Federal Register: May 11, 2005 (Volume 70, Number 90)

DOCID: FR Doc 05-9121

SUBJECT CATEGORY:

Endangered and Threatened Wildlife and Plants; Reclassification of the Gila Trout (Oncorhynchus gilae) From Endangered To Threatened With Regulations

DATES: We will consider all comments on the proposed rule received from interested parties by July 15, 2005. We will hold public hearings on this proposed rule; we have scheduled the hearings for June 28, 2005 in Phoenix, Arizona and on June 29, 2005 in Silver City, New Mexico (see Public Hearing in the SUPPLEMENTARY INFORMATION section of this rule for dates).

DOCUMENT SUMMARY:

We, the U.S. Fish and Wildlife Service (Service), propose to reclassify the federally endangered Gila trout (Oncorhynchus gilae) to threatened status under the authority of the Endangered Species Act of 1973, as amended (Act). Based on a review of the species' current status, we have determined that reclassification of the Gila trout to threatened status is warranted. We are also proposing a special rule under section 4(d) of the Act that would apply to Gila trout found in New Mexico and Arizona. If finalized, the special rule included in this proposal would enable the New Mexico Department of Game and Fish (NMDGF) and the Arizona Game and Fish Department (AGFD) to promulgate special regulations in collaboration with the Service, allowing recreational fishing of Gila trout, beginning on the date that the final 4(d) rule becomes effective.

SUMMARY:

Gila trout; reclassification,

SUPPLEMENTAL INFORMATION

Public Comments Solicited

We intend to make any final action resulting from this proposed rule to be as accurate and as effective as possible. Therefore, we are soliciting comments from the public, other concerned governmental agencies, the scientific community, industry, or any other interested party concerning this proposed rule. We particularly seek comments concerning:

1. The reasons why Gila trout should or should not be reclassified with a special rule, as provided by section 4 of the Act;

2. Information concerning angling opportunities that may be affected by this action in New Mexico or Arizona and how the special rule might affect these uses; and

3. Comments on how the special rule could further the conservation of the Gila trout beyond what we have discussed in this rule. Background

The purposes of the Act are to provide a means whereby the ecosystems upon which endangered and threatened species depend may be conserved and to provide a program for the conservation of those species. Species can be listed as threatened and endangered because of any of the following factors: (1) The present or threatened destruction, modification, or curtailment of its habitat or range, (2) overutilization for commercial, recreational, scientific, or educational purposes, (3) disease or predation, (4) the inadequacy of existing regulatory mechanisms, and (5) other natural or manmade factors affecting its continued existence. When we determine that protection of the species under the Act is no longer warranted, we take steps to remove (delist) the species from the Federal list. If a species is listed as endangered, we may reclassify it to threatened status as an intermediate step before eventual delisting, if it has met the criteria for downlisting to threatened; however, reclassification to threatened status is not required in order to delist.

Section 3 of the Act defines terms that are relevant to this proposal. An endangered species is any species that is in danger of extinction throughout all or a significant portion of its range. A threatened species is any species that is likely to become an endangered species within the foreseeable future throughout all or a significant portion of its range. A species includes any subspecies of fish or wildlife or plants, and any distinct population segment of any species of vertebrate fish or wildlife that interbreeds when mature. Previous Federal Action

The Gila trout was originally recognized as endangered under the Federal Endangered Species Preservation Act of 1966 (32 FR 4001), and Federal designation of the species as endangered continued under the Act (1973). In 1987, the Service proposed to reclassify the Gila trout as threatened (October 6, 1987, 52 FR 37424). However, we withdrew our proposal for reclassification in 1991 (September 12, 1991) (see ``Recovery Plans and Accomplishments'' section below for further information). On November 11, 1996, Mr. Gerald Burton submitted a petition to us to downlist the species from endangered to threatened. We acknowledged receipt of the petition by letter on January 13, 1997. This proposed rule constitutes our 90day finding and 12month finding on the November 11, 1996, petition.

Systematics

The Gila trout is a member of the salmon and trout family (Salmonidae). Gila trout was not formally described until 1950, using fish collected in Main Diamond Creek in 1939 (Miller 1950). It is most closely related to Apache trout (Oncorhynchus apache), which is endemic to the upper Salt and Little Colorado River drainages in eastcentral Arizona. Gila trout and Apache trout are more closely related to rainbow trout (O. mykiss) than to cutthroat trout (O. clarki), suggesting that Gila and Apache trouts were derived from an ancestral form that also gave rise to rainbow trout (Behnke 1992; Dowling and Childs 1992; Utter and Allendorf 1994; Nielsen et al. 1998; Riddle et al. 1998).

Physical Description

The Gila trout is readily identified by its iridescent gold sides that blend to a darker shade of copper on the opercles (gill covers). Spots on the body are small and profuse, generally occurring above the lateral line and extending onto the head, dorsal (back, top) fin, and caudal (tail) fin. Spots are irregularly shaped on the sides and increase in size on the back. On the dorsal surface of the body, spots may be as large as the pupil of the fish eye and are rounded. A few scattered spots are sometimes present on the anal fin, and the adipose fin (fleshy fin located behind dorsal fin) is typically large and well spotted. Dorsal, pelvic, and anal fins have a white to yellowish tip that may extend along the leading edge of the pelvic fins. A faint, salmonpink band is present on adults, particularly during spawning season when the normally white belly may be streaked yellow or reddish orange. A yellow cutthroat mark is present on most mature specimens. Parr marks (diffuse splotches on the sides of body, usually seen on young trout) are commonly retained by adults, although they may be faint or absent (Miller 1950; David 1976).

Characteristics that distinguish Gila trout from other co occurring, nonnative trout include the golden coloration of the body, parr marks, and fine, profuse spots above the lateral line. These characters differentiate Gila trout from rainbow, brown (Salmo trutta), and cutthroat trouts. Roundtail chub (Gila robusta) are locally confused with Gila trout (Minckley 1973). The two species share a similar distribution, although roundtail chub typically occurs at lower elevations than Gila trout currently occupies. The two species may be confused partly because roundtail chub are occasionally caught by anglers fishing where both species occur together. The roundtail chub, a minnow (family Cyprinidae) whose adult size is similar to Gila trout's, differs from Gila trout (family Salmonidae) by its body shape and coloration. The roundtail chub lacks an adipose fin and has a narrow caudal peduncle (the segment of the body to which the tail fin is attached). Also, roundtail chub lack parr marks, golden coloration, yellow cutthroat marks, and
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salmonpink band found on Gila trout. Roundtail chub are typically a mottled olive or dark silver color above the lateral line, and body coloration lightens to a light silvery hue below the lateral line (Sublette et al. 1990).

