[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

[[Page 14888]]

(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