[Federal Register: April 2, 2004 (Volume 69, Number 64)]
[Proposed Rules]               
[Page 17383-17386]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]



Fish and Wildlife Service

50 CFR Part 17

RIN 1018-AT35

Endangered and Threatened Wildlife and Plants; Withdrawal of 
Proposed Rule To Reclassify the Pahrump Poolfish (Empetrichthys latos) 
From Endangered to Threatened Status

AGENCY: Fish and Wildlife Service, Interior.

ACTION: Proposed rule; withdrawal.


SUMMARY: We, the U.S. Fish and Wildlife Service (Service), withdraw the 
proposed rule, published in the Federal Register on September 22, 1993 
(58 FR 49279), to reclassify the Pahrump poolfish (Empetrichthys latos) 
from endangered to threatened status. We have determined that 
reclassification of this species at this time is not appropriate.

ADDRESSES: The complete file for this action is available for 
inspection, by appointment, during normal business hours at our 
Southern Nevada Field Office, 4701 North Torrey Pines Drive, Las Vegas, 
Nevada 89130.

FOR FURTHER INFORMATION CONTACT: Robert D. Williams, Nevada Fish and 
Wildlife Office, 1340 Financial Boulevard, Suite 234, Reno, Nevada 
89502 (telephone: 775/861-6300; facsimile: 775/861-6301).



    The Pahrump poolfish, family Goodeidae, was discovered by Gilbert 
in 1893, but was incorrectly identified as the Ash Meadows killifish 
(Empetrichthys merriami). Miller (1948) later described the Pahrump 
poolfish as the Pahrump killifish (Empetrichthys latos latos), which 
historically occupied an isolated spring (Manse Spring) on private 
property known as Manse Ranch in the Pahrump Valley of southern Nye 
County, Nevada.
    When describing the Pahump killifish, Miller also identified two 
other subspecies occurring in isolated springs in Nye County, the 
Pahrump Ranch killifish (Empetrichthys latos pahrump) inhabiting 
Pahrump Spring, and the Raycraft Ranch killifish (E. l. concavus) 
occurring in Raycraft Spring. Both of these subspecies became extinct 
in the late 1950s as a result of introduced carp (Cyprinus spp.) and 
desiccation of the springs from groundwater pumping (Miller 1948; 
Deacon and Williams 1984; Miller et al. 1989).
    The only congener (member of the same genus) to these three 
subspecies, the Ash Meadows killifish, was documented by Gilbert (1893) 
and historically occupied numerous springs in nearby Ash Meadows, Nye 
County, Nevada. This species was last seen in 1948 and is believed to 
have gone extinct in the early 1950s, likely as a result of habitat 
alteration, and competition with and predation by, introduced nonnative 
crayfish (Procambarus clarkii), mosquitofish (Gambusia affinis), black 
mollies (Mollienesia shenops), and bullfrogs (Rana catesbiana) (Deacon 
and Nappe 1968; Soltz and Naiman 1978; Miller et al. 1989).
    The common name of the genus Empetrichthys has since been changed 
from killifish to poolfish (Robins et al. 1991). Also, because the 
Pahrump poolfish (Empetrichthys latos latos) is now the only remaining 
representative of the species E. latos, the subspecies designation has 
been dropped; thus, the fish is currently known as the Pahrump poolfish 
(E. latos) (Robins et al. 1991; Eschmeyer 1998; Integrated Taxonomic 
Information System 2002).
    The Pahrump poolfish (poolfish) is a small fish that obtains an 
average maximum length of 3 inches (76.2 millimeters), with females 
generally larger than males (Service 1980; Deacon 1984a, 1984b, 1984c). 
The poolfish has a slender, elongate body with dorsal and anal fins 
placed far back, a broad upturned mouth, a dark longitudinal streak 
(which tends to disappear in older, larger individuals), and an orange 
ring around the eyes. On average, there are 30 to 32 scales in the 
lateral series (scales found along the lateral line, which is a series 
of porelike openings along the sides of a fish), but the number may 
vary from as low as 29 to a high of 33 scales (Sigler and Sigler 1987; 
La Rivers 1994). Poolfish lack pelvic fins, but the dorsal, anal, and 
caudal fins are bright orange-yellow when the fish are in an 
environment of optimal temperature and dissolved oxygen (Selby 1977; 
Soltz and Naiman 1978). The pectoral fins of the species typically have 
16 to 18 rays (Sigler and Sigler 1987). The body of the poolfish is 
generally greenish-brown with black mottling, but males may be silver-
blue without mottling during the spawning season (Soltz and Naiman 
1978; Service 1980).
    Transplant History: In 1975, poolfish were extirpated from their 
only known natural habitat, Manse Spring, as a result of desiccation of 
the spring from groundwater pumping and competition from nonnative 
goldfish (Deacon et al. 1964; J. Deacon, in litt. 1970). Anticipating 
the demise of the spring at Manse Ranch (Minckley and Deacon 1968), 
personnel from Federal and State agencies and academic institutions 
removed poolfish from Manse Spring during the early 1970s and 
transplanted poolfish to three locations in Nevada:
    1. Los Latos Pool along the Colorado River, near Lake Mohave in 
June 1970 (J. Deacon in litt. 1970);
    2. Corn Creek Springs on the Desert National Wildlife Refuge 
(DNWR), Clark