Distribution and Threats

The extent of the historical distribution of the Gila trout is not known with certainty (Behnke 2002). It is known to be native to higher elevation streams in portions of the Gila River drainage, New Mexico. According to anecdotal reports, in 1896 Gila trout were found in the Gila River drainage, New Mexico, from the headwaters downstream to a box canyon, about 11.3 km (7 mi) northeast of Cliff, New Mexico (Miller 1950). By 1915, the downstream distribution of Gila trout in the Gila River had receded upstream to Sapillo Creek, a distance of approximately 25 km (15 mi) (Miller 1950). By 1950, water temperature in the Gila River at Sapillo Creek was considered too warm to support any trout species (Miller 1950). The earliest documented collections of Gila trout in the upper Gila River drainage were in 1939, from Main Diamond Creek (Miller 1950). New populations were sporadically found until 1992 when Gila trout were discovered in Whiskey Creek, a tributary to the upper West Fork Gila River (Service 2003).

Miller (1950) documented changes in suitability of habitats for Gila trout in the upper Gila drainage. Unregulated livestock grazing and logging likely contributed to habitat modifications noted by Miller (1950). The historical occurrence of intensive grazing and resulting effects on the land (e.g., increased sedimentation by removal of riparian vegetation and increased runoff rates due to soil compaction) are indicated in published reports dating back to the early 1900s (Rixon 1905; Rich 1911; Duce 1918; Leopold 1921; Leopold 1924). Logging activities also likely caused major changes in watershed
characteristics and stream morphology. Rixon (1905) reported the occurrence of small timber mills in numerous canyons of the upper Gila River drainage. Early logging efforts were concentrated along canyon bottoms, often with perennial streams. Tree removal along perennial streams within the historical range of Gila trout likely altered water temperature regimes, sediment loading, bank stability, and availability of large woody debris (Chamberlin et al. 1991).

When the Gila trout was listed as endangered, it was thought that its range had been reduced to five streams within the Gila National Forest, New Mexico: Iron, McKenna, Spruce, Main Diamond, and South Diamond. In 1998, it was determined that the McKenna and Iron Creek populations had hybridized with rainbow trout and therefore, did not contribute to the recovery of the species because they are not pure (Leary and Allendorf 1998; Service 2003). In 1992, another original pure population (i.e., relict population) of Gila trout was discovered in Whiskey Creek (Leary and Allendorf 1998). Consequently, there are four confirmed original pure populations known today. Reasons for listing the Gila trout as endangered included hybridization, competition, and/or predation by nonnative rainbow, cutthroat, and brown trout, and habitat degradation.

Occurrence of Gila trout in tributaries to the Gila River in Arizona is less certain, although these streams harbored a native trout. Native trout occurred in the Eagle Creek drainage, a tributary of the Gila River in Arizona located west of the San Francisco River drainage (Minckley 1973; Kynard 1976). The identity of this native trout, now lost through hybridization with rainbow trout, is uncertain (Marsh et al. 1990). Native trout were reported from Oak Creek, a tributary to the Verde River, before the turn of the century (Miller 1950). Four specimens collected from Oak Creek before 1890 were ascribed to Gila trout (Miller 1950; Minckley 1973). Native trout were also reported from West Clear Creek, another Verde River tributary (Miller 1950). Trout collected in 1975 from Sycamore Creek, a tributary of Agua Fria, were reported to be Gila x rainbow trout hybrids. However, this determination was based solely on examination of spotting pattern (Behnke and Zarn 1976). Unfortunately, no pure Gila trout are extant from Arizona tributaries to the Gila River and scientists are unable to make a clear determination of the identity of the four remaining preserved specimens that were collected from Oak Creek (Miller 1972).

Habitat Characteristics

Nursery and rearing habitats are areas used by larval and juvenile Gila trout. Although no studies have been done on habitat use by these life stages of Gila trout, generalizations can be made based on characteristics of related trout species. Suitable nursery habitat for trout includes areas with slow current velocity such as stream margins, seeps, shallow bars, and side channels (Behnke 1992). Low flows during emergence from the egg and early growth of larval trout may result in strong year classes (young fish are not displaced downstream) (Behnke 1992), as may constant, elevated flows during summer (improved water quality) (Service 2003). Absence of predation by nonnative trout, particularly brown trout, is another essential element of nursery and rearing habitat.

Subadult and adult habitats are defined as areas suitable for survival and growth of these life stages. Subadults are sexually immature individuals, generally less than 150 millimeters (mm) (6 inches (in)) total length and adults are sexually mature individuals typically greater than 150 mm (6 in) total length (Propst and Stefferud 1997). Subadult Gila trout occur primarily in riffles (shallow water flowing over cobbles), riffleruns, and runs, while adults are found mainly in pools (Rinne 1978). Cover (large woody debris, undercut banks, boulders, deep water, and overhanging woody and herbaceous vegetation) is an important component of subadult and adult habitat (Stefferud 1994). The quantity and quality of adult habitat typically limits the trout population biomass (Behnke 1992). Essential elements of subadult and adult habitat relate principally to channel dimensions, cover, and hydrologic variability. Absence of competition with non native trouts (brown and rainbow) for foraging habitat is also an essential element of subadult and adult habitat.

Variation in stream flow is a major factor affecting subadult and adult population size (McHenry 1986, Turner 1989, Propst and Stefferud 1997). In particular, high flow events may cause marked decrease in population size. These events result in shortterm, radical changes in habitat conditions, primarily in flow velocity. Because most streams occupied by Gila trout have relatively narrow floodplains, the forces associated with high flow events are concentrated in and immediately adjacent to the bankfull channel. High stream flow velocities cause channel scouring and displacement of fish downstream, often into unsuitable habitats (Rinne 1982).

Overwintering habitat is defined as areas that afford shelter during periods of low water temperature, generally from November through February. Rinne (1981) and Propst and Stefferud (1997) indicated the importance of pool habitat for overwinter survival of Gila trout. Essential elements of overwintering habitat are deep water with low current velocity and protective cover (Behnke 1992). These elements are important because small streams can freeze, but the presence of deep pools provides areas that do not freeze. Trout are typically more sluggish in the winter and cover is important to protect them
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from predators. Barriers to fish movement (e.g., waterfalls, dry stream bed) that prevent fish from accessing overwintering habitat may impact populations of Gila trout. Gila trout are now restricted to small headwater streams that typically have fewer deep pools and less suitable overwintering habitat than do larger streams (Harig and Fausch 2002).

