(DRAFT) - Taxonomy
Species CHUB, ROUNDTAIL, PAHRANAGAT
Species Id ESIS251009
Date 14 MAR 96
TAXONOMY
NAME - CHUB, ROUNDTAIL, PAHRANAGAT
OTHER COMMON NAMES - CHUB, ROUNDTAIL, PAHRANAGAT;BONYTAIL, PAHRANAGAT; CHUB, BONYTAIL, NEVADA; GILA, COLORADO, WHITE and RIVER
ELEMENT CODE -
CATEGORY - Fish
PHYLUM AND SUBPHYLUM - CHORDATA,
CLASS AND SUBCLASS - OSTEICHTHYES,
ORDER AND SUBORDER - CYPRINIFORMES,
FAMILY AND SUBFAMILY - CYPRINIDAE,
GENUS AND SUBGENUS - GILA,
SPECIES AND SSP - ROBUSTA, JORDANI
SCIENTIFIC NAME - GILA ROBUSTA JORDANI
AUTHORITY -
TAXONOMY REFERENCES -
COMMENTS ON TAXONOMY -
Pahranagat Roundtail Chub
Gila robusta jordani Tanner, 1950
KINGDOM: Animal GROUP: Fish
PHYLUM: Chordata CLASS: Osteichthyes
ORDER: Cypriniformes FAMILY: Cyprinidae
A somewhat elongated minnow, to 10 inches in length, with a
depressed head, slightly elevated back, and blotches on the larger
adults. Depth of caudal peduncle is about 1/3 of the body length.
Caudal fin is forked, dorsal fin originates slightly behind the
pelvic fin and middle caudal rays are less than 1/2 the length of
the rays in the upper lobe of the caudal fin. Dorsal and anal fins
have 9 fin rays. Pharyngeal teeth are 2,5-4,2. There are about
89-94 scales in the lateral line.
The Paharanagat roundtail chub was originally described by Vasco
Tanner as Gila jordani (17). Since then it has generally been
referred to as Gila robusta jordani (06,12). Common names used for
the subspecies include: Pahranagat bonytail, Nevada bonytail chub,
and Colorado White River gila. Type specimens are in the
Natural History Museum of Brigham Young University. Additional museum
specimens are at the University of Michigan Museum of Zoology and the
Taxonomy - 1 (DRAFT) - Taxonomy
Species CHUB, ROUNDTAIL, PAHRANAGAT
Species Id ESIS251009
Date 14 MAR 96
ichthyology collection at Arizona State University. The subspecies
is illustrated by Tanner (17) and La Rivers (12).
Taxonomy - 2 (DRAFT) - Status
Species CHUB, ROUNDTAIL, PAHRANAGAT
Species Id ESIS251009
Date 14 MAR 96
STATUS
Coded Status
E: Federal Endangered
COMMENTS ON STATUS -
U.S. STATUSES AND LAWS:
The Pahranagat roundtail chub (Gila robusta jordani) has been
designated Endangered pursuant to the Endangered Species
Act of 1973 (50 CFR 17.11; P.L. 93-205, 87 Stat. 884; 16 U.S.C.
1531-1540), as amended. The subspecies has this status wherever found
including the State of Nevada.
This subspecies is protected by the Lacey Act (P.L. 97-79, as
amended; 16 U.S.C. 3371 et seq.) which makes it unlawful to import,
export, transport, sell, receive, acquire, or purchase any wild animal
(alive or dead including parts, products, eggs, or offspring):
(1) in interstate or foreign commerce if taken, possessed,
transported or sold in violation of any State law or
regulation; or
(2) if taken or possessed in violation of any U.S. law,
treaty, or regulation or in violation of Indian tribal law.
It is also unlawful to possess any wild animal (alive or dead
including parts, products, eggs, and offspring) within the U.S.
territorial or special maritime jurisdiction (as defined in
18 U.S.C. 7) that is taken, possessed, transported, or sold in
violation of any State law or regulation, foreign law, or Indian
tribal law.
RESPONSIBLE FEDERAL AGENCIES:
USFWS -Responsible for the management/recovery, listing, and
law enforcement/protection of this species.