[[Page 17384]]

County in August 1971 (D. Lockard, Service, in litt. 1971); and
    3. Shoshone Ponds Natural Area, White Pine County, a Bureau of Land 
Management (BLM) native fish sanctuary in March 1972 (D. Lockard in 
litt. 1972; Mark Barber, BLM, in litt. 1987).
    Transplanted poolfish at Los Latos Pool were lost during floods in 
the late 1970s, and individuals were never replaced at this location. 
Poolfish at Shoshone Ponds Natural Area were lost to vandalism in 1974 
when the water source was intentionally turned off. Modifications were 
made to the ponds' water system to try to prevent future vandalism, and 
the poolfish were replaced in August 1976 with fish from Corn Creek 
Springs (after a 1-year stay at a University of Nevada, Las Vegas 
holding facility) (Leroy McLelland, Nevada Division of Fish and Game 
(NDFG), in litt. 1976; Logan 1977; M. Barber in litt. 1987). In order 
to replace the lost Los Latos Pool population, a third population of 
poolfish was established in the irrigation reservoir at the State of 
Nevada's Spring Mountain Ranch State Park (State Park) in western Clark 
County. Poolfish from Corn Creek Springs were transplanted to the State 
Park location in June 1983 (Richard Haskins, NDFG, in litt. 1983).
    We approved the Pahrump Killifish Recovery Plan (Recovery Plan) on 
March 17, 1980 (Service 1980). The Recovery Plan recommended the 
establishment of at least three populations of poolfish as the primary 
objective for the species' recovery efforts, preferably including a 
population at Manse Spring. The species is less likely to be threatened 
simultaneously at three or more separate sites than at a single 
location. The Recovery Plan also stated that the species could be 
considered for reclassification to threatened status when each of the 
three populations contained at least 500 adults for 3 years, and each 
habitat was free of immediate and potential threats. Poolfish could be 
considered for delisting if the three populations continued to exceed 
500 individuals for an additional 3 years after reclassification.
    All three transplanted populations of poolfish reproduced 
successfully and thrived in their new habitats, and data indicated that 
these transplanted populations had maintained a minimum of 500 
individuals between 1986 and 1993 (Nevada Department of Wildlife, NDOW, 
1988a, 1988b; Sjoberg 1989; Heinrich 1991a, 1991b, 1993). With the 
three populations stable and secure on Federal and State lands, we 
published a proposed rule to downlist the poolfish from endangered to 
threatened status on September 22, 1993 (58 FR 49279).
    However, soon after the publication of the proposed rule, we 
learned that the Nevada Division of State Parks (NDSP) would receive 
funding for a project to drain and dredge accumulated sediment from the 
irrigation reservoir at the State Park to restore the reservoir's water 
storage capacity. We informed the NDSP of the proposed project's 
potential to adversely affect the poolfish population residing in the 
reservoir, and that the NDSP must obtain an incidental take permit from 
us, pursuant to section 10(a)(1)(B) of the Endangered Species Act of 
1973, as amended (Act) (16 U.S.C. 1531 et seq.). Further action on the 
proposed rule was halted as the NDSP developed a habitat conservation 
plan (HCP) to apply for the permit.
    In 1995, the NDSP acquired a section 10(a)(1)(B) permit from us for 
the proposed modifications and future operation and maintenance of the 
irrigation reservoir at the State Park as described in the HCP. The 
permit remains in effect until the year 2025. Modifications to the 
reservoir in 1995 were completed without adversely affecting the 
poolfish population. Based on information from annual surveys utilizing 
mark and recapture methods, as well as informal visual surveys, the 
population remains stable at the State Park, and is currently the 
largest population of poolfish, estimated at 16,775 individuals (95 
percent confidence interval) in 2003 (NDOW in litt. 1997, 2001b, 2001c, 
2002a, 2002b; NDOW 1999, 2000, 2001; B. Hobbs, NDOW, pers. comm. 2002; 
B. Hobbs, NDOW, pers. comm. 2003).
    In the late 1990s, the population of poolfish at Corn Creek Springs 
was lost to illegally introduced nonnative crayfish (NDOW 1999). The 
last three poolfish were found at Corn Creek Springs during summer 
surveys in 1998 and no other poolfish were captured during surveys in 
subsequent years (NDOW 1999, 2000). A new, isolated refugium for the 
poolfish was built at Corn Creek Springs in 2002. Thirty adult poolfish 
from the State Park population were introduced into the refugium in 
June 2003, with visual surveys in July 2003 revealing eight young in 
the refugium (NDOW in litt. 2003a). Another 30 adult poolfish were 
added to the refugium from the State Park population in August 2003, 
with additional introductions to the refugium planned for the near 
future (NDOW in litt. 2003a). The third poolfish population at the 
Shoshone Ponds Natural Area has historically remained stable since the 
1980s with only natural population fluctuations affecting its status 
(NDOW in litt. 2003b). However, surveys in 2003 indicated a significant 
decrease in the population to less than 1,000 individuals. The cause 
for the decline is unknown and is currently being investigated (NDOW, 
in litt. 2003b).