Life History

Spawning occurs mainly in April (Rinne 1980) when temperatures are 6 to 8[deg]C (43 to 46[deg]F); however, day length may also be an important cue. Stream flow is apparently of secondary importance in triggering spawning activity (Rinne 1980). Young fish less than 25 mm (1.0 in) in length emerge from gravel nests 56 to 70 days after egg deposition (Rinne 1980). By the end of their first summer, young attain a total length of 70 to 90 mm (2.7 to 3.5 in) at lower elevation streams and 40 to 50 mm (1.6 to 2.0 in) at higher elevation sites (Rinne 1980; Turner 1986). Growth rates are variable, but Gila trout generally reach 180 to 220 mm (7.1 to 8.7 in) total length by the end of the third growing season in all but higher elevation streams. On average, for every 100 eggs that hatch, only two fish will survive to become adults (Brown et al. 2001).

Females reach maturity at age 2 to 4 at a minimum length of about 130 mm (5 in) (Nankervis 1988, Propst and Stefferud 1997). Males typically reach maturity at age 2 or 3. Most Gila trout live to about age 5 (Turner 1986), with a maximum age of 9 reported by Nankervis (1988). Thus, the majority of female Gila trout only spawn once and most males only spawn two or three times.

Aquatic insects are the primary food of Gila trout. Regan (1966) reported that adult flies, caddisfly larvae, mayfly nymphs, and aquatic beetles were the most abundant food items in the stomachs of Gila trout in Main Diamond Creek. There was little variation in food habits over the range of size classes sampled (47 to 168 mm (1.8 to 6.6 in) total length). Gila trout diet shifted seasonally as the relative abundance of various prey changed. Insect taxa consumed by Gila trout were also common in stomach contents of nonnative trout species in the Gila River drainage, indicating the potential for interspecific competition. Hanson (1971) noted that Gila trout established a feeding hierarchy in pools during a low flow period in Main Diamond Creek. Larger fish aggressively guarded their feeding stations and chased away smaller fish. Large Gila trout occasionally consume speckled dace and may also cannibalize smaller Gila trout (Van Eimeren 1988; Propst and Stefferud 1997).

Adult Gila trout are typically sedentary and movement is influenced by population density and territoriality (Rinne 1982). Although individual fish may move considerable distances (e.g., over 1.5 km (0.9 mi)), Rinne (1982) found that after eight months, 75 percent of tagged fish were less than 100 m (328 ft) from their release sites in Main Diamond, South Diamond, and McKnight Creeks. Gila trout showed a tendency to move upstream in South Diamond Creek, possibly to perennial reaches with suitable pool habitat in response to low summer discharge. Downstream movement in Main Diamond and McKnight Creeks involved primarily smaller fish and probably occurred because of nocturnal migrations (nighttime dispersal) or displacement downstream during flooding (Rinne 1982). High density of log structures in Main Diamond Creek appeared to reduce mobility of Gila trout in that stream (Rinne 1982).

Factors affecting population size and dynamics of Gila trout are not well understood. Inferences about factors that control population size have been made from analysis of timeseries data (Turner and McHenry 1985, Turner 1989, Propst and Stefferud 1997). Hydrologic variability appears to be most important in regulating population size of Gila trout in many of the streams occupied by the species (e.g., Regan 1966, Mello and Turner 1980, McHenry 1986, Turner 1989, Brown et al. 2001). Gila trout populations typically have high densities during relatively stable flow periods (Platts and McHenry 1988). The overall importance of environmental factors, specifically drought and flooding, that can occur following a fire due to a loss of vegetation, are critical factors in determining persistence of Gila trout populations. Examples of the effects of severe wildfires and subsequent floods and ash flows are the elimination of the Gila trout populations from Main Diamond Creek (1989) and South Diamond Creek (1995).

Recovery Plans and Accomplishments

The original recovery plan for Gila trout was completed in 1979. The main objective of this recovery plan was ``To improve the status of Gila trout to the point that its survival is secured and viable populations of all morphotypes are maintained in the wild'' (Service 1979). The Gila Trout Recovery Plan was revised in 1984 with the same objective as the original plan. Downlisting criteria in the plan stated that ``The species could be considered for downlisting from its present endangered status to a threatened status when survival of the four original ancestral populations is secured and when all morphotypes are successfully replicated or their status otherwise appreciably improved'' (Service 1984). Replication involves either moving individuals from a successfully reproducing original pure or replicated population or taking hatcherypropagated fish and releasing them into a renovated stream. In 1987, we proposed that Gila trout be reclassified from endangered to threatened with a special rule to allow sport fishing (52 FR 37424). At that time, Gila trout populations were deemed sufficiently secure to meet criteria for reclassification to threatened as identified in the Plan (52 FR 37424). However, the proposed rule to downlist Gila trout was withdrawn in 1991 (September 12, 1991, 56 FR 46400) because:

1. Severe flooding in 1988 reduced the Gila trout populations in McKnight Creek by about 80 percent;

2. Wild fires in 1989 eliminated Gila trout from Main Diamond Creek and all of the South Diamond drainage except Burnt Canyon, a small headwater stream;

3. Propagation activities at hatcheries had not proceeded as planned and fish were not available to replenish wild stocks; and

4. Brown trout, a predator, was present in Iron Creek, which at the time was thought to harbor one of the original pure populations of Gila trout.

The Gila Trout Recovery Plan was revised in 1993 to incorporate new information about ecology of the species and recovery methods. Criteria for downlisting remained essentially the same as in the 1984 revision but were more specific. The 1993 plan specified that downlisting would be considered ``when all known indigenous lineages are replicated in the wild'' and when Gila trout were ``established in a sufficient number of drainages such that no natural or humancaused event may eliminate a lineage.'' The recovery plan was revised again in 2003 (Service 2003). The criteria for downlisting in the 2003 Recovery Plan include the following: (1) The four known nonhybridized indigenous lineages are protected and replicated in the wild in at least 85 km (53 mi) of streams; (2) each known nonhybridized lineage is replicated in a stream geographically separate from its remnant population such that no natural or humancaused event may eliminate a lineage; and (3) [[Page 24754]]
an Emergency Evacuation Procedures Plan for Gila Trout (Emergency Plan) to address wildfire impacts and discovery of nonnative salmonid invasion in Gila trout streams has been developed and implemented.

Today three of the four original pure populations (Main Diamond, South Diamond, and Spruce Creeks) are replicated at least once. The Service believes the three replicated populations are secure and the viability of the Gila trout is sufficiently protected through these three populations. The species is no longer in danger of extinction. Whiskey Creek, the fourth pure population, is not replicated. The Service believes that a small population of Gila trout remains in Whiskey Creek and that it may be possible to replicate the Whiskey Creek population in the future. Work will continue to conserve the Whiskey Creek lineage, if possible. Whiskey Creek is considered a harsh environment, and the Gila trout population there has been in a tenuous situation. A broodstock management plan and an Emergency Plan have been completed (Kincaid and Reisenbichler 2002; Service 2004). Recovery actions have included chemically treating streams within the historic range of the species to remove nonnative fish species, removing non native trout by electrofishing, and constructing physical barriers to prevent movement of nonnatives into renovated reaches (Service 2003).