All Federal agencies have responsibility to ensure that any
action authorized, funded, or carried out by that agency is not likely
to jeopardize the continued existence of the species or result in the
destruction or adverse modification of Critical Habitat (50 CFR 402),
and to utilize their authorities to carry out programs for the
conservation of the species.
STATE STATUSES AND LAWS:
STATE: Nevada
DESIGNATED STATUS: Endangered
ADMINISTRATIVE AGENCY: Nevada Department of Wildlife.
STATE STATUTE: Nev. Rev. Stat. 501.181, 501.351, 503.584,
503.585, 503.587, 503.588, and 503.589.
Status - 1 (DRAFT) - Status
Species CHUB, ROUNDTAIL, PAHRANAGAT
Species Id ESIS251009
Date 14 MAR 96
INTERNATIONAL STATUSES, TREATIES, AND AGREEMENTS:
The Pahranagat roundtail chub is listed as Endagered in the
IUCN Red Book (1977 edition).
ECONOMIC STATUSES:
None.
70/08/25:35 FR 13519/13520 - Proposed List/Endangered (1969 Act).
70/10/13:35 FR 16047 - Listed as Endangered.
79/05/21:44 FR 29566/29577 - Five Year Review.
85/07/22:50 FR 29901/29909 - Five Year Review.
Status - 2 HABITAT ASSOCIATIONS
HABITAT - AQUATIC
INLAND AQUATIC
LAND USE -
Cropland and Pasture
Herbaceous Rangeland
Shrub and Brush Rangeland
Streams and Canals
NATIONAL WETLAND INVENTORY CODES
NWI NWICLS NWIMOD NWISPEC
Riverine, lower perennial SB4
Riverine, lower perennial SB3
Riverine, lower perennial SB2
Riverine, lower perennial SB1
COMMENTS ON HABITAT ASSOCIATIONS -
Hardy (09,10) found Gila robusta jordani only in the outflow
of Ash Springs. Courtenay (01) reported that the Ash Springs
recreational (swimming) pool was drained and cleaned during Summer,
1983. Subsequently, Gary Scappetone and Don Sada of the U.S. Fish and
Wildlife Service noted adult Pahranagat roundtail chubs in the
recreational pool of Ash Springs. Perhaps they entered the pool while
the pool was being drained.
The outflow of Ash Springs flows in its natural stream course for
about 2,250 meters prior to being confined to a cement irrigation
ditch (this is not suitable habitat for species survival, but the
occasional stray fish may be found in this area). The Pahranagat
roundtail chub is usually quite rare in the upper 1,962 meters,
maintaining good numbers of adults only in a single microhabitat in
the lower portion of the natural channel (09).
Hardy describes the habitat in the outflow of Ash Springs in
detail. The upper 1,962 meters of the outflow stream is bordered by
riparian vegetation consisting of ash (Fraxinus), willow (Salix),
grape (Vitis), mesquite (prosopis), and cottonwood (Populus). These
species provide considerable aquatic cover. Many understory plants
occur along the stream margin as well. Away from the riparian
corridor the vegetation consists of pasture grasses, weeds and some
few bushes. In this upper section the stream substrate is firm sand
and gravel in the swifter portions with mud and silt dominating
substrates in the slower portions. Runs, pools, and riffles comprise
about 87%, 6% and 7%, respectively, of the available habitat. Mean
width is about 4 meters. Gradient in the upper section is higher than
in the lower section.
The lower section of the natural channel from about 1,962-2,250
meters below Ash Springs is a generally broad, straight channel.
There are scattered dense stands of willow and grape along the stream
margin with some ash and cottonwood. Again, root projections, fallen
branches (and logs) and overhanging branches provide aquatic cover.
The substrate is sand, silt and mud. Runs and pools comprise about
92% and 8% of the available habitat, respectively. There are no
riffles in this segment. Stream gradient is low, banks are not
well-defined and the channel is about 6 meters in width.
Adult Pahranagat roundtails were almost entirely restricted to a
single microhabitat in this egment of the stream for most of the year
from January, 1979 to September, 1981. The microhabitat consisted of
Habitat Associations - 1 a large pool with overhead and submerged cover adjacent to a deeply
undercut bank. Maximum velocity measured in the microhabitat was
0.18 m/sec., with a mean velocity of 0.03 m/sec.(+/-0.23). Young
chubs were observed throughout the lower section of the stream, but
also reached their greatest densities in this one pool.
