98-7997. Endangered and Threatened Wildlife and Plants; Proposed Rule To List the Devils River Minnow (Dionda diaboli) as Endangered  

  • [Federal Register Volume 63, Number 59 (Friday, March 27, 1998)]
    [Proposed Rules]
    [Pages 14885-14892]
    From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
    [FR Doc No: 98-7997]
    
    
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    DEPARTMENT OF THE INTERIOR
    
    Fish and Wildlife Service
    
    50 CFR Part 17
    
    RIN 1018-AE86
    
    
    Endangered and Threatened Wildlife and Plants; Proposed Rule To 
    List the Devils River Minnow (Dionda diaboli) as Endangered
    
    AGENCY: Fish and Wildlife Service, Interior.
    
    
    [[Page 14886]]
    
    
    ACTION: Proposed rule.
    
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    SUMMARY: The U.S. Fish and Wildlife Service (Service) proposes to list 
    the Devils River minnow (Dionda diaboli) as an endangered species under 
    authority of the Endangered Species Act of 1973, as amended (Act). The 
    current range of the Devils River minnow is limited to three stream 
    systems in Val Verde and Kinney counties, Texas, and one drainage in 
    Coahuila, Mexico. The species' range has been significantly contracted 
    and fragmented. In addition, the numbers of Devils River minnows 
    collected during fish surveys has declined dramatically over the past 
    25 years; the species has declined from one of the most abundant fish 
    to one of the least abundant. Based on the current information, the 
    decline of the species in both distribution and abundance may be 
    attributed in large part to the effects of habitat loss and 
    modification and possibly predation by smallmouth bass (Micropterus 
    dolomieu), an introduced game fish. This proposal, if made final, will 
    implement Federal protection provided by the Act for the Devils River 
    minnow.
    
    DATES: Comments from all interested parties must be received by July 
    27, 1998. Public hearing requests must be received by May 11, 1998.
    
    ADDRESSES: Comments and materials concerning this proposal should be 
    sent to the Field Supervisor, Austin Ecological Services Field Office, 
    U.S. Fish and Wildlife Service, 10711 Burnet Road, Suite 200, Austin, 
    Texas, 78758. Comments and materials received will be available for 
    public inspection, by appointment, during normal business hours at the 
    above address.
    
    FOR FURTHER INFORMATION CONTACT: Nathan Allan, Fish and Wildlife 
    Biologist (see ADDRESSES section) (telephone 512/490-0057; facsimile 
    512/490-0974).
    
    SUPPLEMENTARY INFORMATION:
    
    Background
    
        The Devils River minnow (Dionda diaboli Hubbs and Brown) is 
    classified in the Cyprinidae (Minnow) family. It was first collected 
    from Las Moras Creek, near Brackettville, Texas, on April 14, 1951. The 
    species was formally described by Hubbs and Brown (1956) from specimens 
    collected in the Devils River; the holotype locality being Devils River 
    at Baker's Crossing. The species occurs with Dionda argentosa 
    (manantial roundnose minnow) and is also similar to Dionda episcopa 
    (roundnose minnow). Devils River minnow is recognized as a distinct 
    species by the American Fisheries Society (Robins et al. 1991) based on 
    morphological characteristics (Hubbs and Brown 1956), genetic markers 
    (Mayden et al. 1992) and chromosome differences (Gold et al. 1992).
        The Devils River minnow is a small fish, with adults reaching sizes 
    of 25-53 millimeters (mm) (1.0-2.1 inches (in)) standard length. The 
    fish has a wedge-shaped caudal spot and pronounced lateral stripe with 
    double dashes extending through the eye to the snout but not reaching 
    the lower lip. The species has a narrow head with prominent dark 
    markings on scale pockets above the lateral line that produce a cross-
    hatched appearance when viewed from the top (Hubbs and Brown 1956).
        No information is available on life history characteristics, 
    feeding patterns, or reproductive behaviors of this species. However, 
    based on the extended intestinal tract, species of the genus Dionda are 
    considered to feed primarily on algae. Dionda episcopa have been 
    observed to be broadcast spawners with nonadhesive eggs that sink to 
    the substrate (Johnston and Page 1992).
        General habitat associations for Devils River minnow have been 
    described as channels of fast-flowing, spring-fed waters over gravel 
    substrates (Harrell 1978). Although the species is closely associated 
    with spring systems, it most often occurs where spring flow enters a 
    stream, rather than in the spring outflow itself (Hubbs and Garrett 
    1990). The species is adapted to the hydrologic variations inherent in 
    desert river systems (Harrell 1978), characterized by extended droughts 
    and extreme flash floods (USGS 1989).
        The Devils River minnow is part of a unique fish fauna in west 
    Texas streams where a mixture of fishes occur, including Mexican 
    peripherals, local endemics, and widespread North American fishes 
    (Hubbs 1957). About half of the native fishes of the Chihuahuan Desert 
    of Mexico and Texas are considered threatened by Hubbs (1990) and at 
    least four species have been documented to already be extinct (Miller 
    et al. 1989), primarily due to habitat destruction and introduced 
    species.
        The Devils River minnow is native to tributary streams of the Rio 
    Grande River in Val Verde and Kinney counties, Texas, and Coahuila, 
    Mexico. The known historic range of the species is based on collections 
    from the 1950s and 1970s and includes--the Devils River from Beaver 
    Lake downstream to near its confluence with the Rio Grande; San Felipe 
    Creek from the springs in the headwaters to springs in Del Rio; 
    Sycamore Creek, in Kinney County; Las Moras Creek near Brackettville; 
    and Rio Sabinas, Rio San Carlos, and Rio Alamo from the Rio Salado 
    drainage in northern Mexico (Brown 1955; Hubbs and Brown 1956; Robinson 
    1959; Harrell 1978; Smith and Miller 1986; Garrett et al. 1992). 
    Despite numerous collection efforts, the species has never been 
    reported from the mainstem Rio Grande, the Rio Conchos drainage, or 
    tributary streams other than those listed above. The range of the 
    species prior to 1951 is unknown.
        The current distribution of Devils River minnow in Texas was 
    described by Garrett et al. (1992). This study documented the presence 
    of the species in 1989 at two sites on the Devils River, two sites on 
    San Felipe Creek, and one site on Sycamore Creek. Garrett et al. (1992) 
    showed that Devils River minnow was very rare throughout its range in 
    1989 compared to past collections. At 24 sampling locations within the 
    historic range, a total of only 7 individuals were collected from 5 
    sites. In addition to declines in the Devils River minnow populations, 
    Garrett et al. (1992) also observed a general shift in community 
    structure toward fishes that tend to occupy quiet water or pool 
    habitat, conditions that are often limited in flowing spring runs. The 
    authors hypothesized that this shift was the result of reduced stream 
    flows from drought, exacerbated by human modification to stream 
    habitats, especially in Sycamore and Las Moras creeks.
        No published information has been found on the status of the Devils 
    River minnow in Mexico. A review of museum records indicates the 
    species may now occur in only two localities in Mexico. Populations 
    there appear to be very depressed and face significant threats from 
    industrial development (Contreras and Lozano 1994; S. Contreras-B., 
    University of Nuevo Leon, in litt. 1997). Throughout the region of 
    northern Mexico, fish species are severely threatened with habitat loss 
    and modification. Of an approximate 200 species that may occur in the 
    region, 135 are considered threatened (Williams et al. 1989; Contreras 
    and Lozano 1994) and 15 are thought to already be extinct (Miller et 
    al. 1989; Contreras and Lozano 1994).
        The region of Texas where the Devils River minnow occurs is semi-
    arid, receiving an average of about 46 centimeters (cm) (18 in) of 
    rainfall annually. Spring-fed streams of west Texas flow southerly 
    through rocky, limestone soils and shrubby vegetation characteristic of 
    desert hill country. The aquifer that sustains spring flows within
    