Surveys of the 12 existing populations indicate that the recovery efforts to remove nonnative fish and prevent their return to the renovated areas have been successful (Service 2003). Replicated populations in New Mexico are successfully reproducing, indicating that suitable spawning and rearing habitats are available. Replicated populations in Arizona exist in Raspberry and Dude Creeks. Young of the year were planted in Raspberry Creek in Arizona in 2000. In 2004, Gila trout in Raspberry Creek were found in mixed size classes, indicating that the fish spawned and successfully recruited. Although some fish were removed from Raspberry Creek due to the threat of wildfire, some of these fish were restocked in November 2004 into the uppermost portions of Raspberry Creek, which survived the impacts caused by the fire and which still support Gila trout. The status of the population at Raspberry Creek will be reassessed in 2005. Factors limiting reproduction in Dude Creek in Arizona are not known.

Overall, there has been an increase in the total wild population of Gila trout. In 1992, the wild populations of Gila trout were estimated to be less than 10,000 fish greater than age 1. In 2001, the population in New Mexico was estimated to be 37,000 fish (Brown et al. 2001). As noted above, Gila trout were more recently replicated in Arizona; as such, we do not have estimated numbers of fish at this time. The stream renovation and transplantation efforts have been accomplished jointly by the Service, Forest Service, NMDGF, AGFD, and New Mexico State University. Original pure populations and their replicates are summarized in Table 1.
Table 1.Summary and Status of Streams Inhabited by Gila Trout as of January 2001 (Original Pure Population (i.e., Relict) Lineages in Bold) km (mi) of

State County Stream name Drainage stream Origin inhabited NM.......... Sierra................... Main Diamond Creek................. East Fork Gila River............... 6.1 (3.8) Relict Lineage Eliminated in 1989, reestablished in 1994. NM.......... Grant.................... McKnight Creek..................... Mimbres River...................... 8.5 (5.3) Replicate of Main Diamond, est. 1970. NM.......... Grant.................... Black Canyon....................... East Fork Gila River............... 18.2 (11.3) Replicate of Main Diamond, est. 1998. NM.......... Catron................... Lower Little Creek................. West Fork Gila River............... 6.0 (3.7) Replicate of Main Diamond, est. 2000. NM.......... Catron................... Upper White Creek.................. West Fork Gila River............... 8.8 (5.5) Replicate of Main Diamond, est. 2000. NM.......... Sierra................... South Diamond Creek\1\............. East Fork Gila River............... 6.7 (4.2) Relict Lineage Eliminated in 1995, reestablished in 1997. NM.......... Catron (Grant)........... Mogollon Creek\2\.................. Gila River......................... 28.8 (17.9) Replicate of South Diamond Creek, est. 1987. NM.......... Catron................... Spruce Creek....................... San Francisco River................ 3.7 (2.3) Relict Lineage NM.......... Catron................... Big Dry Creek...................... San Francisco River................ 1.9 (1.2) Replicate of Spruce Creek, est. 1985. AZ.......... Gila..................... Dude Creek......................... Verde River........................ 3.2 (2.0) Replicate of Spruce Creek, est. 1999. AZ.......... Greenlee................. Raspberry Creek.................... Blue River......................... 6.0 (3.7) Replicate of Spruce Creek, est. 2000. NM.......... Catron................... Whiskey Creek...................... West Fork Gila River............... 2.6 (1.6) Relict Lineage \1\ South Diamond Creek includes Burnt Canyon.
\2\ Mogollon Creek includes Trail Canyon, Woodrow Canyon, Corral Canyon, and South Fork Mogollon Creek. Portions of the drainage are in Grant County, New Mexico.

Three of the four original pure population lineages are currently protected and replicated in 100 km (62 mi) of stream, each replicate is geographically separate from its original pure population, and an Emergency Plan has been developed and implemented. The Emergency Plan addresses wildfirerelated impacts and discovery of nonnative salmonid invasions (Service 2004). In 2002, the Emergency Plan (Service 2004) was implemented during the Cub Fire to evacuate fish from Whiskey Creek (Brooks 2002), and in 2003 the plan was implemented during the Dry Lakes Fire to remove fish from Mogollon Creek (J. Brooks, U.S. Fish and Wildlife Service, in litt. 2003b).

Summary of Factors Affecting the Species

Section 4 of the Act and regulations issued to implement the listing provisions of the Act (50 CFR Part 424) set forth the procedures for listing, reclassifying, and delisting species. Species may be listed as threatened or endangered if one or more of the five factors described in section 4(a)(1) of the Act threaten the continued existence of
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the species. A species may be reclassified, according to 50 CFR 424.11(c), if the best scientific and commercial data available substantiate that the species' status at which it is listed is no longer correct. This analysis must be based upon the five categories of threats specified in section 4(a)(1).

For species that are already listed as threatened or endangered, this analysis of threats is primarily an evaluation of the threats that could potentially affect the species in the foreseeable future following the delisting or downlisting and the removal or reduction of the Act's protections. Our evaluation of the future threats to the Gila trout that would occur after reduction of the protections of the Act is partially based on the protection provided by the Gila and Aldo Leopold Wilderness areas, the Emergency Plan, the broodstock management plan, and limitations on take that would be determined by the States in collaboration with us.

After a thorough review of all available information and an evaluation of the five factors specified in section 4(a)(1) of the Act, we are proposing to reclassify the Gila trout as threatened, with a special rule allowing for recreational fishing, due to partial recovery. Discussion of the five listing factors and their application to recovery of the Gila trout are as follows:
A. The Present or Threatened Destruction, Modification, or Curtailment of its Habitat or Range

In the past, Gila trout populations were threatened by habitat degradation and watershed disturbances (52 FR 37424). These factors compounded the threats posed by nonnative salmonids (see Factors C and E below for discussions on nonnative salmonids). We discuss habitat degradation from livestock grazing, timber harvest, and wildfires below.

Livestock Grazing

Intensive livestock grazing has been shown to increase soil compaction, decrease infiltration rates, increase runoff, change vegetative species composition, decrease riparian vegetation, increase stream sedimentation, increase stream water temperature, decrease fish populations, and change channel form (Meehan and Platts 1978; Kaufman and Kruger 1984; Schulz and Leininger 1990; Platts 1991; Fleischner 1994; Ohmart 1996). Although direct impacts to the riparian zone and stream can be the most obvious sign of intensive livestock grazing, upland watershed condition is also important because changes in soil compaction, percent cover, and vegetative type influence the timing and amount of water delivered to stream channels (Platts 1991). Increased soil compaction, decreased vegetative cover, and a decrease in grasslands lead to faster delivery of water to stream channels, increased peak flows, and lower summer base flow (Platts 1991; Ohmart 1996; Belsky and Blumenthal 1997). As a consequence, streams are more likely to experience flood events during monsoons (water runs off quickly instead of soaking into the ground) that negatively affect the riparian and aquatic habitats and are more likely to become intermittent or dry in September and October (groundwater recharge is less when water runs off quickly) (Platts 1991; Ohmart 1996).