Previous Federal Action

    On March 11, 1967, the Pahrump poolfish (as the Pahrump killifish) 
was listed as endangered under the Endangered Species Preservation Act 
of 1966 (16 U.S.C. 668aa(c)). The species retained its endangered 
status with the passage of the Act. The Recovery Plan for this species 
was completed in 1980. On September 22, 1993, we proposed to reclassify 
the Pahrump poolfish from endangered to threatened status (58 FR 
    Other Federal actions include section 7 consultations with the DNWR 
and the BLM regarding the potential effects of various actions on the 
poolfish populations within their respective jurisdictions. 
Consultations with the DNWR have included projects with actions having 
short-term adverse effects to the poolfish population at Corn Creek 
Springs, but with long-term benefits. These include chemical 
eradication of competing mosquitofish, and mechanical and chemical 
removal of emergent vegetation to preserve pond integrity. The BLM has 
consulted with us on the management of the Shoshone Ponds Natural Area, 
as well as prior to authorizing transfer of public lands in adjacent 
areas into private ownership under the Desert Land Entry Act. This act 
allows individuals to reclaim, irrigate, and cultivate arid and 
semiarid public lands. We have also issued several recovery permits 
under section 10(a)(1)(A) of the Act to the NDOW and various academic 
institutions, authorizing take of the species for tasks identified in 
the Recovery Plan. Finally, we have previously allocated funds to the 
NDOW for conducting surveys of each poolfish population and may 
continue to do so in the future as funds are available, under section 6 
of the Act.

Summary of Comments

    With publication of the proposed rule on September 22, 1993, we 
requested that all interested parties submit factual reports, 
information, and comments that might contribute to the development of 
the final downlisting decision. We contacted appropriate State and 
Federal agencies, County and city governments, scientific organizations 
and authorities, and other interested parties, and requested them to 
comment. Following the publication of the proposed rule, we received 
two comments: one from the

[[Page 17385]]

NDOW and the other from an individual, both supporting the 
reclassification, and neither raised any additional concerns.

