Endangered and Threatened Wildlife and Plants; Establishment of a Nonessential Experimental Population of Rio Grande Silvery Minnow in the Big Bend Reach of the Rio Grande in Texas, 74357-74372 [E8-28904]

Agencies

• Fish and Wildlife Service
• DEPARTMENT OF THE INTERIOR

[Federal Register Volume 73, Number 236 (Monday, December 8, 2008)]
[Rules and Regulations]
[Pages 74357-74372]
From the Federal Register Online via the Government Printing Office [www.gpo.gov]
[FR Doc No: E8-28904]


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DEPARTMENT OF THE INTERIOR

Fish and Wildlife Service

50 CFR Part 17

[FWS-R2-ES-2008-0031; 92220-1113-0000-C3]
RIN 1018-AU68


Endangered and Threatened Wildlife and Plants; Establishment of a 
Nonessential Experimental Population of Rio Grande Silvery Minnow in 
the Big Bend Reach of the Rio Grande in Texas

AGENCY: Fish and Wildlife Service, Interior.

ACTION: Final rule.

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SUMMARY: We, the U.S. Fish and Wildlife Service (Service), in 
cooperation with the National Park Service and the United States 
Section of the International Boundary and Water Commission, will 
reestablish the Rio Grande silvery minnow (Hybognathus amarus), a 
federally-listed endangered fish, into its historical habitat in the 
Big Bend reach of the Rio Grande in Presidio, Brewster, and Terrell 
Counties, Texas.
    We are reestablishing the Rio Grande silvery minnow under section 
10(j) of the Endangered Species Act of 1973, as amended (Act), and are 
classifying it as a nonessential experimental population (NEP). On the 
Rio Grande, the geographic boundaries of the NEP extend from Little Box 
Canyon downstream of Fort Quitman, Hudspeth County, Texas, through Big 
Bend National Park and the Rio Grande Wild and Scenic River, to Amistad 
Dam (Big Bend reach of the Rio Grande), Val Verde County, Texas. On the 
Pecos River, the geographic boundaries of the NEP extend from the 
river's confluence with Independence Creek to its confluence with the 
Rio Grande.
    This action is part of the recovery actions that the Service, 
Federal and State agencies, and other partners are conducting 
throughout the historic range of the species. This final rule

[[Page 74358]]

establishes the NEP and provides for limited allowable legal taking of 
Rio Grande silvery minnows within the defined NEP area. An 
Environmental Assessment (EA) and Finding of No Significant Impact have 
been prepared for this action (see ADDRESSES section below).

DATES: The effective date of this rule is December 8, 2008.

ADDRESSES: This final rule and environmental assessment are available 
on the Internet at https://www.regulations.gov and https://www.fws.gov/
southwest/es/AustinTexas/. Supporting documentation we used in 
preparing this final rule will be available for public inspection, by 
appointment, during normal business hours, at the Fish and Wildlife 
Service's office at 500 West Avenue H, Suite 104F, Alpine, Texas 79830.

FOR FURTHER INFORMATION CONTACT: Adam Zerrenner, Field Supervisor, 
Austin Ecological Services Field Office, 107011 Burnet Road, Suite 200, 
Austin, Texas 78758 (telephone 512-490-0057, facsimile 512-490-0974). 
If you use a telecommunications device for the deaf (TDD), call the 
Federal Information Relay Service (FIRS) at 800-877-8339.

SUPPLEMENTARY INFORMATION:

Background

    It is our intent to discuss only those topics directly relevant to 
the establishment of a Rio Grande silvery minnow NEP in this final 
rule. For more information on the Rio Grande silvery minnow, refer to 
the September 5, 2007, proposed rule (72 FR 50918) and the Rio Grande 
Silvery Minnow Draft Revised Recovery Plan (Service 2007a) (Draft 
Revised Recovery Plan).

Legislative

    The Act provides that species listed as endangered or threatened 
are afforded protection primarily through the prohibitions of section 9 
and the requirements of section 7. Section 9 of the Act, among other 
things, prohibits the take of endangered wildlife. ``Take'' is defined 
by the Act as harass, harm, pursue, hunt, shoot, wound, kill, trap, 
capture, or collect, or attempt to engage in any such conduct. Service 
regulations (50 CFR 17.31) generally extend the prohibitions of take to 
threatened wildlife. Section 7 of the Act outlines the procedures for 
Federal interagency cooperation to conserve federally listed species 
and protect designated critical habitat. It mandates that all Federal 
agencies use their existing authorities to further the purposes of the 
Act by carrying out programs for the conservation of listed species. It 
also states that Federal agencies will, in consultation with the 
Service, ensure that any action they authorize, fund, or carry out is 
not likely to jeopardize the continued existence of a listed species or 
result in the destruction or adverse modification of designated 
critical habitat. Section 7 of the Act does not affect activities 
undertaken on private land unless they are authorized, funded, or 
carried out by a Federal agency.
    Under section 10(j) of the Act, the Secretary of the Department of 
the Interior can designate reintroduced populations established outside 
the species' current range, but within its historical range, as 
``experimental.'' With the experimental population designation, the 
relevant population is treated as threatened for purposes of section 9 
of the Act, regardless of the species' designation elsewhere in its 
range. Threatened designation allows us greater discretion in devising 
management programs and special regulations for such a population. 
Section 4(d) of the Act allows us to adopt whatever regulations are 
necessary and advisable to provide for the conservation of a threatened 
species. In these situations, the general regulations that extend most 
section 9 prohibitions to threatened species do not apply to that 
species, and the 10(j) rule contains the prohibitions and exemptions 
necessary and appropriate to conserve that species.
    Based on the best scientific and commercial data available, we must 
determine whether the experimental population is essential or 
nonessential to the continued existence of the species. The regulations 
(50 CFR 17.80(b)) state that an experimental population is considered 
essential if its loss would be likely to appreciably reduce the 
likelihood of survival of that species in the wild. All other 
populations are considered nonessential.
    For the purposes of section 7 of the Act, we treat an NEP as a 
threatened species when the NEP is located within a National Wildlife 
Refuge or National Park, and section 7(a)(1) and the consultation 
requirements of section 7(a)(2) of the Act apply. Section 7(a)(1) 
requires all Federal agencies to use their authorities to carry out 
programs for the conservation of listed species. Section 7(a)(2) 
requires that Federal agencies, in consultation with the Service, 
insure that any action authorized, funded, or carried out is not likely 
to jeopardize the continued existence of a listed species or adversely 
modify its critical habitat. When NEPs are located outside a National 
Wildlife Refuge or National Park, we treat the population as proposed 
for listing, and only two provisions of section 7 apply--section 
7(a)(1) and section 7(a)(4). In these instances, NEPs provide 
additional flexibility because Federal agencies are not required to 
consult with us under section 7(a)(2). Section 7(a)(4) requires Federal 
agencies to confer (rather than consult) with the Service on actions 
that are likely to jeopardize the continued existence of a species 
proposed to be listed. The results of a conference are in the form of 
conservation recommendations that are optional as the agencies carry 
out, fund, or authorizeactivities. Activities that are not carried out, 
funded, or authorized by Federal agencies and are not on Federal lands 
are not affected by an NEP designation.
    Rio Grande silvery minnows that are used to establish an 
experimental population may come from a donor population, provided 
their removal will not create adverse impacts upon the parent 
population, and provided appropriate permits are issued in accordance 
with our regulations (50 CFR 17.22) prior to their removal. In the case 
of the Rio Grande silvery minnow, the donor population is a captive-
bred population that was propagated with the intention of re-
establishing wild populations to achieve recovery goals. In addition, 
it is possible that stock raised from wild eggs could also be released 
into the NEP area. Rio Grande silvery minnow eggs are collected from 
the wild population in New Mexico each year and are raised in captivity 
to provide individuals for captive propagation and augmentation of the 
wild population.
    Critical habitat has been designated for the Rio Grande silvery 
minnow in New Mexico (68 FR 8088-8135; February 19, 2003), and the 
designated critical habitat does not include this NEP area. Section 
10(j)(2)(C)(ii) of the Act states that critical habitat shall not be 
designated for any experimental population that is determined to be 
nonessential. Accordingly, we cannot designate critical habitat in 
areas where we have already established an NEP.