Improper livestock grazing practices degrade riparian and aquatic habitats, likely resulting in decreased production of trout (Platts 1991). Livestock affect riparian vegetation directly by eating grasses, shrubs, and trees, by trampling the vegetation, and by compacting the soil. Riparian vegetation benefits streams and trout by providing insulation (cooler summer water temperatures, warmer winter water temperatures), by filtering sediments so that they do not enter the stream (sediment clogs spawning gravel and reduces the survival of salmonid eggs), by providing a source of nutrients to the stream from leaf litter (increases stream productivity), and by providing root wads, large woody debris, and small woody debris to the stream (provides cover for the fish) (Kauffman and Krueger 1984; Platts 1991; Ohmart 1996). Poor livestock grazing practices can increase sedimentation through trampling of the steam banks (loss of vegetative cover), by removal of riparian vegetation (filters sediment), and through soil compaction (decreases infiltration rates, increases runoff, causes increased erosion). Sediment is detrimental to trout because it decreases the survival of their eggs (Bjornn and Reiser 1991), and because of its negative impact on aquatic invertebrates, a food source for trout (Wiederholm 1984).

In the late 1800s and early 1900s, livestock grazing was uncontrolled and unmanaged over many of the watersheds that contain Gila trout, and much of the landscape was denuded of vegetation (Rixon 1905; Duce 1918; Leopold 1921; Leopold 1924; Ohmart 1996). Livestock grazing is more carefully managed now, which has resulted in less impact to streams occupied by Gila trout. Improved grazing management practices (e.g., fencing) have reduced livestock access to streams. Six of the 12 streams currently occupied by Gila trout are within Forest Service grazing allotments. However, as described below, on creeks occupied by Gila trout, grazing has either been suspended or cattle are typically excluded.

Mogollon Creek is within the Rain Creek/74 Mountain Allotment. This allotment receives only winter use, and much of the riparian habitat is inaccessible to livestock. Riparian vegetation along Mogollon Creek is in good condition (A. Telles, U.S. Forest Service, Gila National Forest, in litt. 2003c). Main Diamond Creek and the adjacent riparian zone, located in the South Fork Allotment, are excluded from grazing. The Forest Service is implementing a fencing project along Turkey Run Creek to prevent livestock trespass into Main Diamond Creek (A. Telles, U.S. Forest Service, Gila National Forest, in litt. 2003c).

South Diamond Creek and Black Canyon are within the Diamond Bar Allotment, where grazing was suspended in 1996. This has resulted in marked improvements in the condition of riparian and aquatic habitat in these areas (A. Telles, U.S. Forest Service, Gila National Forest, in litt. 2003c).

In Arizona on the ApacheSitgreaves National Forest, Raspberry Creek, which is located in the Blue Range Primitive Area, includes two grazing allotments, Strayhorse and Raspberry. The Strayhouse Allotment includes about 75 percent of the watershed above the fish barrier. The allotment was evaluated in July 1998, and determined to be in ``Proper Functioning Condition'' (D. Bills, U.S. Fish and Wildlife Service, in litt. 2003d). It has a welldeveloped riparian plant community and no adverse impacts from ongoing livestock grazing (Service 2000). Evaluation of the Raspberry Allotment occurred twice in 1998 and concluded that the allotment was ``FunctionalAt Risk'' and in a ``Downward'' trend (Service 2000). The report noted an incised channel (eroded downward), and concluded that upland watershed conditions were contributing to the riparian degradation. Significant changes were made to the Raspberry Allotment in 2000 (Service 2000). Specifically, the Forest Service required a reduction in livestock numbers to 46 cattle from November 1 to June 14 (or removal of cattle prior to June 14 if utilization standards are reached). Prior to this, 225 cattle were permitted on the Allotment yearlong and 160 cattle were permitted from January 1 to May 15.

Dude Creek, on the Tonto National Forest, is within the East Verde Pasture of the Cross V Allotment. Current management techniques are designed to protect the stream banks and riparian
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vegetation, thereby reducing sedimentation and increasing river insulation (and thereby maintaining cooler summer and warmer winter water temperatures).

Timber Harvest

Logging activities in the early to mid 1900s likely caused major changes in watershed characteristics and stream morphology (Chamberlin et al. 1991). Rixon (1905) reported the occurrence of small timber mills in numerous canyons of the upper Gila River drainage. Early logging efforts were concentrated along canyon bottoms, often with perennial streams. Tree removal along perennial streams within the historical range of Gila trout likely altered water temperature regimes, sediment loading, bank stability, and availability of large woody debris (Chamberlin et al. 1991). Nine of 10 populations in New Mexico exist in the Aldo Leopold Wilderness or Gila Wilderness. Of the two populations in Arizona, Raspberry Creek occurs in the Blue Range Primitive Area. Timber harvest is not allowed in wilderness or primitive areas. There are no plans for timber harvest near the other streams that have Gila trout (A. Telles, U.S. Forest Service, Gila National Forest, in litt. 2003c). If timber harvest were to be proposed in the future, in the two areas located outside of a wilderness or primitive area, the Forest Service would need to consider the effects of the proposed action under section 7 of the Act.

Fire

Highseverity wildfires, and subsequent floods and ash flows, caused the extirpation of seven populations of Gila trout since 1989: Main Diamond (1989), South Diamond (1995), Burnt Canyon (1995), Trail Canyon (1996), Woodrow Canyon (1996), Sacaton Creek (1996), Upper Little Creek (2003) (Propst et al. 1992; Brown et al. 2001; J. Brooks, Service, pers. comm. 2003). Lesser impacts were experienced in 2002 when ash flows following the Cub Fire affected the lower reach of Whiskey Creek. However, lower Whiskey Creek is frequently intermittent and typically contains few fish (Brooks 2002). Upper Whiskey Creek, where the majority of the fish occur, was not affected by the Cub Fire. The Cub Fire also impacted the upper West Fork Gila and may have eliminated nonnative trout from the watershed upstream of Turkey Feather Creek (Brooks 2002). In 2003, fire retardant was dropped on Black Canyon, affecting approximately 200 m (218 yards) of stream (J. Monzingo, U.S. Forest Service, Gila National Forest, in litt. 2003e). Although some Gila trout were killed, the number of mortalities is unknown (J. Monzingo, U.S. Forest Service, Gila National Forest, in litt. 2003e) because dead fish were carried by the current out of the area by the time fire crews arrived. However, a week after the retardant drop, live Gila trout were observed about 400 m (438 yards) below the drop site (J. Monzingo, U.S. Forest Service, Gila National Forest, in litt. 2003e).