The lower reach routinely held 37-45 adult fish throughout the
two-year study period, except in February and March when adult fish
were absent. Juvenile chub (30-100 mm TL) used this reach from March
through September, reaching a maximum population of about 250 fish.
Kanim Parker (20) reports juvenile fish from the lower reach in May,
1985. The relative scarcity of deep, slow run/pool habitats with
associated cover may impose some limitation on population size in this
last remaining habitat available to the species.
The following physical and chemical conditions were measured in
Pahranagat roundtail chub habitat by Hardy (09) and Deacon (04).
Temperature 15-30 deg Celsius; dissolved oygen 5.9-6.4 mg/l.; pH 8.1;
hardness 184-234 mg/l.; alkalinity 160-170 mg/l.; nitrate
102-158.5 ug/l.; sulfate 32-42.2 mg/l.; conductivity 468-499 ohms/cm;
turbidity .87-1.27 N.T.U.. Temperature throughout much of the summer
remains above 27 deg Celsius throughout the availiable habitat.
Temperature tolerance for Gila robusta jordani is not known;
however, data is available for the closely related Gila robusta from
Moapa River (14,15). The latter species showed a final perferendum at
about 24 deg Celcius; Critical Thermal Max. (CTM) for fish acclimated
to 10, 15 and 25 deg Celsius was, respectively, 27.9 (+/- 0.22),
32.3 (+/- 1.39) and 36.41 (+/- 0.66). It seems probable that
G. r. jordani may be confined to waters that, for much of the year,
remain above preferred temperature.
Habitat Associations - 2 (DRAFT) - Food Habits
Species CHUB, ROUNDTAIL, PAHRANAGAT
Species Id ESIS251009
Date 14 MAR 96
FOOD HABITS
TROPHIC LEVEL -
OMNIVORE
LIFESTAGE FOOD FOOD PART
General Arthropods
General Detritus
General Algae
Food Habits - 1 (DRAFT) - Environment Associations
Species CHUB, ROUNDTAIL, PAHRANAGAT
Species Id ESIS251009
Date 14 MAR 96
ENVIRONMENTAL ASSOCIATIONS
G = General A = Adult
LIM = Limiting RA = Resting Adult
J = Juvenile FA = Feeding Adult
RJ = Resting Juvenile BA = Breeding Adult
FJ = Feeding Juvenile P = Pupae
L = Larvae E = Egg
RL = Resting Larvae
FL = Feeding Larvae
LIFESTAGE ENVIRONMENTAL ASSOCIATIONS
G Aquatic Features: Pool areas
G Aquatic Features: Springs [flowing]
G Terrestrial Features: Downed logs
G
Environment Associations - 1 (DRAFT) - Life History
Species CHUB, ROUNDTAIL, PAHRANAGAT
Species Id ESIS251009
Date 14 MAR 96
LIFE HISTORY
FOOD HABITS:
Hardy (09) made the following observations of food habits of
G. r. jordani by observing fish in the outflow of Ash Springs, while
various food items were released to float past the adults.
"Although aquatic Ephemeropteran, Trichopteran, Coleopteran and
Dipteran larvae were exposed to the adult chubs, none were ingested.
In fact, only on one occassion was any invertebrate taken and that was
an adult aquatic dipteran. In general, both adult and larvel insects,
whether aquatic or terrestrial, were ignored. Algae, on the other
hand was readily taken on all occasions, with Spirogyra more
vigorously pursued than Comsopogon or other algal species. These
results are consistent with data for adult Gila robusta seminuda from
Virgin River. Cross (1978) found that filamentous algae comprised
90% of the volume of the gut contents. Terrestrial and aquatic
insects and amphipod larvae were next in abundance. Other
investigations have shown that Gila robusta in the Colorado River
drainage are generally omnivorous (12,16,18,13,02). Vanicek and
Kramer (18) note that young chubs are primarily insectivorous, feeding
on Chironomidae larvae and Ephemeroptera nymphs, but as the animals
mature they shift their dietary preference to include aquatic and
terrestrial insects and plant material. This same pattern has been
observed in Gila robusta seminuda from the Virgin River (07).