Biological Information

    The Rio Grande silvery minnow is one of seven species in the genus 
Hybognathus found in the United States (Pflieger 1980, p. 177). The 
species was first described by Girard (1856 in Service 1999, p. 38) 
from specimens taken from the Rio Grande near Fort Brown, Cameron 
County, Texas. It is a stout silvery minnow with moderately small eyes 
and a small, slightly oblique mouth. Adults may reach 5 inches (in)

[[Page 74359]]

(125 millimeters (mm)) in total length (Remshardt 2006). Its dorsal fin 
is distinctly pointed with the front of it located slightly closer to 
the tip of the snout than to the base of the tail. The fish is silver 
with emerald reflections. Its belly is silvery white; its fins are 
plain; and it does not have barbels (Sublette et al. 1990, pp. 129-
130).
    This species was historically one of the most abundant and 
widespread fishes in the Rio Grande Basin, occurring from 
Espa[ntilde]ola, New Mexico, to the Gulf of Mexico (Bestgen and 
Platania 1991, p. 225). It was also found in, but is now absent from, 
the Pecos River, a major tributary of the Rio Grande, from Santa Rosa, 
New Mexico, downstream to its confluence with the Rio Grande (Pflieger 
1980, p. 177). The Rio Grande silvery minnow is extirpated from the 
Pecos River and also from the Rio Grande downstream of Elephant Butte 
Reservoir and upstream of Cochiti Reservoir (Bestgen and Platania 1991, 
pp. 226-229). The current distribution of the Rio Grande silvery minnow 
is limited to the Rio Grande between Cochiti Dam and Elephant Butte 
Reservoir in New Mexico, which is only about 5 percent of its 
historical range (Bestgen and Platania 1991, pp. 226-229). Throughout 
much of its historical range, the decline of the Rio Grande silvery 
minnow has been attributed to modification of the flow regime 
(hydrological pattern of flows that vary seasonally in magnitude and 
duration, depending on annual precipitation patterns such as runoff 
from snowmelt), channel drying, reservoirs and dams, stream 
channelization, decreasing water quality, and perhaps interactions with 
nonnative fish (Cook et al. 1992, p. 42; Bestgen and Platania 1991, pp. 
229-230; Service 1999, pp. 1-2). Decreased river water quality caused 
by municipal and agricultural runoff (i.e., sewage and pesticides) as a 
result of the development of irrigated agriculture and the growth of 
cities within the historical range of the Rio Grande silvery minnow is 
also likely to have adversely affected the range and distribution of 
the Rio Grande silvery minnow (Service 1999, p. 2).
    The various life history stages of the Rio Grande silvery minnow 
require low-velocity habitats with a sandy and silty substrate that is 
generally associated with a meandering river that includes side 
channels, oxbows, and backwaters (Bestgen and Platania 1991, pp. 227-
228). It is not uncommon for Rio Grande silvery minnows in captivity to 
live beyond 2 years (Service 2007a, p. 8). However, although the Rio 
Grande silvery minnow is a hardy fish, capable of withstanding many of 
the natural stresses of the desert aquatic environment, its maximum 
documented longevity in the wild is about 25 months, and very few 
survive more than 13 months. Thus, a successful annual spawn 
(reproductive event) is key to the survival of the species (Service 
1999, p. 20; Dudley and Platania 2001, pp. 16-21; Dudley and Platania 
2002, p. 3). More information about the life history of, decline of, 
and threats to the Rio Grande silvery minnow can be found in the final 
designation of critical habitat for the species (February 19, 2003; 68 
FR 8088-8090), in the Rio Grande Silvery Minnow Recovery Plan (Recovery 
Plan; Service 1999, pp. 1-38), and the Draft Revised Recovery Plan 
(Service 2007a).
    The Rio Grande silvery minnow is extirpated from the Big Bend reach 
of the Rio Grande (Service 2007a, p. 10). The last documentation of a 
Rio Grande silvery minnow in the Big Bend reach of the Rio Grande was 
in 1960 (Bestgen and Platania 1991, p. 229). Natural repopulation is 
not possible without human assistance due to extensive reaches of river 
lacking Rio Grande silvery minnow habitat (including large reservoirs, 
where this species cannot survive) between where the species currently 
exists in the wild in New Mexico and the Big Bend reach.
    The Service contracted a study examining the suitability of the 
habitat in the Big Bend reach of the Rio Grande for the Rio Grande 
silvery minnow (Edwards 2005). The completed study indicates that there 
is a reasonable likelihood that Rio Grande silvery minnows will survive 
in this portion of the Rio Grande and become established. It also 
identifies the need for habitat restoration projects, with an emphasis 
on the removal of nonnative species, such as salt cedar (Tamarix 
chinensis) and giant river cane (also known as giant reed; Arundo 
donax), which can adversely affect aquatic habitat, including Rio 
Grande silvery minnow habitat (Edwards 2005, pp. 43-44). Reasons for 
the species' extirpation in the Rio Grande in Texas are uncertain, but 
are believed to have been due to a combination of low flows, caused by 
drought and water diversion from the river, and water pollution in the 
1950s (Edwards 2005, p. 3). However, the Big Bend reach has not 
experienced extensive drying since the drought of the 1950s and the 
extirpation of the Rio Grande silvery minnow. The continuing presence 
of members of the pelagic spawning guild (group of fish who broadcast 
semi-buoyant eggs into the water during reproduction) with life history 
requirements similar to the Rio Grande silvery minnow is evidence that 
the Big Bend reach of the Rio Grande may support reestablishment of Rio 
Grande silvery minnows (Edwards 2005, pp. 37-38). In addition, water 
quality in the Big Bend reach, which may have been one of the factors 
in the decline of the species, appears to be generally improving over 
time (Edwards 2005, p. 26).
    Throughout most of the NEP area, the lands along the Rio Grande are 
protected and managed on both the United States and Mexico side of the 
border by Federal, State, and private conservation-oriented landowners. 
These entities are all working together to conserve the aquatic and 
riparian habitats along 281 miles (452 kilometers) of the Rio Grande/
Rio Bravo. This provides a unique and significant measure of protection 
for the Rio Grande silvery minnow in the NEP area. We anticipate 
working with land managers and other interested parties, on a voluntary 
basis, to develop plans to further guide and accomplish habitat 
management and restoration activities, including removal and control of 
nonnative species, such as salt cedar and giant river cane.