Severe wildfires capable of extirpating or decimating fish populations are a relatively recent phenomenon, and result from the cumulative effects of historical or overly intensive grazing (can result in the removal of fine fuels needed to carry fire) and fire suppression (Madany and West 1983; Savage and Swetnam 1990; Swetnam 1990; Touchan et al. 1995; Swetnam and Baisan 1996; Belsky and Blumenthal 1997; Gresswell 1999), as well as the failure to use good forestry management practices to reduce fuel loads. Historic wildfires were primarily coolburning understory fires with return intervals of 37 years in ponderosa pine (Swetnam and Dieterich 1985). Cooper (1960) concluded that prior to the 1950s, crown fires were extremely rare or nonexistent in the region. In 2003, over 200,000 acres burned in the Gila NF (S. Gonzales, U.S. Fish and Wildlife Service, in litt. 2004). The watersheds of Little Creek, Black Canyon, White Creek, and Mogollon Creek were affected. Because Gila trout are found primarily in isolated, small streams, avoidance of ash flows is impossible and opportunities for natural recolonization usually do not exist (Brown et al. 2001). Persistence of Gila trout in streams affected by fire and subsequent ash flows is problematic. In some instances, evacuation of Gila trout from streams in watersheds that have burned is necessary (Service 2004).

Effects of fire may be direct and immediate or indirect and sustained over time (Gresswell 1999). The cause of direct firerelated fish mortalities has not been clearly established (Gresswell 1999). Fatalities are most likely during intense fires in small, headwater streams with low flows (less insulation and less water for dilution). In these situations, water temperatures can become elevated or changes in pH may cause immediate death (Cushing and Olson 1963). Spencer and Hauer (1991) documented 40fold increases in ammonium concentrations during an intense fire in Montana. Ammonia is very toxic to fish (Wetzel 1975). The inadvertent dropping of fire retardant in streams is another source of direct mortality during fires (J. Monzingo, U.S. Forest Service, Gila National Forest, in litt. 2003e).

Indirect effects of fire include ash and debris flows, increases in water temperature, increased nutrient inputs, and sedimentation (Swanston 1991; Bozek and Young 1994; Gresswell 1999). Ash and debris flows can cause mortality months after fires occur when barren soils are eroded during monsoonal rain storms (Bozek and Young 1994; Brown et al. 2001). Fish suffocate when their gills are coated with fine particulate matter, they can be physically injured by rocks and debris, or they can be displaced downstream below impassable barriers into habitat occupied by nonnative trout. Ash and debris flows or severe flash flooding can also decimate aquatic invertebrate populations that the fish depend on for food (Molles 1985; Rinne 1996; Lytle 2000). In larger streams, refugia are typically available where fish can withstand the shortterm adverse conditions; small headwater streams are usually more confined, concentrating the force of water and debris (Pearsons et al. 1992; Brown et al. 2001).

Increases in water temperature occur when the riparian canopy is eliminated by fire and the stream is directly exposed to the sun. After fires in Yellowstone National Park, Minshall et al. (1997) reported that maximum water temperatures were significantly higher in headwater streams affected by fire than temperatures in reference (unburned) streams; these maximum temperatures often exceeded tolerance levels of salmonids. Warm water is stressful for salmonids and can lead to increases in disease and lowered reproductive potential (Bjornn and Reiser 1991). Salmonids need clean, loose gravel for spawning sites (Bjornn and Reiser 1991). Ash and fine particulate matter created by fire can fill the interstitial spaces between gravel particles and eliminate spawning habitat or, depending on the timing, suffocate eggs that are in the gravel. Increases in water temperature and sedimentation can also impact aquatic invertebrates, changing species composition and reducing population numbers (Minshall 1984; Wiederholm 1984; Roy et al. 2003), consequently affecting the food supply of trout.

As discussed above, in the ``Timber'' and ``Grazing'' sections, we have determined that the threats to Gila trout habitat from grazing and timber harvest have been greatly reduced over time. It is expected that the livestock management practices (e.g., exclusion from riparian zones, reduction in numbers, suspension of grazing in some allotments) that have been implemented
[[Page 24757]]
will remain in place (A. Telles, U.S. Forest Service, Gila National Forest, in litt. 2003c). Additionally, the Forest Service will continue to consider the effects of grazing on Gila trout under section 7 of the Act. Presently, 9 of the 10 streams that contain Gila trout occur in the Aldo Leopold Wilderness Area or the Gila Wilderness within the Gila National Forest, New Mexico. Timber harvest, roads, and mechanized vehicles are not allowed in wilderness areas, providing further protection to the habitat of Gila trout. Dispersed recreation does occur in wilderness areas but because of the inaccessibility of most of the streams (not near roads, hiking or backpacking is required), dispersed recreation has very little impact on the habitat. By practice, the NMDGF does not stock nonnative trout within wilderness areas or above any barrier that protects a population of Gila trout. The NMDGF has not stocked nonnative fish in wilderness areas for over 20 years (Mike Sloan, NMDGF, pers. comm. 2004).

Highseverity forest fires remain a threat to isolated populations because natural repopulation is not possible. However, populations have been reestablished after forest fires (Main Diamond and South Diamond Creeks), there is an Emergency Plan (Service 2004) that outlines procedures to be taken in case of a highseverity forest fire, and most populations are sufficiently disjunct (e.g., separated by mountain ridges), thereby ensuring that one fire would not affect all populations simultaneously. Additionally, as discussed in this rule, fires have occurred in recent times in many areas occupied by Gila trout. Thus, the risk of fire in these areas, especially one that would affect all populations, is reduced due to an overall reduction in fuel loads. Populations may still be extirpated because of forest fires, but through management activities (rescue of fish, reestablishment of populations, hatchery management) populations can be, and have been, reestablished successfully once the habitat recovers.
B. Overutilization for Commercial, Recreational, Scientific, or Educational Purposes

All stream reaches that contain Gila trout have been closed to sport fishing since the fish was listed in 1967. While some illegal fishing may take place, we believe that the amount of take is small. These are remote highelevation streams located away from roads and difficult to access. NMDGF visits the recovery streams on an annual basis and has found limited evidence of illegal fishing activity (e.g., fishing tackle has been found on a few occasions). Also, because NMDGF makes periodic visits to these streams, we believe their possible presence at unpredictable times serves as a deterrent to illegal angling activities.