Summary of Factors Affecting the Species

    Section 4 of the Act 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 five factors described in section 4(a)(1). These factors, and their 
application to the Pahrump poolfish, are as follows:

A. The Present or Threatened Destruction, Modification, or Curtailment 
of Its Habitat or Range

    Current Range: Three separate populations of poolfish currently 
exist; however, only one is considered stable. Additionally, none of 
these populations currently occurs at Manse Spring, its native habitat. 
Establishing a population of poolfish at Manse Spring was identified as 
a high-priority objective of the Recovery Plan. However, recent 
residential development in and around Manse Ranch continues to modify 
the native habitat, and future residential and commercial development 
in the Pahrump Valley may limit the available water resources and 
preclude the opportunity to re-establish a poolfish population in this 
    Excessive Groundwater Withdrawals: The most critical threat to the 
poolfish has historically been the destruction of habitat through 
groundwater withdrawals, as demonstrated by the desiccation of the only 
native habitat of the species. Adequate, reliable water sources are 
necessary to ensure that currently occupied ponds provide suitable 
habitat for the poolfish. Thus, long-term declines in spring flows due 
to groundwater pumping from areas surrounding existing poolfish habitat 
remain a threat to all the populations. Threats to water sources 
necessary for poolfish habitat have been minimized to the extent 
possible by the managing Federal and State agencies. For example, we 
filed for, and received, vested water rights at Corn Creek Springs from 
the State of Nevada that will ensure the water supply for the poolfish 
population at that location. In addition, the NDOW and the NDSP hold 
State appropriative water rights to the springs supporting the habitats 
at Shoshone Ponds Natural Area and the State Park, respectively.
    In the past, groundwater withdrawals were mainly done for 
agricultural activities. However, the present demand on limited water 
sources is to accommodate the growing human population and development 
in the arid desert of southern Nevada. The annual population growth in 
southern Nevada has been 7 percent per year since 1910, whereas growth 
in the United States during the same period has averaged only 1 percent 
per year (Southern Nevada Water Authority (SNWA) 2002). Southern Nevada 
is primarily reliant on the Colorado River for most of its water; 
however, groundwater is a critical component of the area's water 
resources, mainly to meet peak water demands during the hot summer 
(SNWA 2002). Secured water rights at poolfish habitats currently 
provide available groundwater resources to support the species. 
However, all of the groundwater rights held by local water agencies are 
currently not being utilized, and these agencies are exploring use of 
these rights as future options to meet continued demand (SNWA 2002). It 
is likely that the threat of significantly reduced, and limited, water 
sources caused by pressures exerted on the groundwater system to 
accommodate extensive population growth and development in southern 
Nevada could threaten the future existence of the poolfish.

B. Overutilization for Commercial, Recreational, Scientific, or 
Educational Purposes

    The Pahrump poolfish is a nongame fish, and no commercial or 
recreational use of the species has been documented, nor is it 
anticipated. Scientific interest in this species has been limited to 
activities associated with tasks identified in the Recovery Plan. 
Section 10 of the Act allows for the issuance of permits for research, 
rehabilitation, and propagation. We issue recovery permits authorizing 
activities identified in the Recovery Plan, provided these activities 
do not jeopardize the continued existence of the poolfish.
    Since Corn Creek Springs and Shoshone Ponds Natural Area are open 
to the public without daily oversight by agency personnel, it is 
difficult for us and the BLM to protect the ponds from illegal human 
actions that may adversely affect the poolfish and their habitat. Most 
legal human activities in these areas, such as recreational fishing, 
have not been and are not a threat to the poolfish. Vandalism was 
historically a significant problem at Shoshone Ponds Natural Area. The 
initial introduction of poolfish to those ponds from Manse Spring was 
lost to vandalism in 1974 when the water source was intentionally 
turned off (M. Barber in litt. 1987). Vandalism continues to be a minor 
threat to the poolfish in this location, given that public access to 
the site is not monitored on a daily basis (B. Hobbs, pers. comm., 

