecies GILAE: Prior to 1989, five native populations were restored, and six to seven additional populations were established within the historic range (USFWS 1987, Propst et al. 1992). Natural events in 1988 and 1989 eliminated one population and severely reduced two others; a fourth population (natural) may be contaminated with genes of O. MYKISS and its replicate (Propst et al. 1992). Additional populations need to be established (Brown et al. 2001). Subspecies APACHE: Genetically pure populations are confined to 48 km (1979); 13 populations.

10,000 to >1,000,000 individuals

Comments: Subspecies GILAE: Population from 1974-1976 census was less than 7,600, with 4,750 in Main Diamond Creek, New Mexico. Recent count yielded a population estimate of 37,000 individuals, up from 10,000 in the early 1990s (T. Scheffler, pers. com., 2001). Subspecies APACHE: Bonita Creek and East Fork White River may carry several thousand trout.

See Turner (1989) for information on seasonal and annual population changes in subspecies GILAE in headwater streams in New Mexico. Populations of subspecies APACHE become depleted during severe winters.

Comments: Subspecies GILAE: Peak feeding period is 0900-1300 h (Sublette et al. 1990).

Reproductive strategy: synchronous ovarian organization, determinate fecundity (Ref. 51846).

Subspecies GILAE: Spawns apparently in spring and summer in New Mexico (March-June when water temperature is 8 C or greater). Egg production is considered low (usually a few hundred or fewer). Fry emerge in 45-60 days at 20-25 TL (Lee et al. 1980), or in 8-10 weeks at 15-20 mm TL (Sublette et al. 1990). Females sexually mature at 3-5 years, depending on conditions; males mature usually 1-2 years sooner than do females in the same stream (Sublette et al. 1990). Maximum lifespan is 5-9 years in different streams.

Subspecies APACHE: Reaches maturity in three years. Spawning occurs March-mid June, when water temperature about 8 C. Egg production is variable, (70-4000+ per female), usually listed as 200-600. Hatches at 30 days, young emerge at 20-25 mm SL in 60 days (Lee et al. 1980).

See Stearley (1992) for a discussion of the historical ecology and life history evolution of Pacific salmons and trouts (Oncorhynchus).

Year Assessed

• Needs updating

Assessor/s

Reviewer/s

United States

Rounded National Status Rank: N3 - Vulnerable

Rounded Global Status Rank: G3 - Vulnerable

Reasons: Small range in New Mexico and Arizona; negatively impacted by introduced trout and habitat degradation; significant management has occurred; may be conspecific with rainbow trout.

Current Listing Status Summary

Status: Threatened
Date Listed: 03/11/1967
Lead Region:   Southwest Region (Region 2) 
Where Listed:


Population detail:

Population location: entire
Listing status: T

For most current information and documents related to the conservation status and management of Oncorhynchus gilae , see its USFWS Species Profile

Global Short Term Trend: Decline of 10-30%

Comments: USFWS (1990) categorized the status of subspecies GILAE as "declining." Recent data indicate an increasing population (T. Scheffler, pers. comm., 2001). Subspecies APACHE: The estimated historic distribution of 950 km of stream habitat was reduced to about 50 km before restoration efforts began (Behnke 1992). USFWS (1990) categorized the status as "declining."

Global Long Term Trend: Decline of 50-70%

Endangered (EN) (B2ad+3c)

Degree of Threat: A : Very threatened throughout its range communities directly exploited or their composition and structure irreversibly threatened by man-made forces, including exotic species

Comments: Subspecies GILAE: Declined mainly due to hybridization and competitive/predatory interactions with introduced trout species (rainbow, cutthroat, brown) and to habitat degradation through overgrazing, fires, lumbering, and mining (Sublette et al. 1990). Natural catastrophes such as drought, fires, and flooding can decimate populations (Propst et al. 1992, Brown et al. 2001). Subspecies APACHE: Suffered 95% reduction in range due to hybridization with rainbow trout and competition with brook and brown trouts (Lee et al. 1980). Much more vulnerable to angling exploitation than is the brown trout when the two live together in the same stream (see Behnke 1992). Release of hatchery-produced fishes into waters in which pure wild populations exist probably would be detrimental.

Global Protection: Few (1-3) occurrences appropriately protected and managed

Comments: Apache tribe has limited fishing and created Christmas Tree Lake to preserve trout of subspecies APACHE.

Needs: Protect existing EOs from habitat degradation and hybridization with other trout.

Comments: Regulations have been proposed that would allow sport fishing of subspecies GILAE in New Mexico (USFWS 1987); this is not expected to interfere with recovery.

Comments: Subspecies gilae: Hybridizes with rainbow trout (e.g., in Gila National Forest in Black Canyon, Langstroth, Lipsey, upper Mogollon, White, and Sycamore Canyon creeks; see Sublette et al. 1990). Chitty, Sycamore, Lipsey, and W. F. Mogollon creek populations are rainbow trout, apparently with introgressed gilae genes (Loudenslager et al. 1986).

Subspecies apache: Hybridizes with O. mykiss. Populations in Ft. Apache Indian Reservation are more genetically pure than those in Apache-Sitgreaves National Forest (Rinne and Minckley 1985). Paddy Creek population apparently comprises apache-mykiss hybrids (Loudenslager et al. 1986). Allozyme and mtDNA data may yield different conclusions regarding gene exchange between Apache trout and rainbow trout; exteme care must be exercised when considering elimination of any population that is presumed to be genetically contaminated based on allozyme data alone (Dowling and Childs 1992).

MtDNA data indicate that the nominal species O. apache and O. gilae are very similar to each other, and more similar to rainbow trout (O. mykiss) than to cutthroat trout (O. CLARKI) (Dowling and Childs 1992). Data from karyotyping, electrophoresis, and mtDNA comparisons indicate a close genetic relationship between Gila and Apache trout, much closer than among the four major subspecies of cutthroat trout (Behnke 1992). For this reason, Behnke (1992) recognized the Gila and Apache trouts as two subspecies of a single species, O. gilae. He stated that further taxonomic revisions, based on quantitative genetic data and the lack of reproductive isolation, might classify Gila and Apache trout as subspecies of rainbow trout. Behnke (2002) retained gilae and apache as subspecies of O. gilae, noting that recognition of O. gilae is a compromise between taxonomic splitting (treating gilae and apache as different species) and lumping (including gilae and apache as subspecies of O. mykiss). The latest AFS checklist (Nelson et al. 2004) also regarded apache as a subspecies of O. gilae.

MtDNA data indicate the presence of a diagnosable Gila trout (narrow sense) lineage in four relictual populations from the Gila River and San Francisco River drainages, New Mexico; results suported recognition of a O. gilae/apache ESU (evolutionarily significant unit); also, mtDNA data indicated that the population in the Gila River drainage should be treated as a separate management unit relative to the San Francisco drainage (Riddle et al. 1998).

Formerly included in the genus Salmo (see Smith and Stearley 1989, Robins et al. 1991).