Preliminary analysis of Gila robusta ssp. from the Moapa River also
shows this dietary change between young and adult chubs (19).
In the outflow of Ash Spring, young chubs must make this
transition in late fall or early winter at a time when most of the
algae has disappeared. This may impose a severe limitation of
recruitment into the adult population. The fact that the adult
population is stable at about 40 individulas suggests that 40 may be
about the winter carrying capacity for the system."
Greger and Deacon (08) present the following analysis of stomach
contents of closely related subspecies in the Virgin River.
Adult diet of Gila robusta seminuda in the Virgin River (mean percent
volume) (08):
Item: February June September December
Debris detritis 36 35 29 16
Enteromorpha ssp. 8
Cladophora ssp. 5 50 14 12
Spirogyra 6 6 27 3
Insecta 8 2 1
Drift animals 8 6 36
Ephemeroptera 2
Anisoptera 25
Taenionema ssp. 9
Chironomid larvae 19 7 1
Simuliid larvae 7 2
Simuliid pupae 6
Mayfly adult 6
Life History - 1 (DRAFT) - Life History
Species CHUB, ROUNDTAIL, PAHRANAGAT
Species Id ESIS251009
Date 14 MAR 96
Ceratopogonidae 1
Number Examined: 20 4 30 6
HOME RANGE/TERRITORY:
The Pahranagat bonytail is not territorial. Adults do congregate
in deep water with slow current in areas where cover exists. They
remained in one habitat for most of the time over a two-year period
(09). This may have been a consequence of no other suitable habitat
being available to them.
PERIODICITY:
The adult population almost continuously occupied a single,
preferred habitat from January, 1979 to September 1981. They left the
area only in February and March. This suggests seasonal spawning
(09).
MIGRATION PATTERNS:
The species is not migratory.
COVER/SHELTER REQUIREMENTS:
Pahranagat roundtail chub adults appear to exhibit strong
preference for deep, slow pools with associated cover (09,10).
Observations made by Deacon (04), subsequent to Hardy's (09) study,
indicate that adults occurring in more upstream habitats also select
deep pools were cover is present. Cover in the outflow of Ash Spring
consists primarily of fallen logs or branches.
REPRODUCTIVE SITE REQUIREMENTS:
Reproduction of the Pahranagat roundtail chub has not been
observed. It appears to leave sheltered pools for reproduction, but
where it goes is unknown (09).
REPRODUCTIVE CHARACTERISTICS:
In the outflow of Ash Spring the breeding season may occur in
February and March when adults leave their sheltered pool (09). Hardy
(09) also points out that this period coincides with annual thermal
minimum temperatures and that when adults returned in April, some were
in breeding colors. Juveniles (30-100 mm TL) were present in the
study area from March through September and disappeared rapidly from
the population during October through January. Adults, therefore,
appear to live through at least two winters prior to spawning (09).
PARENTAL CARE:
The species probably provides no parental care.
POPULATION BIOLOGY:
Hardy (09) indicates that in the lower reach of the outflow of
Ash Springs about 40 adults live through winter. Apparently, spawning
occurs elsewhere in February and March. Young appear in March,
occupy a greater diversity of habitats but tend to prefer the deep
pool area inhabited by adults. Total population size in the lower
portion of the Ash Springs outflow was estimated to reach about 250
Life History - 2 (DRAFT) - Life History
Species CHUB, ROUNDTAIL, PAHRANAGAT
Species Id ESIS251009
Date 14 MAR 96
fish during summer and fall to about 125 during January.
Factors limiting population size appear to include limitation
of suitable habitat (01,09), predation or competitive pressure from
exotic species (01,03,04,05,09), food limitation exacerbated by the
problem of making the transition from the more insectivorous juveniles
to the more herbivorous adult (07,08,09), and availability of
preferred habitat at prefered temperature (09,14,15).
The occurrence of juvenile fish in intermittent pools downstream
from the main population center may be a consequence of temperature
preference lower than that available anywhere in the remnant of the
natural channel that serves as the only permanent habitat for the
species.