    [[Page 14887]]
    
    the range of the Devils River minnow is the Edwards-Trinity (Plateau) 
    Aquifer. This major aquifer produces the largest number of springs in 
    Texas (Brune 1975). The contributing recharge area for springs on the 
    Devils River and San Felipe Creek is suspected to include a large area 
    as far north as Sheffield in Pecos County and Eldorado in Schleicher 
    County, although the subsurface hydrogeomorphology of the region is not 
    well-defined (Brune 1981). The flow from springs tends to fluctuate 
    considerably, depending on the amount of rainfall, recharge, and water 
    in storage in the underground reservoirs. Conservation of this 
    groundwater supply is essential for the continued existence of the 
    Devils River minnow.
        Areas where the Devils River minnow occurs are mostly in private 
    ownership. Exceptions include the Devils River State Natural Area, 
    owned by the Texas Parks and Wildlife Department (TPWD) (Baxter 1993), 
    and land adjoining portions of San Felipe Creek, owned by the City of 
    Del Rio (population of about 38,000). One important private holding is 
    the Dolan Falls Preserve, owned by The Nature Conservancy (Baxter 
    1993). Primary land uses are cattle, sheep, and goat ranching. 
    Generally, these areas are very remote with little human development, 
    beyond those to support ranching operations. Primary communities within 
    the Devils River watershed are Ozona in Crockett County and Sonora in 
    Sutton County (each with a population of less than 5,000), in the upper 
    portion of the drainage where flows in the Devils River are 
    intermittent. The middle and lower portions of the Devils River are 
    popular for recreational fishing and canoeing (Gough 1993), although 
    public access is limited.
        The Devils River minnow is currently listed as a threatened species 
    by the State of Texas, the Texas Organization for Endangered Species 
    (Hubbs et al. 1991), and the Endangered Species Committee of the 
    American Fisheries Society (Williams et al. 1989).
    
    Previous Federal Action
    
        On August 15, 1978, the Service published a proposed rule (43 FR 
    36117) to list the Devils River minnow as a threatened species and to 
    designate critical habitat. On March 6, 1979, the Service published a 
    notice (44 FR 12382) to withdraw the critical habitat portion of the 
    proposal in order to meet requirements set forth in the Endangered 
    Species Act Amendments of 1978 (Public Law 95-632, 92 Stat. 3751). The 
    Service reproposed the designation of critical habitat for the Devils 
    River minnow on May 16, 1980 (45 FR 32348). A notice of public hearing 
    was published on July 9, 1980 (45 FR 46141), and the public hearing was 
    held on July 23, 1980, in Del Rio, Texas. The Service gave notice that 
    the listing and critical habitat proposals were withdrawn on September 
    30, 1980 (45 FR 64853), because the 2-year time limit on the proposal 
    had expired.
        The Service included the Devils River minnow as a category 2 
    candidate species in Notices of Review published December 30, 1982 (47 
    FR 38454), September 18, 1985 (50 FR 37958), and January 6, 1989 (54 FR 
    554). Category 2 taxa were those that the Service believed may be 
    eligible for threatened or endangered status, but for which the 
    available biological information in possession of the Service was 
    insufficient to support listing the species. However, new information 
    obtained in 1989 (and later published as Garrett et al. 1992) provided 
    a basis for including the Devils River minnow as a category 1 candidate 
    in Notices of Review published November 21, 1991 (56 FR 58804), and 
    November 15, 1994 (59 FR 58982). Category 1 taxa were those for which 
    the Service had substantial biological information on hand to support 
    proposing to list the species as threatened or endangered.
        As announced in a notice published in the February 28, 1996, 
    Federal Register (61 FR 7596), the designation of multiple categories 
    of candidates has been discontinued, and only former category 1 species 
    are now recognized as candidates for listing purposes. The Devils River 
    minnow remained a candidate species with a listing priority of 2 in 
    Notices of Review published February 28, 1996 (61 FR 7596), and 
    September 19, 1997 (62 FR 49398). The listing priority numbers for 
    candidate taxa range from 1 (highest priority) to 12 (lowest priority) 
    and are assigned by the Service based on the immediacy and magnitude of 
    threats, as well as taxonomic status (48 FR 43098).
    