C. Disease or Predation

    The remaining populations of poolfish possess low numbers of common 
external fish parasites (Heckmann 1987, 1988); however, neither these 
parasites nor any diseases are currently a threat to the poolfish.
    The effect of predation by the nonnative bullfrog on the poolfish 
population at Corn Creek Springs has been investigated. Analyses of 
bullfrog stomach contents indicated that bullfrog predation on poolfish 
is minimal (D. Withers, NDOW, in litt. 1985, 1986, 1988; J. Heinrich, 
NDOW, in litt. 1991). Bullfrogs also persist and predate on poolfish at 
the State Park, but do not represent a significant threat to the 
overall population (Heinrich 1991a; B. Hobbs, pers. comm., 2002).
    In 1975, the population of poolfish at Corn Creek Springs 
experienced a rapid reduction as a result of unauthorized introduction 
of nonnative mosquitofish. Close coordination between our agency, State 
agencies, and academic institutions resulted in the eradication, by 
chemical means, of the mosquitofish to alleviate competitive pressures 
on the poolfish (Selby 1977). For years afterwards, the poolfish at 
Corn Creek Springs remained a healthy and stable population.
    The stability of this population was again threatened when 
nonnative crayfish were illegally introduced into the ponds at Corn 
Creek Springs. Surveys first noted the presence of crayfish in 1993, 
and thereafter the poolfish population rapidly declined (NDOW 1999). 
Despite attempts to eliminate the crayfish, the poolfish population was 
extirpated by 1999. Nonnative common goldfish were first discovered in 
1998 at Corn Creek Springs (NDOW 1999). The presence of the competing 
and predatory goldfish may have compounded the problem of an already 
depleted population of poolfish, possibly contributing to the demise of 
the population that year. Efforts by the DNWR, the NDOW, and volunteers 
to eradicate nonnative crayfish from Corn Creek Springs have been 
unsuccessful (NDOW in litt. 2001a). Thus, a new, isolated refugium for 
the poolfish was built at Corn Creek Springs in 2002 with introductions 
to the refugium from the State Park in June and July of 2003 (see 
Transplant History above) (NDOW in litt. 2003a).
    Illegal introductions of nonnative aquatic species to the habitats 

[[Page 17386]]

poolfish have occurred historically and continue to pose the most 
significant current threat to the existence of this species. Currently, 
the populations at the State Park and Shoshone Ponds Natural Area have 
not been significantly affected by nonnative aquatic species. However, 
the recent loss of the population at Corn Creek Springs illustrates 
that the poolfish is vulnerable to extinction as a result of predation 
by aggressive, aquatic nonnative species. The introduction of nonnative 
species to the populations of poolfish at the State Park or Shoshone 
Ponds Natural Area could impose irreparable consequences.

D. The Inadequacy of Existing Regulatory Mechanisms

    Federal Protection: Upon being listed under the Act, the poolfish 
immediately benefitted from a Federal regulatory framework. This 
framework includes prohibition of take, which is defined broadly under 
the Act to include killing, injuring, or attempting to kill or injure; 
prohibition of habitat destruction or degradation if such activities 
harm individuals of the species; the requirement that Federal agencies 
ensure their actions will not likely jeopardize the continued existence 
of the species; and the requirement that we develop and implement a 
recovery program for the species. Poolfish continue to be protected by 
the provisions of the Act.
    Additionally, as previously discussed, the population of poolfish 
at the State Park will be conserved under the provisions of the section 
10(a)(1)(B) permit issued by us to the State for its HCP. This permit 
remains in effect until the year 2025.
    The sites where the poolfish currently resides have no connection 
to a navigable water. Therefore, it is unlikely that section 404 of the 
Clean Water Act of 1972, as amended, administered by the U.S. Army 
Corps of Engineers, will provide any regulatory protection for this 
    State Regulations: The State of Nevada classifies the poolfish as a 
fully protected fish species, further classified as endangered under 
Chapter 503.065 of the Nevada Administrative Code (2002). The State 
prohibits the capture, removal, or destruction of any protected species 
at any time, by any means, except under a special permit issued by the 
NDOW under Chapters 503.584-503.589 of the Nevada Revised Statutes 
(NRS) (2002). The Nevada Natural Heritage Program also ranks the 
poolfish as S1, meaning that in Nevada it is considered critically 
imperiled due to extreme rarity, imminent threats, and/or biological 
factors. However, this designation provides no legal protection in 
    A Nevada legislative finding in 1969 recognized the serious losses 
of native fish and wildlife in the State and provided a method for the 
State to conserve, protect, restore, and propagate selected species of 
native fish and wildlife and their habitats (NRS 2002). This finding 
and subsequent amendments included the authority for the State's Board 
of Wildlife Commissioners and State agencies it governs, specifically 
NDOW, to manage land in accomplishing the objectives of the program to 
conserve native fish and wildlife, including conserving, protecting, 
and assisting in propagating the poolfish.
    The NDOW is a cooperating partner with us for the ongoing 
management efforts to conserve this native fish species. In light of 
the events that have occurred since we proposed to reclassify the 
poolfish, the NDOW fully supports the current action to withdraw the 
proposed rule (Jon Sj[ouml]berg, NDOW, pers. comm. 2003).