SPECIES INTERRELATIONSHIPS:
No definite interrelationships have been established between
Pahranagat roundtail chubs and other species. Hardy (09) suggests
that the introduced snail, Melanoides, may prey on eggs. Spatial
competition appears most likely with the speckled dace (Rhinichthys
osculus) which appears to feed on many of the same foods utilized by
juvenile chubs (09,10). Food overlap does occur between adult chubs
and the exotic Convict chichlid (Cihclasoma nigrofasciatum) and
shortfin molley (Poecila "sphenops complex") (09).
OTHER LIFE HISTORY DESCRIPTORS:
None.
Life History - 3 (DRAFT) - Management Practices
Species CHUB, ROUNDTAIL, PAHRANAGAT
Species Id ESIS251009
Date 14 MAR 96
MANAGEMENT PRACTICES
RESULT MANAGEMENT PRACTICE
Beneficial Developing/maintaining stream structures
Beneficial Land Acquisition
Beneficial Stocking captive-reared wild-strain animals
Beneficial Controlling/Removing Exotic Vertebrates
Adverse Predation
Existing Predation
Adverse Irrigating
Existing Irrigating
Adverse Competition
Existing Competition
Adverse Exotic/Feral/Introducted Species
Existing Exotic/Feral/Introducted Species
Adverse
Existing
COMMENTS ON MANAGEMENT PRACTICES -
The present status of the Pahranagat roundtail chub (Gila
robusts jordani) is primarily due to habitat loss and predation and
competition with introduced exotic species. Tanner (17) in 1950
noted that "...under the present method of dealing with the water
from these springs I surmise that they may, in the future, become
extinct". Courtenay (01) provides an account of water use in
Pahranagat Valley since about 1850. This suggests that Tanner (17)
probably referred largely to irrigation diversion for agricultural
use. In addition, introduction of exotic species since 1959 has added
to the problems of survival experienced by Pahranagat roundtail chubs
(01,03,04,05,09,15).
Hardy (09) states that the food utilization patterns
(competition) by exotic/introduced species such as Cihclasoma
nigrofasciatum (Convict cichlid) may be limiting to both juvenile and
adult chubs. In addition, younger fish face the threat of predation
from the Convict cichlid and mosquitofish (Gambusia affinis).
Cichlids and molles show food overlap with adult chub and the overlap
between juvenile chub and cichlids and mosquitofish is assumed by
Hardy (09) to be very high. Deacon (04) also suggests that the
introduced tropical snail Melanoides may prey on fish eggs. Hardy
(09) suggested that viviporous mollies and mosquitofish have
reproductive advantage over oviparous fishes such as chub due to
their ability to reproduce throughout the year. He sums up his
argument by stating, "In summary, the exotic/introduced species
appear to have an ecological advantage over the native species in
their ability to exploit the available habitat in terms of
temperature, space and food".
Courtenay (01) gave no reason for the extirpation
of this species from Crystal Springs but did point out that largemouth
bass were introduced into the system by the Nevada Department of
Wildlife in 1959 and that G. r. jordani was absent from the system in
1961.
Management Practices - 1 (DRAFT) - Management Practices
Species CHUB, ROUNDTAIL, PAHRANAGAT
Species Id ESIS251009
Date 14 MAR 96
Presently the Pahranagat roundtail chub occurs only in Ash
Springs and about 2,250 meters of its outflow. Below that point the
flow is confined to a concrete irrigation ditch from which water can
be diverted for use on crops and pasture. During summer 1985, Donna
Withers of Nevada Dept. of Wildlife discovered some pools below the
irrigation ditch that contained small Pahranagat roundtail chubs.
These fish were captured and sent to the Dexter National Fish Hatchery
in New Mexico, before the pools dried up. This phenomenon may happen
virtually ever summer. The subspecies thus appears to be presently
threatened by having lost most of its stream habitats, adverse
consequences of interaction with exotic fishes and snails, and loss
of young to downstream intermittent habitats.
APPROVED PLAN:
U.S. Fish and Wildlife Service. 1986. The Pahranagat Roundtail Chub
Recovery Plan. U.S. Fish and Wildl. Serv., Portland, OR., 46 pp.
The primary objective of the recovery plan for the Pahranagat
roundtail chub is to reduce the potential for extinction by restoring
populations in historic habitats (through a captive breeding program),
completing life history and habitat research, then rehabilitating
habitats and reestablishing populations, and securing habitats from
future threats. Declassifying to Threatened status could be
considered when three populations are established and two of the
three are secured at the minimal, self-sustaining size (to be
determined) for at least three years without future threats
developing. Delisting can occur when three populations have been
secured and habitats have been maintained without any threats over a
five year period.