Recovery Efforts

    We published the final rule to list the Rio Grande silvery minnow 
as an endangered species on July 20, 1994 (59 FR 36988). Restoring an 
endangered or threatened species to the point where it is recovered is 
a primary goal of our endangered species program. Thus, on July 1, 
1994, the Rio Grande Silvery Minnow Recovery Team (Recovery Team) was 
established under section 4(f)(2) of the Act and our cooperative policy 
on recovery plan participation, a policy intended to involve 
stakeholders in recovery planning (July 1, 1994; 59 FR 34272). Numerous 
individuals, agencies, and affected parties were involved in the 
development of the Recovery Plan or otherwise provided assistance and 
review (Service 1999, pp. 63-67). On July 8, 1999, we finalized the 
Recovery Plan (Service 1999, 71 pp.). The Recovery Plan has been 
updated and revised, and the Draft Revised Recovery Plan (Service 
2007a) was released for public comment on January 18, 2007 (72 FR 
2301). The Draft Revised Recovery Plan is currently in the process of 
being finalized, and thus, the final published version could be 
slightly different. In implementing and evaluating the success of this 
reintroduction effort, we will rely on the information in the Draft 
Revised Recovery Plan until the final revised Rio Grande Silvery Minnow 
Recovery Plan is published.
    The Draft Revised Recovery Plan describes recovery goals for the 
Rio

[[Page 74360]]

Grande silvery minnow (Service 2007a, pp. 66-73) and actions for their 
completion (Service 2007a, pp. 74-109). The three goals identified for 
the recovery and delisting of the Rio Grande silvery minnow are:
    (1) Prevent the extinction of the Rio Grande silvery minnow in the 
middle Rio Grande of New Mexico;
    (2) Recover the Rio Grande silvery minnow to an extent sufficient 
to change its status on the List of Endangered and Threatened Wildlife 
from endangered to threatened (downlisting). This may be considered 
when three populations (including at least two that are self-
sustaining) of the species have been established within the historical 
range of the species and have been maintained for at least 5 years; and
    (3) Recover the Rio Grande silvery minnow to an extent sufficient 
to remove it from the List of Endangered and Threatened Wildlife 
(delisting). This may be considered when three self-sustaining 
populations have been established within the historical range of the 
species, and they have been maintained for at least 10 years (Service 
2007a, p. 66).
    The Rio Grande silvery minnow's range has been so greatly 
restricted that the species is extremely vulnerable to catastrophic 
events, such as a prolonged period of low or no flow in its habitat in 
the middle Rio Grande in New Mexico (i.e., the loss of all surface 
water) (Dudley and Platania 2001, p. 21). Reestablishment of the Rio 
Grande silvery minnow in other areas of its historical range will 
assist in the species' recovery and long-term survival in part because 
it is unlikely that any single event would simultaneously eliminate the 
Rio Grande silvery minnow from three geographic areas (Service 1999, 
pp. 57-61).
    The Recovery Team developed a reach-by-reach analysis of the Rio 
Grande and Pecos River basins to identify the salient hydrological, 
chemical, and biological features of each reach. This analysis 
addressed the threats to the Rio Grande silvery minnow and considered 
the suitability of each reach for potential reestablishment (Service 
2007a, pp. 159-171). The Recovery Team's reach-by-reach analysis 
considered: (1) the reasons for the species' extirpation from the 
selected reach; (2) the presence of other members of the reproductive 
guild (pelagic spawner; non-adhesive, semibuoyant eggs); (3) habitat 
conditions (including susceptibility to river drying and presence of 
diversion structures); and (4) the presence of congeners (i.e., other 
fishes in the genus Hybognathus). After completing their analysis, the 
Recovery Team identified the Big Bend reach of the Rio Grande as the 
first priority for reestablishment efforts (Service 2007a, p. 160) (see 
``Reestablishment Area'' below for more details).
    In accordance with the Recovery Plan (Service 1999, pp. 60-61), we 
initiated a captive propagation program as a strategy to assist in the 
recovery of the Rio Grande silvery minnow in 2000. We currently have 
Rio Grande silvery minnows housed at: (1) the Service's Dexter National 
Fish Hatchery and Technology Center, Dexter, New Mexico; (2) the City 
of Albuquerque's Biological Park, Albuquerque, New Mexico; and (3) New 
Mexico State University, Las Cruces, New Mexico. These facilities are 
actively propagating and rearing Rio Grande silvery minnows. Offspring 
of these fish are currently being used to augment the Rio Grande 
silvery minnow population in the middle Rio Grande, New Mexico.
    Ongoing recovery efforts involving the release of captive-bred Rio 
Grande silvery minnows for augmentation of the population in the middle 
Rio Grande of New Mexico have demonstrated the potential viability of 
reestablishment as a tool for Rio Grande silvery minnow conservation. 
Captive propagation is conducted in a manner that will, to the maximum 
extent possible, preserve the genetic and ecological distinctiveness of 
the Rio Grande silvery minnow and minimize risks to existing wild 
populations consistent with our 2000 policy for captive propagation (65 
FR 56916) (Service 2007b, 26 pp.)
    Since 2000, approximately one million silvery minnows have been 
propagated (using both adult wild silvery minnows and wild-caught eggs) 
and then released into the wild in the middle Rio Grande in New Mexico 
(Remshardt 2008, p. 23). Wild gravid adults are successfully spawned in 
captivity at the City of Albuquerque's propagation facilities. Eggs 
left in the wild in the Rio Grande in New Mexico have a very low 
survivorship because many of them end up in Elephant Butte Reservoir 
where there is no suitable habitat for the species and the eggs are 
subject to a high rate of depredation. Spawning in captivity ensures 
that an adequate number of spawning adults are present to repopulate 
the river each year. While hatcheries continue to successfully spawn 
silvery minnows, wild eggs are collected to ensure genetic diversity 
within the remaining population. This program is carefully monitored so 
that it will not have an adverse effect on the wild population of Rio 
Grande silvery minnows in New Mexico.
    Direct and indirect evidence from the Rio Grande silvery minnow 
monitoring program indicates that augmentation efforts in the Rio 
Grande near Albuquerque, New Mexico, are contributing to an increase in 
catch rates (i.e., during seining) of marked and unmarked Rio Grande 
silvery minnows. The success of this augmentation effort indicates that 
hatchery-raised individuals can be released back to the wild with 
adequate retention in or near original release sites, experiencing 
survival of at least 2 years after release, and ultimately can 
contribute to future spawning efforts (Remshardt 2008, pp. 11-12).
    The source of Rio Grande silvery minnows for releases in the Big 
Bend reach will likely be from the Service's Dexter National Fish 
Hatchery and Technology Center, or another Service facility set up to 
provide fish specifically for this purpose. Expanding the Rio Grande 
silvery minnow's propagation program for potential releases into the 
Big Bend reach will result in more fish being produced overall and will 
not negatively impact the current program, which is producing Rio 
Grande silvery minnows for augmentation of the population in New Mexico 
(Service 2007b, pp. 6-7, 17-18).