    Summary of Factors Affecting the Species
    
        Section 4(a)(1) of the Act (16 U.S.C. 1531 et seq.) and regulations 
    (50 CFR part 424) promulgated to implement the listing provisions of 
    the Act set forth the procedures for adding species to the Federal 
    lists. A species may be determined to be an endangered or threatened 
    species due to one or more of the five factors described in section 
    4(a)(1). These factors and their application to the Devils River minnow 
    (Dionda diaboli) are as follows:
    
    A. The present or threatened destruction, modification, or curtailment 
    of its habitat or range.
    
    (1.) Devils River
        The Devils River constitutes the largest segment of the documented 
    range of the Devils River minnow. Over 40 percent of the total length 
    of the Devils River has been lost as potential habitat, representing a 
    contraction of the range from the northern extent of the distribution 
    of the species. The Devils River from Beaver Springs to its confluence 
    with the Rio Grande is about 127 river-kilometers(km) (79 river-
    miles(mi)) long. The lower 29 km, downstream of Big Satan Creek, is 
    inundated by Amistad Reservoir. The uppermost 26 km, between Pecan 
    Springs and Beaver Springs, can no longer be considered suitable 
    habitat because of the loss of permanent flows.
        The most significant loss of Devils River minnow habitat occurred 
    on the Devils River with the impoundment of Amistad Reservoir in 1968. 
    Backwaters from Amistad Dam inundated the natural stream habitats 
    (about 29 km), transforming the area from a riverine to lake 
    environment. The area is no longer suitable for most native fishes, 
    including Devils River minnow. Before construction of Amistad Dam, two 
    smaller dams (Devils Lake and Wall Lake) were built in the 1920's in 
    this lower portion of the stream. However, spring run habitat remained 
    and Devils River minnow was collected there in 1953 and 1954. Amistad 
    Reservoir, however, inundated these springs, eliminating the natural 
    environment and suitable habitat for native fish. Also, the 
    construction of the dam created a physical barrier to fish movement 
    that permanently separated the Devils River population of the species 
    from other populations.
        In addition to habitat loss in the lower Devils River due to 
    impoundment, habitat for the species has been lost from the lack of 
    permanent spring flows in the upstream portion (about 26 km) of the 
    river (Dietz 1955, Brune 1975, Harrell 1978). These springs 
    historically provided a pristine source of significant flowing water. 
    Brune (1981) indicates that agricultural land use practices both within 
    and north of the watershed may affect aquifer levels and account for a 
    lack of permanent flows from the northern-most springs. Heavy well 
    pumping from groundwater reserves for irrigation (Dietz 1955) and long 
    term overgrazing (that reduces recharge and enhances runoff) have been 
    cited as possible causes for decreased spring flows in the upper Devils 
    River (Brune 1981). Springs on the Devils River
    