The special rule (see ``Description of Proposed Special Rule'' section below) being proposed with this reclassification would enable NMDGF and the AGFD to promulgate special regulations allowing recreational fishing of Gila trout in specified waters, not including the four relict populations identified in Table 1 above. Any changes to the recreational fishing regulations will be made by the States with in collaboration with the Service. Management as a recreational species will be conducted similar to Apache trout, with angling in both recovery and enhancement waters. Enhancement waters are those managed solely for recreational purposes. Recreational management for Gila trout will be consistent with the goals of the recovery plan for the species (Service 2003). It is anticipated that implementation of the special rule will benefit the Gila trout by providing a means whereby excess Gila trout may be placed in waters that can provide a recreational benefit, thereby avoiding potential overcrowding in the designated recovery streams. Additionally, the special rule contributes to the conservation of the Gila trout through: (1) Eligibility for Federal sport fishing funds, (2) increase in the number of wild populations, (3) enhanced ability to monitor populations (e.g., creel censuses) for use in future management strategies, and (4) creation of goodwill and support in the local community. Each of these topics is discussed in detail in the ``Description of Proposed Special Rule'' section below.

A few Gila trout are removed from the wild for propagation, and some are taken for scientific or educational proposes, but the take is small and controlled through Federal and State permitting. Federal and State permitting will continue. Because of the remoteness of current and proposed recovery streams, the special regulations that will be imposed on angling, and the small amount of Gila trout collected for scientific and educational purposes, we determine that overutilization for recreational, scientific, or educational purposes is not a threat to Gila trout.

C. Disease or Predation

The carrier of bacterial kidney disease (BKD) is known to occur in trout in the upper West Fork drainage. The carrier, a bacterium (Renibacterium salmoninarum), occurs in very low amounts in brown trout populations in the upper West Fork Gila River drainage and in the Whiskey Creek population of Gila trout. The bacterium was also detected in rainbow x Gila trout hybrid populations in Iron, McKenna, and White Creeks. Although the carrier bacterium is present, there were no signs of BKD in any Gila trout populations (Service 2003). Trout populations in the Mogollon Creek drainage, McKnight Creek, Sheep Corral Canyon, and Spruce Creek all tested negative for BKD.

Whirling disease (WD) was first detected in Pennsylvania, in 1956, and was transmitted here from fish brought from Europe (Thompson et al. 1995). Myxobolus cerebralis is a parasite that penetrates through the skin or digestive tract of young fish and migrates to the spinal cartilage, where it multiplies very rapidly, putting pressure on the organ of equilibrium. This causes the fish to swim erratically (whirl) and have difficulty feeding and avoiding predators. In severe infections, the disease can cause high rates of mortality in youngof theyear fish. Water temperature, fish species and age, and dose of exposure are critical factors influencing whether infection will occur and its severity (Hedrick et al. 1999). Fish that survive until the cartilage hardens to bone can live a normal life span, but have skeletal deformities. Once a fish reaches 3 to 4 inches in length, cartilage forms into bone and the fish is no longer susceptible to effects from whirling disease. Fish can reproduce without passing the parasite to their offspring; however, when an infected fish dies, many thousands to millions of the parasite spores are released to the water. The spores can withstand freezing, desiccation, passage through the gut of mallard ducks, and can survive in a stream for many years (El Matbouli and Hoffmann 1991). Eventually, the spore is ingested by its alternate host, the common aquatic worm, Tubifex tubifex. After about 3.5 months in the gut of the worms, the spores transform into a Triactinomyon (TAM). The TAMs leave the worm and attach to the fish or they are ingested when the fish eats the worm. The spores are easily transported by animals, birds, and humans.

Salmonids native to the United States did not evolve with WD. Consequently, most native species have little or no natural resistance. Colorado River cutthroat trout and rainbow trout are very susceptible to the disease, with 85 percent mortality within 4 months of exposure to ambient levels of infectivity in the Colorado River (Thompson et al. 1999). Brown trout, native to Europe,
[[Page 24758]]
evolved with M. cerebralis, become infected but rarely suffer clinical disease. At the study site on the Colorado River, brown trout thrive, but there has been little survival beyond 1 year of age of rainbow trout since 1992 (Thompson et al. 1999). Gila trout are also vulnerable to WD (D. Shroufe, Arizona Game and Fish Department, in litt. 2003a).

There have been no documented cases of WD in the Gila River drainage in New Mexico or Arizona. Wild and hatchery populations of Gila trout tested have been negative for WD (Service 2003). Although WD is a potential threat to Gila trout, high infection rates would probably only occur where water temperatures are relatively warm and where T. tubifex is abundant. T. tubifex is the secondary host for the parasite; when T. tubifex numbers are low, the number of TAMs produced will be low, and consequently, the infection rate of Gila trout will be low. T. tubifex is an ubiquitous aquatic oligochaete (worm); however, it is most abundant in degraded aquatic habitats, particularly in areas with high sedimentation, warm water temperatures, and low dissolved oxygen. In clear coldwater streams (typical Gila trout habitat) it is present but seldom abundant. Infection rate is low at temperatures less than 10[deg]C (50[deg]F) (Thompson et al. 1999).

We determine that BKD is not a threat to the 4 original pure populations or the 10 replicated populations because of its limited distribution, low occurrence within the trout populations, and lack of any clinical evidence of the disease in Gila trout. Likewise, we determine that WD is not a threat to Gila trout because they are located in highelevation headwater streams that typically have cold water and low levels of sedimentation, which limit T. tubifex populations and infection rates from TAMs. Although Gila trout may be susceptible to infection, there has not been a documented occurrence of WD in a wild Gila trout population. Mora National Fish Hatchery and Technology Center, where Gila trout have been held, has tested negative for WD. In addition, NMDGF and AGFD are educating the public about how to prevent the spread of WD (e.g., through educational brochures and information provided with fishing regulations).

Predation of Gila trout by brown trout has been a serious problem, and continues to be a problem for fish below stream barriers. Brown trout, a nonnative salmonid, preys on Gila trout and is able to severely depress Gila trout populations. Predation threats have been addressed by chemically removing all nonnative fish and reintroducing only native species. The specific locations and timing of the potential use of chemicals in any future stream restoration projects would be made by the States in coordination with the Recovery Team. Additionally, the Gila Trout Recovery Plan provides a list of potential stream reaches that may be used for recovery purposes. Physical stream barriers, either natural waterfalls or constructed waterfalls (e.g., either composite concrete/rock or baskettype gabion) built by cooperating agencies, prevent brown trout from moving upstream and preying on Gila trout. Barrier failure is generally not considered a threat to existing Gila trout populations in New Mexico because most existing barriers are natural waterfalls. However, humanmade barriers exist on lower Little Creek, McKnight Creek, and Black Canyon. Failure of humanmade barriers would most likely result from catastrophic flooding and include scouring around barriers, undercutting, or complete removal. Brown trout and other nonnative species downstream from these barriers remain a threat.