Reestablishment Area

    The primary factors resulting in the determination by the Recovery 
Team that the Rio Grande reach from Presidio to Amistad Reservoir is 
the most suitable area for reintroduction efforts are: water quality 
and quantity; the presence of suitable habitat; an absence of barriers 
to fish movement within the reach; a lack of ongoing activities that 
are likely to adversely affect the Rio Grande silvery minnow; and the 
presence of designated conservation areas on both sides of the river 
that are managed for habitat protection and improvement by the State of 
Texas, the National Park Service, and governmental agencies and private 
organizations in Mexico (Edwards 2005, p. 11).
    River flow in the Big Bend reach is generally perennial, with a 
base flow of approximately 400 cubic feet per second (11.3 cubic meters 
per second). Severe flow reductions occurred only during the severest 
droughts in the 1950s. A period of intermittent drying did occur in 
2003. However, this drying event appears to have been brief and 
occurred in a small area. In addition, this reach of the river does not 
have flood control levies. It also contains only a few small, rock dam 
weirs, all but one of which

[[Page 74361]]

does not appear to be a barrier to fish movement (Foster's weir may be 
a barrier, but it is at the downstream end of the river reach deemed as 
suitable). The substrate ranges from silt to cobble and boulder 
depending on local conditions. Almost half of this reach is in canyons, 
including Big Bend National Park. The reach known as the lower canyons, 
from approximately Reagan Canyon to Bullis Fold, within the Rio Grande 
Wild and Scenic River, has spring input resulting in improved water 
quality and quantity. Outside the canyon reaches, the river is braided 
in some sections with a moderate gradient, providing areas of suitable 
habitat for Rio Grande silvery minnows. In addition, there are no 
regular channel maintenance activities in this reach.
    Based on the above information, we believe that the Rio Grande, 
from Mulato Dam (near the western border of Big Bend Ranch State Park) 
to Foster's Weir, east of the Terrell/Val Verde county line (the 
expected extent of reestablishment), contains suitable habitat for the 
Rio Grande silvery minnow and that it is likely the species can be 
successfully reestablished in the Big Bend reach. Establishing a viable 
population of Rio Grande silvery minnows in the Big Bend reach of the 
Rio Grande under this NEP designation would help achieve one of the 
primary recovery goals for downlisting and eventually delisting this 
species (see ``Recovery Efforts'' section above for more information). 
It is expected to take multiple introductions and several years of 
monitoring to evaluate if Rio Grande silvery minnows have become 
established and can be self-sustaining in this river reach.
    Therefore, we intend to release the Rio Grande silvery minnow into 
its historical habitat in this area. The NEP area, which encompasses 
all potential release sites, is located (1) in the Rio Grande, from 
Little Box Canyon downstream of Fort Quitman, Hudspeth County, Texas, 
through Big Bend National Park and the Rio Grande Wild and Scenic 
River, to Amistad Dam; and (2) in the Pecos River, from its confluence 
with Independence Creek to its confluence with the Rio Grande.
    Section 10(j) of the Act requires that an experimental population 
be geographically separate from other wild populations of the same 
species. This NEP area is isolated from existing populations of this 
species by large reservoirs. This fish is not known to survive in or 
move through large reservoirs due to the presence of unsuitable habitat 
and predators (64 FR 36275); therefore, the reservoirs will act as 
barriers to the species' downstream movement in the Rio Grande below 
Amistad Reservoir, and will ensure that this NEP remains geographically 
isolated and easily distinguishable from existing upstream wild 
populations in New Mexico. Based on the habitat requirements of the Rio 
Grande silvery minnow, we do not expect them to become established 
outside the NEP because they are unlikely to move into the unsuitable 
habitat at the edges of the NEP beyond the expected extent of 
reestablishment and are not able to move past physical barriers (dams 
and weirs) at either end of the NEP.
    The geographic extent of the NEP designation is larger than needed 
as only portions of the NEP area contain suitable habitat. However, as 
described above, this area represents what we believe to be the maximum 
geographic extent to which the fish could move if released in the Big 
Bend reach of the Rio Grande. We believe including this additional area 
provides a more effective recovery strategy by eliminating changing 
regulatory requirements in case Rio Grande silvery minnows unexpectedly 
move beyond the expected establishment area. If any of the released Rio 
Grande silvery minnows, or their offspring, move outside the designated 
NEP area, then the Service would consider these fish to have come from 
the NEP area, and we would propose to amend this 10(j) rule to enlarge 
the boundaries of the NEP area to include the entire range of the 
expanded populations.

Release Procedures

    Based on our experience with releasing the species to augment its 
population in New Mexico, we have determined that it would be best to 
release fish once per year in December or January. An implementation 
plan, including information about potential release sites, methods, and 
the number of individuals to be released, is appended to our 
environmental assessment (EA) and includes additional information on 
release sites, release timing, monitoring, and suggested management and 
research.
    As part of the Rio Grande silvery minnow augmentation program in 
New Mexico, we evaluated different release strategies such as time of 
year, time of day, specific release habitats, and various hatchery 
environments (natural outdoor ponds versus indoor facilities). All of 
this information adds to our knowledge of the species and will assist 
us in future recovery actions, such as providing release procedures and 
monitoring strategies for the reestablishment of Rio Grande silvery 
minnows in the Big Bend reach.

Status of Reestablished Population

    As described in the Recovery Plan and the Draft Revised Recovery 
Plan, reestablishment of populations within the Rio Grande silvery 
minnow's historical range is necessary to further the conservation and 
recovery of this species (Service 2007a, p. 67). The anticipated 
success of this reestablishment would enhance the conservation and 
recovery potential of this species by extending its present range into 
currently unoccupied historical habitat (Service 2007a, pp. 159-171). 
However, as required by section 10(j)(2)(B) of the Act, we have 
determined that this experimental population is not essential to the 
continued existence of the species in the wild for the following 
reasons:
    (1) We will ensure, through our section 10 permitting authority and 
the section 7 consultation process, that the use of Rio Grande silvery 
minnows from any donor population for releases in the Big Bend reach is 
not likely to jeopardize the continued existence of the species in the 
wild;
    (2) A population of Rio Grande silvery minnows exists in the middle 
Rio Grande, New Mexico, and the possible failure of the NEP that is the 
subject of this rule will not appreciably reduce the likelihood of 
survival of the species' existing wild population. Captive propagation 
facilities maintain a captive population, maximizing genetic diversity 
to the extent possible, and provide adequate numbers of Rio Grande 
silvery minnows to maintain the wild New Mexico population and also 
provide fish for releases in the Big Bend reach. The additional number 
of Rio Grande silvery minnows needed for reestablishment in the Big 
Bend reach will not inhibit the population augmentation efforts in the 
middle Rio Grande, New Mexico; and,
    (3) The captive population is protected against the threat of 
extinction from a single catastrophic event by housing Rio Grande 
silvery minnows in three separate facilities. Juvenile minnows produced 
in excess of the numbers needed to maintain the captive population and 
augment the wild population in New Mexico are available for 
reintroduction to the Big Bend reach. Some members of the experimental 
population are expected to die during the reintroduction efforts after 
removal from the captive population. The Service finds that even if the 
entire experimental population died, this would not appreciably reduce 
the prospects for future survival of the species in the wild. That is, 
the captive population could produce more surplus