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    (upstream of Pecan Springs) that no longer support permanent discharges 
    include Beaver, Juno, Headwater, Stein, and San Pedro springs (Brune 
    1981).
        Continued decline of permanent discharge from springs is a 
    significant threat to Devils River minnow in the middle segment of the 
    Devils River. This threat can be the result of drought and/or human 
    activities that withdraw groundwater or prevent recharge. The remaining 
    central portion of the Devils River continues to flow naturally, and 
    has been referred to as one of the most pristine rivers in Texas. 
    Because of large groundwater reservoirs that support the remaining 
    spring systems, the river maintains a substantial perennial flow.
        Historic stream flow analysis, however, indicates decreasing base 
    flows during the 1960's that were independent of precipitation levels 
    (suggesting human influences). Drought can further aggravate spring 
    flow declines (Garrett 1992). Declining trends of stream flow during 
    the 1950's and 1980's track a decrease in precipitation in the region, 
    suggesting the effects of drought (USGS 1989).
        When spring flows become seasonally intermittent, fish populations 
    are unable to use the stream to fulfill their life history 
    requirements. Declines in base flow of streams also affect fish 
    populations by reducing the total available habitat and thereby 
    intensifying competitive and predatory interactions. For Devils River 
    minnow, decreased instream flows may lead to a population decline due 
    to exclusion from preferred habitats and increased mortality from 
    predation.
        Using relative abundance as an indicator, the Devils River minnow 
    has decreased in the Devils River over time. The Devils River minnow 
    was the fifth most abundant species of 18 species collected in 1953 at 
    Bakers Crossing (Brown 1955); the sixth most abundant of 23 species in 
    the river in 1974 (Harrell 1978); and one of the least abundant of 16 
    species in 1989 (Garrett et al. 1992). Recent information from Cantu 
    and Winemiller (1997) indicates that the species was still present in 
    the Devils River at the confluence with Dolan Falls in 1994, but only 
    in low numbers (thirteenth most abundant of 27 species). The four 
    collections by Cantu and Winemiller (1997) were extensive surveys over 
    1 year at the one site near Dolan Falls. Even with this increased 
    effort, only 28 individuals of Devils River minnow, out of 4,470 total 
    fish, were documented.
        New information on the distribution and abundance of Devils River 
    minnow in the Devils River and San Felipe Creek was obtained from 
    surveys conducted in November 1997 by the TPWD. No Devils River minnow 
    were collected from several locations on the Devils River from Pecan 
    Springs downstream to Finegan Springs, just above Dolan Falls (Gary 
    Garrett, TPWD, in litt. 1997). This indicates that, if the fish still 
    persists in the Devils River, it is very rare.
        The drastic decline in abundance within the Devils River can best 
    be documented from collections at the site at Baker's Crossing. Over 60 
    individuals were collected there in 1953, only one was collected in 
    1989, and none were collected in 1997.
    (2.) San Felipe Creek
        San Felipe Creek constitutes the second largest segment of 
    remaining habitat for Devils River minnow in Texas. Devils River minnow 
    previously occurred in two areas on this stream. The upper area is 
    associated with a series of headwater springs several miles upstream of 
    the City of Del Rio and the lower area is associated with two large 
    springs in Del Rio.
        In 1979, Devils River minnow made up about 2 percent of all 
    collections (total of 3,458 fish), and was the seventh most abundant of 
    16 species in the headwater springs in the upper portion of San Felipe 
    Creek. In 1989, no Devils River minnow were collected from this site 
    (Garrett et al. 1992). No known collections have been made in this area 
    since 1989. This area of San Felipe Creek (upstream of Del Rio) is 
    privately owned and no information is available to discern why the 
    populations of Devils River minnow in this area have significantly 
    declined.
        In San Felipe Springs (in Del Rio) in 1989, the fish was very rare 
    (less than 1 percent of 1,651 fish collected, and the tenth most 
    abundant of 12 species collected) (Garrett et al. 1992). Data from 1997 
    suggest that the Devils River minnow is common in the San Felipe 
    Springs and the urban section of the creek (about 50 individuals were 
    collected for captive study) (Gary Garrett, TPWD, in litt. 1997).
        The San Felipe Springs are located within the City of Del Rio and 
    may be threatened with future habitat changes from continued urban 
    development. Brune (1975) lists San Felipe Springs as one of the four 
    largest springs in Texas. The City draws water directly from the 
    springs which are the sole source of the City's municipal water supply. 
    The expected population growth of Del Rio is projected to be low (0.5 
    to 1 percent annual growth). With some water conservation measures in 
    place to reduce per capita water use, the City could reduce its water 
    consumption in coming decades. However, any future declines in spring 
    flows due to increased withdrawals could affect the Devils River minnow 
    population in this location. Presently, Amistad Reservoir is thought to 
    increase spring flows from San Felipe Springs because the pool 
    elevation of the reservoir is often higher than that of the spring 
    outlet. This situation places hydrostatic pressure on San Felipe 
    Springs through inundated spring openings within the reservoir (Brune 
    1981).
        Water quality and contamination are constant threats to the 
    population in San Felipe Creek because of the urban setting. Recent 
    studies by the Texas Natural Resource Conservation Commission (TNRCC) 
    (1994) found elevated levels of nitrates, phosphates and 
    orthophosphates in San Felipe Creek, indicating potential water quality 
    problems. Land uses in the immediate area of the springs, such as 
    runoff from the municipal golf course near the spring, may be 
    contributing to these conditions. Other threats from catastrophic 
    events such as contaminant spills could affect the species.
        Based on the current abundance of the Devils River minnow in San 
    Felipe Creek, it appears that existing practices that could impact the 
    aquatic habitat are not yet serious enough to significantly reduce the 
    local population. Aquatic habitat conservation measures (such as water 
    use conservation and water quality protection) in this section of San 
    Felipe Creek could help ensure survival of the species there.
    (3.) Sycamore Creek
        Sycamore Creek constitutes a relatively small portion of the range 
    of the species. There is only one published account of fishes in this 
    stream from one site, at the State Highway 277 crossing near the Rio 
    Grande River (Garrett et al. 1992), although Harrell (1980) references 
    the species' occurrence there. Garrett et al. (1992) found very few 
    individuals at this location. Sycamore Creek is an ungaged stream, and 
    there is little information available on habitat conditions. However, 
    the Devils River minnow in this stream is evidently very rare and faces 
    increased risks for extirpation because of the apparent small 
    population size. Devils River minnow in Sycamore Creek likely face 
    potential threats from decreasing spring and stream flows due to 
    groundwater withdrawals and some land use practices in the watershed.
    (4.) Las Moras Creek
        Las Moras Creek represents the eastern extent of the range of the 
    species. Although the populations there may have been restricted to the 
    spring
    