The threat of predation by brown trout has been reduced by eliminating brown trout from streams with Gila trout populations, and by creating barriers that prevent the upstream dispersal of brown trout into areas occupied by Gila trout. Field monitoring by the Service, Forest Service, AGFD, and the NMDGF of Gila trout provides a means to detect the introduction of brown trout into a Gila trout population, and, once detected the nonnatives are removed (Service 2004). Each population is monitored at least once every 3 years. Monitoring may occur more, often depending upon the situation, such as additional surveys due to the occurrence of wildfire. Annual monitoring using electrofishing is not undertaken due to potential sampling impacts from electrofishing. The Emergency Plan provides further information on the procedures for detecting and addressing the threat of nonnatives (Service 2004).

D. The Inadequacy of Existing Regulatory Mechanisms

Before the Gila trout was federally listed as endangered (1967), the species had no legal protection. Upon being listed under the Act, the Gila trout immediately benefited from a Federal regulatory framework that provided protection and enhancement of the populations in three ways. First, take was prohibited. Take is defined under the Act to include killing, harassing, harming, capturing, or collecting individuals or attempting to do any of these things. Habitat destruction or degradation is also prohibited if such activities harm individuals of the species. Second, section 7 of the Act requires that Federal agencies consult with the Service to ensure that their actions will not likely jeopardize the continued existence of the species. Third, once a species is listed, the Service is required to complete a recovery plan and make timely revisions, if needed. Thus, listing the species provided recognition, protection, and prohibitions against certain practices (such as take), facilitated habitat protection, and stimulated recovery actions.

Subsequent to the Federal listing action, the States of New Mexico and Arizona officially recognized the declining status of the species. Arizona designated the Gila trout as an endangered species in 1988, which includes species that are known or suspected to have been extirpated from Arizona but that still exist elsewhere. New Mexico designated the Gila trout as an endangered species (Group 1) on January 24, 1975 (NM State Game Commission Regulation No. 663) under authority of the Wildlife Conservation Act. Group 1 species are those whose prospects of survival or recruitment in New Mexico are in jeopardy. The designation provides the protection of the New Mexico Wildlife Conservation Act (Sections 17237 through 17218 NMSA 1978) and prohibits taking of such species except under a scientific collecting permit. New Mexico also has a limited ability to protect the species' habitat through the Habitat Protection Act (Sections 1731 through 17 311) through water pollution legislation, and tangentially through a provision that makes it illegal to dewater areas used by game fish (Section 17114). Take of Gila trout in Arizona is prohibited through State statute (Arizona Revised Statute Title 17) and Commission Order (Commission Order 40). We do not expect any changes in the current State protections provided to the Gila trout as a result of this rule. However, if our proposed special rule is finalized, the States of Arizona and New Mexico will likely be adopting regulations to allow for recreational fishing as described in the ``Description of the Proposed Special Rule'' section below.

We determine that because of the protection that would be provided from Federal listing as a threatened species, along with this proposed special rule, State regulatory protection, and habitat protection provided by the National Forests, there are adequate regulatory mechanisms to protect and enhance Gila trout populations and their habitat.
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Many of these protective regulations, conservation measures, and recovery actions have substantially improved the status of the Gila trout.
E. Other Natural or Manmade Factors Affecting Its Continued Existence

When the Gila trout was listed as endangered, the most important reason for the species' decline was hybridization and competition with and/or predation by nonnative salmonids (52 FR 37424). Uncontrolled angling depleted some populations of Gila trout, which in turn encouraged stocking of hatcheryraised, nonnative species (Miller 1950; Propst 1994). Due to declining native fish populations, the NMDGF propagated and stocked Gila trout, rainbow trout, cutthroat trout, and brown trout during the early 1900s to improve angler success. Gila trout were propagated from 1923 to 1935, at the Jenks Cabin Hatchery in the Gila Wilderness, but the program was abandoned because of the hatchery's poor accessibility and low productivity (Service 1984). After early stocking programs were discontinued, the nonnative trout species persisted and seriously threatened the genetic purity and survival of the few remaining populations of Gila trout. Recent efforts to recover the species have included eliminating nonnative salmonids from the species historic habitat through piscicide (fishkilling), mechanical removal, and construction of waterfall barriers to prevent their reinvasion. Currently, 12 viable populations of Gila trout exist in the absence of nonnative salmonids.

We have determined that the threats posed by nonnative fish are reduced because nonnative trout are not present in the streams with original pure or replicated populations of Gila trout. Barriers are present to prevent nonnative trout from dispersing into areas occupied by pure Gila trout populations. Drought, wildfire, and floods remain as threats. However, conditions are monitored and fish can be rescued from streams threatened by drying, fires, floods, or barrier failure, if necessary (Service 2004). As explained in the Emergency Plan, these remote areas may be accessed through helicopter or use of horses and mules, depending upon the urgency of the situation. Flooding that occurs in an undisturbed watershed is not considered a threat to Gila trout. However, flooding that occurs after a severe fire is a threat. Service personnel monitor fires and the potential for flooding, and rescue fish from streams that are in danger of flash floods (Service 2004). Rescued fish may be used in broodstock development, may be introduced into other suitable streams, or they can be placed back into their stream of origin once the habitat conditions are suitable. However, it may take many years for the habitat to recover to the point that it is suitable for trout again.

Summary

We believe that reclassifying the Gila trout from endangered to threatened status with a special rule is consistent with the Act, and that the special rule will further the conservation and recovery of this species. See the ``Description of the Proposed Special Rule'' section below for an explanation of the conservation benefits of the proposed special rule. Threatened status is appropriate because the number of populations has increased from 4 to 12 since recovery efforts began and the threats affecting the species have been reduced or eliminated. Additionally, as noted above, the wild populations of Gila trout were estimated to be fewer than 10,000 fish greater than age 1 in 1992. In 2001, almost 10 years later, the population in New Mexico had increased significantly and was estimated to be 37,000 fish (Brown et al. 2001). Three of the four original pure population lines are protected and replicated in 100 km (62 mi) of stream, each replicate is geographically separate from its remnant population, and an Emergency Plan was developed and has been implemented in 2002 and 2003 (Service 2004), and will continue to be implemented as necessary. A copy of the Emergency Plan is available by contacting the New Mexico Fishery Resources Office (see ADDRESSES section). We have determined that the Gila trout is no longer in danger of extinction throughout all or a significant portion of its range and therefore no longer meets the definition of endangered.

Threatened status is appropriate for the Gila trout because although the major threats have been r

FOR FURTHER INFORMATION CONTACT

Joy Nicholopoulos, State Supervisor, New Mexico Ecological Services Field Office (see ADDRESSES above).

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