E. Other Natural or Manmade Factors Affecting Its Continued Existence

    The low numbers of poolfish in its isolated habitats naturally make 
it vulnerable to risks associated with small, restricted populations. 
The elements of risk that are amplified in very small populations 
include: (1) Random demographic effects (e.g., skewed sex ratios, high 
death rates, or low birth rates); (2) the effects of genetic drift 
(random fluctuations in gene frequencies) and inbreeding (mating among 
close relatives); (3) natural catastrophes (floods, fires, droughts, 
etc.) at random intervals; and (4) deterioration in environmental 
quality (Shaffer 1987). However, the poolfish were believed to have 
been isolated for over 20,000 years in the Pahrump Valley (Soltz and 
Naiman 1978), and this natural evolutionary factor is currently an 
insignificant threat when compared with the historical modification of 
its natural habitat, introductions of nonnative, aquatic predators in 
its transplanted habitats, and reduced and limited water supplies.

Summary of Findings

    In developing this notice, we carefully assessed the best 
scientific and commercial information available regarding the past, 
present, and future threats faced by the Pahrump poolfish. Events 
subsequent to the proposed rule published in 1993 resulted in the 
extirpation of the poolfish population at Corn Creek Springs, although 
a small number of poolfish have recently been successfully introduced 
back into a new isolated refugium at Corn Creek Springs. Surveys in 
2003 showed a significant decline in the population at Shoshone Ponds 
Natural Area, with the cause currently unknown. Therefore, only the 
State Park poolfish population remains stable. Thus, one of the main 
objectives for downlisting the species in the Recovery Plan, which is 
to have three stable populations of poolfish, has not been met.
    This species was historically threatened by habitat destruction and 
degradation, particularly from groundwater pumping which led to 
extirpation from its only known natural habitat. Currently, we remain 
concerned that this species is threatened by potential introductions of 
nonnative aquatic predators, and habitat destruction and loss due to 
reduced and limited water supply for the poolfish as a result of 
demands on limited water sources to accommodate extensive population 
growth and development in the arid desert of southern Nevada.
    Because the Pahrump poolfish occurs in only one stable population, 
and because all the poolfish populations are subject to various 
immediate, ongoing, and future threats as outlined above, we find that 
this species continues to be in imminent danger of extinction. 
Therefore, the poolfish meets the Act's definition of endangered and 
warrants continued protection as endangered under the Act. Threatened 
status would not accurately reflect the diminished status and threats 
to this species. Based upon the findings documented in this notice, we 
are hereby withdrawing the proposed rule published on September 22, 
1993 (58 FR 49279), that proposed to reclassify the Pahrump poolfish 
from endangered to threatened.

References Cited

    A complete list of all references cited herein is available upon 
request from our Southern Nevada Field Office (see ADDRESSES section).


    The primary author of this notice is Amy LaVoie (see ADDRESSES 


    The authority for this action is the Endangered Species Act of 
1973, as amended (16 U.S.C. 1531 et seq.).

    Dated: March 8, 2004.
Marshall P. Jones, Jr.,
Deputy Director, Fish and Wildlife Service.
[FR Doc. 04-7412 Filed 4-1-04; 8:45 am]