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    area in Brackettville, the number of fish in historic collections was 
    relatively large (54 individuals were collected in 1953) (Hubbs and 
    Brown 1956). The natural spring system in Brackettville that supports 
    Las Moras Creek is the location of the earliest collection of Devils 
    River minnow. The species has not been collected from these springs 
    since the 1950s and is believed to be extirpated from that stream, 
    based on several sampling efforts in the late 1970's and 1980's (Smith 
    and Miller 1986; Hubbs et al. 1991; Garrett et al. 1992).
        Habitat for the Devils River minnow was lost when the spring was 
    altered by damming the outflow and removing streambank vegetation to 
    create a recreational swimming pool. Garrett et al. (1992) reported 
    that the creek smelled of chlorine, indicating that the swimming pool 
    may be maintained with chlorination (a toxin to fish). Garrett et al. 
    1992 also indicates that spring flow has been drastically reduced by 
    drought and diversion of water for human consumption. This combination 
    of habitat loss and alteration and the resulting water quality problems 
    appears to be the most likely cause for the apparent extirpation of the 
    species from Las Moras Creek.
    (5.) Rio Salado
        The populations of Devils River minnow in the Rio Salado Drainage 
    of northern Mexico represent a critical portion of the range. These 
    streams are southern tributaries of the Rio Grande and are 
    geographically distinct from the tributaries where the fish occurs in 
    Texas. Garrett et al. (1992) cites that the Devils River minnow occurs 
    in low numbers in the Rio San Carlos and Rio Sabinas. The species may 
    also occur in the Rio Alamo (S. Contreras-B., University of Nuevo Leon, 
    in litt. 1997).
        The condition of aquatic habitats in the Rio Salado drainage in 
    Mexico is extremely poor. Contreras and Lozano (1994) report that 
    aquatic ecosystems in this region of Mexico face significant threats 
    due to groundwater and surface water withdrawals, as well as air and 
    water pollution. Watersheds in northern Mexico have been heavily 
    impacted by land uses and industrial development (S. Contreras-B., 
    University of Nuevo Leon, in litt. 1997). The Rio Sabinas, in 
    particular, has been noted for decreasing flows; and spring systems 
    within Coahuila have been extensively exploited (Contreras and Lozano 
    1994).
    (6.) Range-Wide
        Habitat loss and modification throughout a significant portion of 
    the range of the Devils River minnow has resulted in both the 
    fragmentation and contraction of the range of the species. The previous 
    occurrences of known populations of Devils River minnow in Texas can be 
    grouped into nine geographic areas, primarily associated with spring 
    systems: five areas in the Devils River (lower Devils River, Dolan 
    Falls, Baker's Crossing, Pecan Springs, Juno to Beaver Lake); two areas 
    in San Felipe Creek (headwater springs and Del Rio); one area in 
    Sycamore Creek; and one area in Las Moras Creek. Of these nine areas, 
    the best available information indicates that a viable population may 
    exist only in San Felipe Creek in Del Rio. The known existence of only 
    one viable population located in an urban setting makes the threat of 
    extinction of the species within the U.S. very high. Although detailed 
    information is limited regarding the status of the species in Mexico, 
    its condition there is likely at least to be threatened.
        The construction of Amistad Dam has separated the two primary 
    populations of Devils River minnow in Texas (Devils River and San 
    Felipe Creek) and assured they will be permanently isolated from one 
    another. This population fragmentation has significant conservation 
    implications (Gilpin 1987). Determining and monitoring the genetic 
    structure of the different Devils River minnow populations will be 
    needed to ensure the necessary genetic variation within and among 
    populations is not lost (Meffe 1986; Minckley et al. 1991).
    
    B. Overutilization for Commercial, Recreational, Scientific, or 
    Educational Purposes
    
        Overutilization is not considered a significant threat to the 
    Devils River minnow. However, there is a potential for impacts should 
    this species be harvested as a baitfish (either commercially or non-
    commercially).
    
    C. Disease or Predation
    
        The Devils River minnow may be affected by the presence of 
    introduced fishes within its range. Of special concern is the threat of 
    predation by smallmouth bass (Micropterus dolomieu), a game fish 
    introduced to Amistad Reservoir in about 1975. The smallmouth bass is 
    native to eastern North America but has been widely introduced as a 
    sport fish to reservoirs and streams outside its natural range. It is 
    believed smallmouth bass gained access to the upper portions of the 
    Devils River (upstream of Dolan Falls) in the early to mid-1980's (Gary 
    Garrett, TPWD, pers. comm. 1997). This species is now the dominant 
    predator in the fish community of the Devils River. The TPWD is 
    currently managing the Devils River as a trophy smallmouth bass 
    fishery.
        The Devils River minnow evolved in the presence of native 
    piscivores such as channel catfish (Ictalurus punctatus) and largemouth 
    bass (Micropterus salmoides) and is adapted to persist with these 
    species. However, smallmouth bass are not native, are aggressive 
    predators, and are known to impact other native fish communities 
    (Taylor et al. 1984, Moyle 1994). The Devils River minnow falls within 
    the size class of small fishes that are susceptible to predation by 
    smallmouth bass. The scarcity of Devils River minnow in the Devils 
    River (where smallmouth bass are prominent) and the abundance of Devils 
    River minnow in San Felipe Creek (where smallmouth bass are not known 
    to occur) provides circumstantial evidence of the likely impacts of 
    this introduced predator. The establishment of smallmouth bass in San 
    Felipe Creek is another potential threat to that Devils River minnow 
    population.
        The release (intentional or unintentional) of other minnows into 
    areas inhabited by Devils River minnow is another potential threat. 
    Live bait fish are commonly discarded by anglers resulting in 
    introductions of nonnative species. This situation has occurred in many 
    streams in the southwestern U.S. with considerable impacts to the 
    native fish community (Moyle 1994). Exotic fishes from aquariums can 
    also be introduced into local waters. Currently, only a small number of 
    introduced fishes occur within the range of the Devils River minnow, 
    but the potential for bait bucket introductions is high because of the 
    number of anglers on the Devils River. Threats to the populations of 
    Devils River minnow from possible introduction and establishment of 
    nonnative fishes include diseases, parasites, competition for food and 
    space, and hybridization.
    
