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

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

[[Page 14889]]

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