[[Page 74362]]

minnows and future reintroductions still would be feasible if the 
reasons for the initial failure are understood. As a result, any loss 
of an experimental population in the wild will not threaten the 
survival of the species as a whole.
    In view of all these safeguards the Service finds that the 
reintroduced population would not be ``essential'' under 50 CFR 
17.81(c)(2). Essential status for experimental populations is not 
required by section 10(j) of the Act or the implementing regulations, 
and it has not been used in past reintroductions of captive-raised 
animals, such as the red wolf (Canis rufus), Mexican grey wolf (Canis 
lupus baileyi), blackfooted ferret (Mustela nigripes), and California 
condor (Gymnogyps californianus).

Location of Reintroduced Population

    Section 10(j) of the Act requires that an experimental population 
be geographically separate from other populations of the same species. 
On the Rio Grande, the geographic boundaries of the NEP extend from 
Little Box Canyon downstream of Fort Quitman, Hudspeth County, Texas, 
through Big Bend National Park and the Rio Grande Wild and Scenic 
River, to Amistad Dam (Big Bend reach of the Rio Grande). On the Pecos 
River, the geographic boundaries of the NEP extend from the river's 
confluence with Independence Creek to its confluence with the Rio 
Grande. The NEP area is isolated from the existing population of this 
species in New Mexico by hundreds of river miles, including large 
reservoirs and other areas of unsuitable habitat. The best available 
information indicates that large reservoirs serve as a barrier to 
movement for the Rio Grande silvery minnow because they contain many 
predators and do not contain suitable habitat for the species (64 FR 
36275). These reservoirs will ensure that this NEP remains 
geographically isolated and easily distinguishable from existing 
upstream wild populations in New Mexico. In addition, Amistad Reservoir 
will act as a barrier to the species' downstream movement in the Rio 
Grande.

Management

    The aquatic resources in the reestablishment area are managed by 
the National Park Service, the International Boundary and Water 
Commission, the State of Texas, and private landowners. Multiple-use 
management of these waters will not change as a result of the 
experimental population designation. Agricultural, recreational, and 
other activities by private landowners within and near the NEP area 
will not be affected by this rule and the subsequent release of the Rio 
Grande silvery minnow. Because of the exceptions provided by NEP 
designation, we do not believe the reestablishment of Rio Grande 
silvery minnows will conflict with existing human activities or hinder 
public use of the area.
    The Service, the National Park Service, the International Boundary 
and Water Commission, Texas Parks and Wildlife Department employees, 
and other conservation partners will plan and manage the 
reestablishment of Rio Grande silvery minnows. This group will closely 
coordinate on releases, monitoring, coordination with landowners and 
land managers, and public awareness, among other tasks necessary to 
ensure successful reestablishment of the species. The Service has also 
convened a Technical Team comprised of representatives from these 
agencies and other experts. This Technical Team assisted in the 
development of the Implementation and Monitoring Plan that is appended 
to the EA.
    (a) Mortality: The regulations implementing the Act define 
``incidental take`` as take that is incidental to, and not the purpose 
of, the carrying out of an otherwise lawful activity (50 CFR 17.3) such 
as recreation (e.g., fishing, boating, wading, trapping or swimming), 
forestry, agriculture, and other activities that are in accordance with 
Federal, Tribal, State, and local laws and regulations. Under this 
final 10(j) rule, take of Rio Grande silvery minnows within the 
experimental population area will be allowed provided that the take is 
unintentional and is not due to negligent conduct. The exception to 
this applies to Federal agencies, which must consult under section 7 of 
the Act on their activities that may affect the Rio Grande silvery 
minnow within Big Bend National Park or the Wild and Scenic River. We 
expect levels of incidental take to be low since the reestablishment is 
compatible with existing human use activities and practices for the 
area. More specific information regarding take can be found in the 
Final Regulation Promulgation section of this rule.
    (b) Special handling: In accordance with 50 CFR 17.21(c)(3), any 
employee or agent of the Service, any other Federal land management 
agency, or State personnel, designated for such purposes, may, in the 
course of their official duties and in association with the 
reestablishment program in the Big Bend reach, handle Rio Grande 
silvery minnows for scientific purposes; relocate Rio Grande silvery 
minnows to avoid conflict with human activities; relocate Rio Grande 
silvery minnows to other release sites for recovery purposes; aid sick 
or injured Rio Grande silvery minnows; and salvage dead Rio Grande 
silvery minnows. However, non-Service personnel and their agents will 
need to acquire permits from the Service for these activities.
    (c) Coordination with landowners and land managers: The Service and 
cooperators have identified issues and concerns associated with Rio 
Grande silvery minnow reestablishment through the National 
Environmental Policy Act (NEPA) (42 U.S.C. 4321 et seq.) scoping 
comment period. The reestablishment also has been discussed with 
potentially affected State agencies and private landowners. Affected 
State agencies, landowners, and land managers have indicated support 
for the reestablishment, provided an NEP is designated and land and 
water use activities in the NEP area are not constrained.
    (d) Monitoring: The Service has developed an implementation and 
monitoring plan specific to this NEP and associated reestablishment 
efforts. After the initial release of Rio Grande silvery minnows, we 
will monitor their presence or absence at least annually and document 
any spawning behavior or young-of-year fish that might be present. 
Section 6 funding has been approved for pre-release and quarterly 
monitoring associated with this project for the first 2 years. 
Depending on available resources, quarterly monitoring will likely 
continue, especially during the first few years of reestablishment 
efforts. This monitoring will be conducted primarily by seining and 
will be accomplished by Service, National Park Service, or State 
employees or by contracting with the appropriate species experts. 
Annual reports will be produced detailing stocking and monitoring 
activities that took place during the previous year. We will also fully 
evaluate these reestablishment efforts every 5 years to determine 
whether to continue or terminate them.
    (e) Disease: All Federal fish hatcheries rearing and producing fish 
are inspected annually as per the Service's Aquatic Animal Health 
Policy using the American Fisheries Society, Fish Health Section Blue 
Book Standards. Facilities must maintain a Class-A certification, 
meaning they are free of all tested pathogens, in order to stock fish 
into the wild. Targeted pathogens include internal and external 
parasites, bacteria, and viruses. Dexter National Fish Hatchery and 
Technology Center, where Rio Grande silvery minnows are currently being 
raised for augmentation