    D. The Inadequacy of Existing Regulatory Mechanisms
    
        The Devils River minnow is listed as a threatened species by the 
    State of Texas. This provides some protection from collecting, as a 
    permit is required to collect listed species in Texas. However, there 
    is no State or local mechanism to protect habitat for the conservation 
    of the species. In addition, limited regulations exist to prevent 
    unintentional releases of exotic species by the baitfish industry and 
    anglers.
        Limited State regulations exist that serve to protect instream 
    flows for surface water rights and water quality for wildlife and human 
    uses. However,
    
    [[Page 14890]]
    
    these regulations were not designed to conserve habitat for native 
    fishes and currently no minimum instream flows are required on streams 
    where Devils River minnow occur. Surface water rights along the Rio 
    Grande in Texas and its U.S. tributaries are administered by the State 
    of Texas. Groundwater withdrawals that could be affecting stream flows 
    within the range of the Devils River minnow are unregulated. Texas 
    courts have held that, with few exceptions, landowners have the right 
    to take all the water that can be captured under their land (right of 
    capture). Therefore, there is little opportunity to protect groundwater 
    reserves within existing regulations.
        State Water Quality Standards, though primarily concerned with 
    protecting human health, may provide some protection to the Devils 
    River minnow and its habitat. The classification of the Devils River 
    and San Felipe Creek under the Texas Surface Water Quality Standards 
    requires maintenance of existing water quality. Sycamore and Las Moras 
    Creeks are not classified under these standards
    
    E. Other Natural or Manmade Factors Affecting Its Continued Existence.
    
        The destruction of habitat throughout the range of the Devils River 
    minnow has reduced the number of viable populations of the species, 
    perhaps down to as few as one. The restricted range makes the species 
    especially vulnerable to extinction. The Devils River minnow is 
    currently known to be common in only one location, San Felipe Creek in 
    Del Rio, and this population is threatened due to its proximity to the 
    urban environment.
        Populations of Devils River minnow in Sycamore Creek, and possibly 
    the Devils River, may have so few individuals that they may no longer 
    constitute viable populations (Caughley and Gunn 1996). Small 
    populations can lead to genetic erosion through inbreeding and are more 
    vulnerable to loss from random natural events than larger populations 
    (Meffe 1986).
        The overall decline in abundance of Devils River minnow is likely 
    the result of several cumulative factors. For example, subtle changes 
    in stream flows could produce small shifts in habitat use that make the 
    species more vulnerable to competition and predation by native 
    predators and nonnative smallmouth bass. In addition, long-term drought 
    can have a major effect on the habitat of the species, particularly 
    when combined with impacts of human water use. This species has adapted 
    to the historic natural climatic variations (such as large floods and 
    prolonged droughts). However, in conjunction with other threats to the 
    species (primarily existing habitat loss and exotic predators), a 
    drought could significantly increase the threat of extinction. The use 
    of water supplies for human needs (municipal or agricultural) serves to 
    worsen the effects of drought on the natural environment.
        The Service has carefully assessed the best scientific and 
    commercial information available regarding the past, present, and 
    future threats faced by this species in determining to propose this 
    rule. Based on this evaluation, the preferred action is to list the 
    Devils River minnow as endangered. The species currently inhabits a 
    very limited range and the best scientific information available 
    indicates a decline in abundance throughout the range of the species. 
    The species is in danger of becoming extinct in the foreseeable future 
    throughout all or a significant portion of its range. Threatened status 
    would not accurately reflect the vulnerability of the species due to 
    its restricted range and low numbers. Critical habitat is not being 
    proposed for the reasons discussed below.
    
    Critical Habitat
    
        Critical habitat is defined in section 3 of the Act as: (i) The 
    specific areas within the geographical area occupied by a species, at 
    the time it is listed in accordance with the Act, on which are found 
    those physical or biological features (I) essential to the conservation 
    of the species and (II) that may require special management 
    considerations or protection and; (ii) specific areas outside the 
    geographical area occupied by a species at the time it is listed, upon 
    a determination that such areas are essential for the conservation of 
    the species. ``Conservation'' means the use of all methods and 
    procedures needed to bring the species to the point at which listing 
    under the Act is no longer necessary.
        Section 4(a)(3) of the Act and implementing regulations (50 CFR 
    424.12) require that, to the maximum extent prudent and determinable, 
    the Secretary designate critical habitat at the time the species is 
    determined to be endangered or threatened. Service regulations (50 CFR 
    424.12(a)) state that designation of critical habitat is not prudent 
    when one or both of the following situations exist: (1) The species is 
    threatened by taking or other human activity, and identification of 
    critical habitat can be expected to increase the degree of such threat 
    to the species; or (2) such designation of critical habitat would not 
    be beneficial to the species.
        The Service finds that the designation of critical habitat for the 
    Devils River minnow is not prudent due to lack of benefit. The section 
    7 prohibitions against adverse modification of critical habitat apply 
    to Federal actions only (see Available Conservation Measures section). 
    The watersheds in the U.S. in which the Devils River minnow occurs are 
    almost entirely in private ownership, and no significant Federal 
    actions affecting the species' habitat are likely to occur in the area. 
    Therefore, the designation of critical habitat would provide no benefit 
    to the species.
        In addition, any Federal action which would cause adverse 
    modification of critical habitat for the Devils River Minnow likely 
    would also cause jeopardy. Under section 7, actions funded, authorized, 
    and carried out by Federal agencies may not jeopardize the continued 
    existence of a species or result in the destruction or adverse 
    modification of critical habitat. To ``jeopardize the continued 
    existence'' of a species is defined as an action that appreciably 
    reduces the likelihood of its survival and recovery. ``Destruction or 
    adverse modification of critical habitat'' is defined as an appreciable 
    reduction in the value of critical habitat for the survival and 
    recovery of a species. Given the imperiled status of the Devils River 
    minnow, it is likely that a Federal action that would destroy or 
    adversely modify the species' critical habitat would also jeopardize 
    its continued existence. Thus, prohibitions associated with critical 
    habitat would be duplicative and superfluous, and would, therefore, 
    provide no benefit to the species.
        Finally, critical habitat designation can sometimes serve to 
    highlight areas that may be in need of special management 
    considerations or protection. The continued existence of the Devils 
    River minnow is dependent upon the efforts of the TPWD and local land 
    owners, and those parties are aware of the areas in need of special 
    management considerations or protection. For these reasons, the 
    designation of critical habitat for the Devils River minnow would 
    provide no benefit to the species beyond that conferred by listing 
    alone and is, therefore, not prudent.
    