[[Page 74363]]

and reintroduction efforts, has qualified as a Class-A facility for 76 
years, since it was constructed. In addition to the standard yearly 
fish health inspection, an additional Fish Lot inspection will be 
completed on the Rio Grande silvery minnow destined for the Big Bend 
reach 30 days prior to being transported to release sites. This 
inspection will be conducted according to the guidelines listed above. 
If any of the targeted pathogens are diagnosed the fish will not be 
released and remedial actions will be taken immediately. Any additional 
facilities that are used to raise Rio Grande silvery minnows for this 
re-establishment effort will also be regularly inspected to ensure that 
they meet the standards described above.
    (f) Genetic variation: In cooperation with conservation partners 
with expertise in the captive propagation of Rio Grande silvery minnows 
and genetics management, the Service has formed a Rio Grande Silvery 
Minnow Captive Propagation and Genetics Workgroup. This group worked 
with Dexter National Fish Hatchery and Technology Center to develop the 
Rio Grande Silvery Minnow Genetics Management and Propagation Plan 
(Service 2007b, 26 pp.) and meets regularly to plan the captive 
propagation contribution to the recovery of the Rio Grande silvery 
minnow and provide fish for restoration and augmentation in the middle 
Rio Grande and reintroduction of the species into other areas of its 
historical range.
    The propagation strategy is based on two key elements: (1) the 
collection of eggs from the middle Rio Grande to meet the majority of 
targeted stocking numbers, and (2) maintaining fish from the annual 
wild egg collection as broodstock in the event catastrophic changes 
occur in the river. These actions minimize the risk to the extant 
population by preventing broodstock mining and maximize the potential 
to replicate as closely as possible a natural recruitment cycle. The 
propagation program will be contingent on an orchestrated balance 
between the use of wild-caught eggs and captive propagation that will 
require ongoing monitoring of river populations and genetic monitoring 
of wild and captive stocks (Service 2007b, p. 2).
    The propagation program will use a combination of wild-egg 
collections and hatchery spawning of fish from wild-eggs (F1) to 
produce fish for stocking. Eggs will be collected in the river every 
spring from natural spawning events and delivered to propagation 
facilities. The majority of these eggs drift into hostile waters such 
as Elephant Butte reservoir or river reaches that become dewatered. The 
eggs will be hatched, and larval fish reared to adulthood in captivity. 
A small portion from each year class will be retained as captive 
broodstock. If recruitment fails in any given year, the captive stock 
can be used to produce fish to maintain the species through the next 
year (Service 2007b, p. 2).
    Additionally, paired or communal spawning will be conducted 
annually. Ongoing genetic monitoring will be used to ensure a minimum 
number of breeding animals contribute to the next generation. We expect 
that in low water years, when natural spawning is not expected to yield 
adequate numbers of eggs for the program, captive propagation will be 
required in terms of increasing the genetic effective population size, 
and to meet targeted stocking numbers (Service 2007b, pp. 2-3).
    The Rio Grande Silvery Minnow Genetics Management and Propagation 
Plan is designed to provide a strategy for maintenance of genetic 
diversity in the species. In concert with strategies to address the 
underlying cause of the species' decline, fish from collected eggs and 
captively propagated fish will ensure long-term survival and recovery 
of the Rio Grande silvery minnow by providing offspring appropriate for 
reintroduction as identified in the Draft Revised Recovery Plan 
(Service 2007a) and in the Service's conservation strategy for the 
species (67 FR 39212).
    (g) Protection of Rio Grande silvery minnows: We will transport Rio 
Grande silvery minnows from hatcheries to release sites using methods 
developed from our experience with augmenting the species' population 
in New Mexico. We will release Rio Grande silvery minnows using a 
``soft'' release technique that provides short-term protection from 
natural predators and allows individuals to acclimate to their new 
environment. This soft release technique includes placing the minnows 
in holding pens in the river before releasing them to the wild. Rio 
Grande silvery minnows will be released into reaches of the Rio Grande 
within the NEP that we have determined to have the best habitat 
available. Should causes of mortality be identified, we will work with 
the private landowners or agency land managers to try to correct the 
problem. As reestablishment and monitoring efforts proceed, we will use 
the knowledge gained to further refine transport and release methods.
    (h) Public awareness and cooperation: On August 9, 2005, we mailed 
letters to potentially affected Congressional offices, Federal and 
State agencies, local governments, landowners, and interested parties 
to notify them that we were considering proposing NEP status in the Rio 
Grande and Pecos River for the Rio Grande silvery minnow. We received a 
total of 10 responses during the September 2005 scoping meetings and 
comment period. The comments received are listed in the EA and have 
been considered in the formulation of alternatives considered in the 
NEPA process. The following section describes the public outreach we 
conducted and the responses received during the public and peer review 
comment period on the proposed rule and draft EA.

Summary of Public and Peer-Review Comments and Recommendations

    We requested written comments from the public on the proposed NEP 
and draft EA in the proposed rule published on September 5, 2007 (72 FR 
50918). We also contacted the appropriate Federal, State, and local 
agencies; Tribes; scientific organizations; and other interested 
parties and invited them to comment on the proposed rule. The initial 
comment period was open from September 5, 2007, to November 5, 2007. In 
response to requests from interested parties, a second comment period 
was open from February 22, 2008, through March 10, 2008 (73 FR 9755).
    In accordance with our policy on peer review, published on July 1, 
1994 (59 FR 34270), we solicited opinions from three expert aquatic 
biologists who are familiar with this species regarding pertinent 
scientific or commercial data and assumptions relating to supportive 
biological and ecological information for the proposed rule. Reviewers 
were asked to review the proposed rule and the supporting data, to 
point out any mistakes in our data or analysis, and to identify any 
relevant data that we might have overlooked. All three of the peer 
reviewers submitted comments and were generally supportive of the 
proposal to reestablish Rio Grande silvery minnow in the Big Bend 
reach. Their comments are included in the summary below and/or 
incorporated directly into this final rule.
    We reviewed all comments received from the peer reviewers, State 
agencies, and the public for substantive issues and new information 
regarding the proposed NEP. Substantive comments received during the 
comment period have either been addressed below or incorporated 
directly into this final rule. The comments are grouped below as peer 
review, State, or public comments.
    We received comments from 14 parties, including comments from 
natural resource management agencies

[[Page 74364]]

in Mexico and from three peer reviewers. Nine of the 14 commenters 
specifically expressed support for reestablishing the silvery minnow in 
the Big Bend reach of the Rio Grande. None of the commenters 
specifically opposed the reintroduction of the Rio Grande silvery 
minnow to the Big Bend reach, except for one commenter, who stated that 
they would be opposed to reintrodcution if it would reduce or make less 
reliable El Paso's surface water supply. Seven of the 14 parties 
expressed an opinion on the proposal to designate the experimental 
population as nonessential; of these, five commenters expressed support 
for a NEP, while two commenters, including one peer reviewer, expressed 
concern that a NEP designation would not provide enough protection for 
the silvery minnow.
    Comments in support of the proposed action by peer reviewers 
included agreement with the following determinations: (1) the proposed 
NEP is wholly separate geographically from existing populations of Rio 
Grande silvery minnows; (2) establishment of a second population of Rio 
Grande silvery minnows is essential for the recovery of the species; 
(3) the Big Bend reach of the Rio Grande likely provides the best 
location for a second population; and (4) it seems appropriate to 
assume that Rio Grande silvery minnows will not become established 
outside of the proposed NEP area. One peer reviewer also agreed with 
our assertion that the continuing presence of speckled chub 
(Macrhybopsis aestivalis) indicates that the proposed action seems to 
have a reasonably high probability of success. Commenters from Mexico's 
National Institute of Ecology indicated that the reintroduction of Rio 
Grande silvery minnows is a very important initiative for species 
conservation and habitat restoration on this reach of the Rio Grande.

Peer-Review Comments

    (1) Comment: All three peer reviewers and one commenter asked 
whether an NEP is an acceptable component of recovery or if another 
rulemaking is necessary to reclassify the population before it can be 
counted toward recovery.
    Our Response: Section 10(j) and its implementing regulations 
require that experimental reintroduction activities further the 
conservation of the species. Because these actions are directly guided 
by the Recovery Plan (Service 1999) and the Draft Revised Recovery Plan 
(Service 2007a), if our efforts to reestablish the Rio Grande silvery 
minnow in the Big Bend reach result in a self-sustaining population (as 
described in the species' Draft Revised Recovery Plan or the final 
revised version, once it is published), then the NEP will be counted 
toward the recovery of the species. This would not require an 
additional rulemaking effort.
    Our intent is for the 10(j) rule to remain in place until the 
status of the species improves to a point where listing is no longer 
necessary, as defined by the Draft Revised Recovery Plan or the final 
revised version, and the Rio Grande silvery minnow can be delisted. 
Once the threats to the Rio Grande silvery minnow are reduced and at 
least three populations are self-sustaining, the Service will likely 
publish a proposed rule to delist the Rio Grande silvery minnow in the 
Federal Register. During the proposed delisting process, there would be 
opportunities for the public to comment and request public hearings. 
Information gathered during the public comment period would be 
incorporated into our evaluation of the species' listing status. If we 
were to determine that listing is no longer appropriate, a final rule 
delisting the Rio Grande silvery minnow would then be published in the 
Federal Register.
    (2) Comment: An augmentation plan with a genetics management 
strategy is necessary and should be identified as the first step by the 
Service.
    Our Response: The Implementation and Monitoring Plan, found in 
Appendix B of the EA, includes information about reintroduction 
implementation and genetic and population monitoring. In cooperation 
with conservation partners with expertise in the captive propagation of 
Rio Grande silvery minnows and genetics management, we have formed a 
Rio Grande Silvery Minnow Captive Propagation and Genetics Workgroup. 
This group worked with Dexter National Fish Hatchery and Technology 
Center to develop the Rio Grande Silvery Minnow Genetics Management and 
Propagation Plan. The group meets regularly to plan the captive 
propagation contribution to the recovery of the Rio Grande silvery 
minnow and provide fish for restoration and augmentation in the middle 
Rio Grande and reintroduction of the species into other areas of its 
historical range. Please refer to the Implementation and Monitoring 
Plan appended to the EA and the Rio Grande Silvery Minnow Genetics 
Management and Propagation Plan (Service 2007b) for more information.
    (3) Comment: One peer reviewer and several commenters indicated 
that the implementation and monitoring plan lacked detailed information 
and should be expanded.
    Our Response: We intend that the Implementation and Monitoring 
Plan, which is appended to the EA, be used as a guide for adaptive 
management and monitoring. We have added more specific information 
about release sites, techniques, and monitoring for the first year of 
the project and will be revisiting this document on a yearly basis, 
along with our partners in implementing the project, as part of an 
assessment of what we have learned and what might need to be adapted 
for best management. From our conservation efforts on this and other 
species, we know that it may take several years of effort before we can 
more clearly judge the likelihood of success of reintroduction. 
Information gathered as reintroduction proceeds will be used to 
evaluate the progress of the reintroduction program.
    (4) Comment: One peer reviewer expressed concern that an NEP of Rio 
Grande silvery minnows in the Big Bend reach could be used to reduce 
the pressure towards conservation of the species in New Mexico. Another 
peer reviewer and a commenter stated that with the increasing reliance 
on augmentation of the only wild population of Rio Grande silvery 
minnows in New Mexico, captive populations are increasingly important 
and in need of protection. They further commented that establishment of 
``nonessential'' populations should not be attempted if such efforts 
detract from recovery activities in the middle Rio Grande of New Mexico 
or adversely affect the species in that area. One commenter stated that 
there must be some assurance that use of captively propagated Rio 
Grande silvery minnows are not sacrificed for want of a detailed 
monitoring plan, reasoned assumptions, rigorous evaluations, and ample 
financial resources to implement the project.
    Our Response: The Service will continue to use our authorities 
under the Act to protect the wild population of Rio Grande silvery 
minnows in New Mexico. The Draft Revised Recovery Plan clearly defines 
criteria for downlisting and delisting the species, including 
stabilizing the population in New Mexico, as well as establishing self-
sustaining populations in other areas of the species' historical range. 
We will also ensure, through our section 10 permitting authority and 
the section 7 consultation process, that the use of Rio Grande silvery 
minnows from the captive population for releases in the Big Bend reach 
is not likely to jeopardize the continued existence of the species in 
the wild. Expanding the Rio Grande silvery minnow's propagation program 
for potential

[[Page 74365]]