    Available Conservation Measures
    
        Conservation measures provided to species listed as endangered or 
    threatened under the Act include recognition, recovery actions, 
    requirements for Federal protection, and prohibitions against certain 
    practices. Recognition through listing results in public awareness and 
    conservation
    
    [[Page 14891]]
    
    actions by Federal, State, and local agencies, private organizations, 
    and individuals. The Act provides for possible land acquisition and 
    cooperation with the States and requires that recovery actions be 
    carried out for all listed species.
        The State of Texas is currently working on a conservation agreement 
    for the Devils River minnow. Because the agreement has not yet been 
    finalized, the Service did not consider it in determining whether to 
    issue this listing proposal. Should this agreement be finalized within 
    a reasonable period of time, and should the Service decide that it 
    potentially removes the need to list the species, the Service will 
    extend or reopen the comment period for this proposal to accept 
    comments on the agreement and its ability to remove the need to list 
    the species.
        Section 7(a) of the Act, as amended, requires Federal agencies to 
    evaluate their actions with respect to any species that is proposed or 
    listed as endangered or threatened and with respect to its critical 
    habitat, if any is being designated. Regulations implementing these 
    interagency cooperation provisions of the Act are codified at 50 CFR 
    part 402. Section 7(a)(4) requires Federal agencies to confer with the 
    Service on any action that is likely to jeopardize the continued 
    existence of a proposed species or result in destruction or adverse 
    modification of proposed critical habitat. If a species is listed 
    subsequently, section 7(a)(2) requires Federal agencies to ensure that 
    activities they authorize, fund, or carry out are not likely to 
    jeopardize the continued existence of such a species or to destroy or 
    adversely modify its critical habitat, if any has been designated. If a 
    Federal action may affect a listed species or its critical habitat, the 
    responsible Federal agency must enter into consultation with the 
    Service.
        Federal agency actions that may require conference and/or 
    consultation as described in the preceding paragraph include Army Corps 
    of Engineers review and approval of activities such as the construction 
    of roads, bridges, and dredging projects subject to Section 404 of the 
    Clean Water Act (33 U.S.C. 1344 et seq.) and Section 10 of the Rivers 
    and Harbors Act of 1899 (33 U.S.C. 401 et seq.) and U.S. Environmental 
    Protection Agency authorization of discharges under the National 
    Pollutant Discharge Elimination System. Other Federal agencies whose 
    actions could require consultation include the Department of Defense, 
    Natural Resources Conservation Service, the Federal Highways 
    Administration, and the Department of Housing and Urban Development.
        The Act and its implementing regulations set forth a series of 
    general prohibitions and exceptions that apply to all endangered 
    wildlife. The prohibitions, codified at 50 CFR 17.21, in part, make it 
    illegal for any person subject to the jurisdiction of the U.S. to take 
    (includes harass, harm, pursue, hunt, shoot, wound, kill, trap, 
    capture, or collect; or to attempt any of these), import or export, 
    ship in interstate commerce in the course of commercial activity, or 
    sell or offer for sale in interstate or foreign commerce any listed 
    species. It also is illegal to possess, sell, deliver, carry, 
    transport, or ship any such wildlife that has been taken illegally. 
    Certain exceptions apply to agents of the Service and State 
    conservation agencies.
        Permits may be issued to carry out otherwise prohibited activities 
    involving endangered wildlife under certain circumstances. Regulations 
    governing permits are codified at 50 CFR 17.22 and 17.23. Such permits 
    are available for scientific purposes, to enhance the propagation or 
    survival of the species, and/or for incidental take in the course of 
    otherwise lawful activities. Information collections associated with 
    these permits are approved under the Paperwork Reduction Act, 44 U.S.C. 
    3501 et seq., and assigned Office of Management and Budget clearance 
    number 1018-0094. For additional information concerning these permits 
    and associated requirements, see 50 CFR 17.22.
        It is the policy of the Service (59 FR 34272) to identify to the 
    maximum extent practicable at the time a species is listed those 
    activities that would or would not constitute a violation of section 9 
    of the Act. The intent of this policy is to increase public awareness 
    of the effect of the listing on proposed and on-going activities within 
    a species' range. The Service believes that, based on the best 
    available information, the following actions will not result in a 
    violation of section 9:
        (1) Normal livestock grazing and other standard ranching practices 
    which do not destroy or significantly degrade Devils River minnow 
    habitat.
        (2) Federally-approved projects that involve activities conducted 
    in accordance with any reasonable and prudent measures given by the 
    Service in accordance with section 7 of the Act.
        Activities the Service believes could potentially harm the Devils 
    River minnow and result in ``take'' include, but are not limited to:
        (1) Unauthorized collecting or handling of the species.
        (2) Any activities that may result in destruction or significant 
    alteration of habitat occupied by Devils River minnow including, but 
    not limited to, the discharge of fill material, the diversion or 
    alteration of spring and stream flows or withdrawal of groundwater to 
    the point at which habitat becomes unsuitable for the species, and the 
    alteration of the physical channels within the spring runs and stream 
    segments occupied by the species;
        (3) Discharge or dumping of pollutants such as chemicals, silt, 
    household or industrial waste, or other material into the springs or 
    streams occupied by Devils River minnow or into areas that provide 
    access to the aquifer and where such discharge or dumping could affect 
    water quality in spring outflows;
        (4) Herbicide, pesticide, or fertilizer application in violation of 
    label restrictions in or near the springs containing the species; and
        (5) Introduction of certain non-native species (fish, plants, and 
    other) into occupied habitat of the Devils River minnow or areas 
    connected to these habitats.
        In the descriptions of activities above, a violation of section 9 
    would occur if those activities occur to an extent that would result in 
    ``take'' of Devils River minnow. Not all of the activities mentioned 
    above will result in violation of section 9 of the Act; only those 
    activities which result in ``take'' of Devils River minnow would be 
    considered violations of section 9. Questions regarding whether 
    specific activities would constitute a violation of section 9 should be 
    directed to the Field Supervisor, Austin Ecological Services Field 
    Office (see ADDRESSES section).
        Requests for copies of the regulations regarding listed wildlife 
    and inquiries about prohibitions and permits may be addressed to U.S. 
    Fish and Wildlife Service, Region 2, Endangered Species Listing 
    Coordinator, 500 Gold Avenue SW., Room 4012, Albuquerque, New Mexico 
    87103-1306 (telephone 505/248-6655; facsimile 505/248-6922).
    