releases into the Big Bend reach will result in more fish being 
produced overall and will not negatively affect the current program, 
which is producing Rio Grande silvery minnows for augmentation of the 
population in New Mexico.
    Additionally, we note that conservation efforts by us and our 
conservation partners are always subject to funding support by 
Congress, State legislatures, or private individuals and organizations. 
Although we have no guarantees about funding in future years, we have a 
reasonable expectation that we and/or our partners will be able to 
carry out the monitoring activities that we have identified as 
appropriate. Please also see our response to Comment 3.
    (5) Comment: The final rule should include an evaluation of threats 
to the species as they may exist in the area of the proposed NEP.
    Our Response: Throughout much of its historical range, the decline 
of the Rio Grande silvery minnow has been attributed to modification of 
the flow regime, channel drying, reservoirs and dams, stream 
channelization, decreasing water quality, and perhaps interactions with 
non-native fish. Development of agriculture and the growth of cities 
within the historical range of the Rio Grande silvery minnow resulted 
in a decrease in the quality of river water caused by municipal and 
agricultural runoff (i.e., sewage and pesticides) that may have also 
adversely affected the range and distribution of the Rio Grande silvery 
minnow. More information on threats to the Rio Grande silvery minnow 
within its current and historical range can be found in the final 
designation of critical habitat for the species (February 19, 2003; 68 
FR 8088-8090), in the Rio Grande Silvery Minnow Recovery Plan (Recovery 
Plan; Service 1999, pp. 1-38), and the Draft Revised Recovery Plan 
(Service 2007a).
    Please see the Biological Information section of this rule for a 
brief summary of potential threats to the species in the Big Bend 
reach. A more detailed summary and evaluation of potential threats to 
the species in the Big Bend reach can be found in the document, 
Feasibility of Reintroducing Rio Grande Silvery Minnows (Hybognathus 
amarus) to the Rio Grande, Big Bend Region, Texas (Edwards 2005). In 
general, the threats described above apply to the Big Bend reach and 
were evaluated prior to publication of the proposed rule. However as 
described in the feasibility study (Edwards 2005) and as compared to 
other areas of the species' historical range, as well as its current 
range in New Mexico, the expected establishment area in the Big Bend 
reach does not have any major dams or diversions that would block the 
upstream movement of fish, has not experienced prolonged and extensive 
channel drying since the 1950s, and has water quality that has 
generally improved since the species' extirpation from the NEP area. 
Water quality improvements can be attributed to decreasing agricultural 
run-off along the banks of the Rio Grande (as a result of less 
agriculture in the area in general) and improved treatment of municipal 
sewage (Edwards 2005).
    Until we release Rio Grande silvery minnows into the Big Bend reach 
and monitor the population, as well as that of other fish in the area, 
we do not know how Rio Grande silvery minnows will be affected by other 
native and non-native fish in this area. As the experimental 
reintroduction proceeds we will be gathering information to assist us 
in identifying and quantifying potential threats to the species in this 
area.
    (6) Comment: The rule should identify that the Draft Revised 
Recovery Plan identifies a density of >5 fish/100 m\2\ as necessary for 
downlisting and delisting the species and provide an evaluation, based 
on habitat relationships, of the likelihood that this density can be 
achieved in the NEP area.
    Our Response: A Catch per Unit Effort (CPUE) of >5 fish/100 m\2\ is 
identified in the Draft Revised Recovery Plan as a component of the 
down-listing and delisting goals for the species in the middle Rio 
Grande of New Mexico. The Service is currently working with the 
Conservation Breeding Specialist Group, which operates under the 
International Union for Conservation of Nature's Species Survival 
Commission; the Middle Rio Grande Endangered Species Collaborative 
Program; and other conservation cooperators to develop a population 
viability analysis for the middle Rio Grande and the Big Bend reach. 
This analysis will assist us in refining our conservation and recovery 
efforts for the species and in determining a realistic population goal 
for the species in the Big Bend reach.
    (7) Comment: The experimental population in the Big Bend reach 
should be designated as an ``essential'' population under the Act. 
Much, if not all, of the argument for ``nonessential experimental'' is 
not biologically or scientifically based and is thus discountable. 
Because of the vulnerability of the New Mexico population, additional 
populations of Rio Grande silvery minnows are essential to the 
continued existence of the species.
    Our Response: Although additional populations of Rio Grande silvery 
minnows are clearly essential to the recovery of the species, we have 
determined that the Big Bend population is not essential to the 
continued existence of the species in the wild and should therefore be 
designated as an NEP. Please see the ``Status of the Reestablished 
Population'' section of this final rule for more information.
    We believe that releasing Rio Grande silvery minnows under the 
section 10(j) NEP provision of the Act is the most appropriate way to 
achieve conservation for this species in the Big Bend reach and that 
this action is consistent with the purposes of the Act. In coordination 
with the Rio Grande Captive Propagation and Genetic Management Working 
Group and our permitting authorities under section 10 of the Act, we 
will ensure that our efforts to reestablish the species in the Big Bend 
reach do not adversely affect the wild population of Rio Grande silvery 
minnows in New Mexico.

State Comments

    (8) Comment: The New Mexico Interstate Stream Commission indicated 
that they understand the NEP will not adversely affect current 
beneficial uses of water and that they support the reestablishment of 
Rio Grande silvery minnows in the Big Bend reach as a means of 
ultimately recovering the species. They also noted that the Draft 
Revised Recovery Plan calls for reintroduction of the species into a 
total of three suitable parts of its historical range in addition to 
the current wild population in New Mexico. They suggested that the 
Service consider a programmatic approach for such reintroductions so 
that more than one reintroduction can be considered within the same 
NEPA and 10(j) rulemaking process.
    Our Response: We appreciate the support and suggestion of the New 
Mexico Interstate Stream Commission. However, we feel it is prudent to 
focus on one initial area for reintroduction at this time so that we 
can gain a better understanding of the process of reintroducing this 
species and apply the lessons we learn to potential future 
reintroduction efforts in other areas of the species' historical range. 
Additionally, the Big Bend reach of the Rio Grande has been widely 
recognized as having the highest potential for successful 
reintroduction of the Rio Grande silvery minnow within its historical 
range. Other potential reintroduction areas need to be examined more 
closely and potential obstacles to successful reintroduction

[[Page 74366]]

addressed prior to making attempts at reintroduction. Please see the 
Draft Revised Recovery Plan (Service 2007a) for more information.

Public Comments

    (9) Comment: El Paso Water Utilities (EPWU) stated that they are 
supportive of recovery efforts for the Rio Grande silvery minnow and 
would be very pleased for the species to recover to such an extent that 
it might no longer be endangered. However, comments from EPWU and also 
the Elephant Butte Irrigation District (EBID) indicated that they are 
mindful of the impact that the Rio Grande silvery minnow has had on 
water management in New Mexico and particularly on water delivered from 
U.S. Bureau of Reclamation projects. For this reason, they are opposed 
to any action that would reduce or make their surface water supply less 
reliable than it already is, including ``confiscating'' water from 
upstream users to enhance or maintain flows in the Rio Grande below El 
Paso.
    Our Response: We appreciate the support of EPWU for our efforts to 
recover the Rio Grande silvery minnow and understand its concerns about 
water management. In the proposed rule, this final rule, and the draft 
and final versions of the EA, we clearly state that we do not intend to 
have an adverse effect on water rights in implementing this project.
    Additionally, the NEP designation does not provide a mechanism for 
us to require upstream water users to provide water resources to the 
NEP area. If water was supplied to the NEP area from upstream water 
users to enhance or maintain flows it would be done as a voluntary 
conservation measure. In order to require that upstream users must 
deliver additional water resources downstream, we must determine that 
an action with a Federal nexus is causing jeopardy to the species and 
that the reasonable and prudent alternative to the proposed action was 
to let water down. Because this population has been determined to be 
nonessential to the existence of the species, we would not be able to 
make a determination of jeopardy to the species due to effects on the 
NEP. In other words, in order to determine if this population is 
``essential'' or ``nonessential'' under section 10(j)(2)(B) of the Act, 
we have already found that the loss of the fish in the NEP area would 
not jeopardize the continued existence of the species. Thus, any 
projects occurri