    Public Comments Solicited
    
        The Service intends that any final action resulting from this 
    proposal will be as accurate and as effective as possible. Therefore, 
    comments or suggestions from the public, other concerned governmental 
    agencies, the scientific community, industry, or any other interested 
    party concerning this rule are hereby solicited. Comments particularly 
    are sought concerning:
        (1) Biological, commercial trade, or other relevant data concerning 
    any
    
    [[Page 14892]]
    
    threat (or lack thereof) to the Devils River minnow;
        (2) The location of any additional populations of this species and 
    the reasons why any habitat should or should not be determined to be 
    critical habitat as provided by section 4 of the Act;
        (3) Additional information concerning the range, distribution, and 
    population size of the species;
        (4) Current or planned activities in the subject area and their 
    possible impacts on this species.
        Final promulgation of the regulation on this species will take into 
    consideration the comments and any additional information received by 
    the Service, and such communication may lead to a final regulation that 
    differs from this proposal.
        The Endangered Species Act provides for one or more public hearings 
    on this proposal, if requested. Requests must be received within 45 
    days of the date of publication of the proposal. Such requests must be 
    made in writing and addressed to the Field Supervisor, Austin 
    Ecological Services Field Office (see ADDRESSES section).
    
    National Environmental Policy Act
    
        The Fish and Wildlife Service has determined that an Environmental 
    Assessment, as defined under the authority of the National 
    Environmental Policy Act of 1969, need not be prepared in connection 
    with regulations adopted pursuant to section 4(a) of the Endangered 
    Species Act of 1973, as amended. A notice outlining the Service's 
    reasons for this determination was published in the Federal Register on 
    October 25, 1983 (48 FR 49244).
    
    Required Determinations
    
        This rule does not contain collections of information that require 
    approval by the Office of Management and Budget under 44 U.S.C. 3501 et 
    seq.
    
    References Cited
    
        A complete list of all references cited herein, as well as others, 
    is available upon request from the Austin Ecological Services Field 
    Office (see ADDRESSES section).
    
    Author
    
        The primary author of this proposed rule is Nathan Allan (see 
    ADDRESSES section).
    
    List of Subjects in 50 CFR Part 17
    
        Endangered and threatened species, Exports, Imports, Reporting and 
    recordkeeping requirements, Transportation.
    
    Proposed Regulation Promulgation
    
        Accordingly, the Service hereby proposes to amend part 17, 
    subchapter B of chapter I, title 50 of the Code of Federal Regulations, 
    as set forth below:
    
    PART 17--[AMENDED]
    
        1. The authority citation for part 17 continues to read as follows:
    
        Authority: 16 U.S.C. 1361-1407; 16 U.S.C. 1531-1544; 16 U.S.C. 
    4201-4245; Pub. L. 99-625, 100 Stat. 3500, unless otherwise noted.
    
        2. Amend section 17.11(h) by adding the following, in alphabetical 
    order under ``Fishes,'' to the List of Endangered and Threatened 
    Wildlife:
    
    
    Sec. 17.11  Endangered and threatened wildlife.
    
    * * * * *
        (h) * * *
    
    
    --------------------------------------------------------------------------------------------------------------------------------------------------------
                            Species                                                    Vertebrate                                                           
    --------------------------------------------------------                        population where                                  Critical     Special  
                                                                Historic range       endangered or         Status      When listed    habitat       rules   
               Common name                Scientific name                              threatened                                                           
    --------------------------------------------------------------------------------------------------------------------------------------------------------
                  Fishes                                                                                                                                    
                                                                                                                                                            
                       *                  *                  *                  *                  *                  *                  *                  
    Minnow, Devils River.............  Dionda diaboli......  U.S.A. (TX), Mexico  Entire.............  E               ...........           NA           NA
                                                                                                                                                            
                       *                  *                  *                  *                  *                  *                  *                  
    --------------------------------------------------------------------------------------------------------------------------------------------------------
    
        Dated: March 17, 1998.
    Jamie Rappaport Clark,
    Director, Fish and Wildlife Service.
    [FR Doc. 98-7997 Filed 3-26-98; 8:45 am]
    BILLING CODE 4310-55-P
    
    
    

Document Information

Published:
03/27/1998
Department:
Fish and Wildlife Service
Entry Type:
Proposed Rule
Action:
Proposed rule.
Document Number:
98-7997
Dates:
Comments from all interested parties must be received by July 27, 1998. Public hearing requests must be received by May 11, 1998.
Pages:
14885-14892 (8 pages)
RINs:
1018-AE86
PDF File:
98-7997.pdf
CFR: (1)
50 CFR 17.11