The recovery activities necessary to acheive the primary
objectives are:
1. Establish and maintain hatchery populations for captive breeding
and reintroduction into historic habitats;
2. Determine species ecology, eg. preferred habitat, reproduction
parameters, food preferences, population dynamics, factors
affecting population dynamics, and effects of habitat alteration;
3. Secure and reestablish species' ecosystems by: a) identifying
habitat and populations, b) securing habitats (i.e., land
acquisition), c) restoring or enhancing habitat (i.e., revegetation
and rehabilitation and/or stream bank/channel modification), d)
preparing habitat management plans, e) removing predatory (this
may include native species) and exotic species, and f) preventing
reintroduction of exotics;
4. Reintroduce into restored habitats;
5. Monitor existing and reestablished populations;
6. Enforce Federal laws and state regulations to protect the species;
and
7. Implement a public information and education program.
Management Practices - 2 (DRAFT) - References
Species CHUB, ROUNDTAIL, PAHRANAGAT
Species Id ESIS251009
Date 14 MAR 96
References
***** REFERENCES FOR ALL NARRATIVES EXCEPT N-OCCURRENCE *****
01 Courtenay, W.R., J.E. Deacon, D.W. Sada, R.C. Allan, and G.L.
Vinyard. 1985. Comparative status of fishes along the course of
the pluvial White River, Nevada. S.W. Nat. [In press.]
02 Cross, J.N. 1976. Status of the native fish found in the Moapa
River, Clark County, Nevada. Trans. Am. Fish. Soc. 105(4):503-508.
03 Deacon, J.E. 1979. Endangered and threatened fishes of the West.
Gt. Basin Nat. Mem. 3:41-64.
04 Deacon, J.E., T.B. Hardy, J. Landye, J. Pollard, W. Taylor, and
P. Greger. 1980. Environmental analysis of four aquatic habitats
in east-central Nevada, June-July, 1980. Interim Summ. Rep. to
HDR Sci., Contr. No. HDR/RPA15.
05 Deacon, J.E., C. Hubbs, and B.J. Zahuranec. 1964. Some effects of
introduced fishes on the native fish fauna of southern Nevada.
Copeia 1964:384-388.
06 Deacon, J.E. and J.E. Williams. 1984. Annotated list of the
fishes of Nevada. Proc. Biol. Soc. Wash. 97(1):103-118.
07 Greger, P. 1982. Feeding relationships of the fishes of the
Virgin River. M.S. thesis, Univ. of Nev., Las Vegas.
08 Greger, P. and J.E. Deacon. 1982. Food partitioning among fishes
of the Virgin River. M.S. thesis, Univ. of NV., Las Vegas. 38 pp.
09 Hardy, T.B. 1982. Ecological interactions of the introduced and
native fishes in the outflow of Ash Springs, Lincoln Co., Nevada.
M.S. thesis, Univ. of NV., Las Vegas. 79 pp.
10 Hardy, T.B., C.G. Prewitt, and K.A. Voos. 1983. Application of a
physical habitat usability model to the fish community in a spring
fed desert stream. Pp. 391-397. In: Lavenroth, W.K., G.V.
Skogerboe, and M. Flug. Analysis of Ecological Systems:
State-of-the-Art in Ecological Modeling. Dev. in Modeling 5.
Elsevier Sci. Publ. Co.
11 Hubbs, C., and J.E. Deacon. 1964. Additional introductions of
tropical fishes into southern Nevada. S.W. Nat. 9(4):249-251.
12 La Rivers, I. 1962. Fishes and Fisheries of Nevada. Nev. Fish
and Game Comm., Carson City. 782 pp.
13 Minckley, W.L. 1973. Fishes of Arizona. AZ Game and Fish Dept.
293 pp.
14 Schuman, P.B., E.L. Stuenkel, and J.E. Deacon. Thermal tolerance
and preference of fishes of the Virgin River system (Utah, Arizona,
Nevada). Univ. Nev., Las Vegas. 22 pp.
15 Schuman, P.B. 1978. Responses to temperature and dissolved
oxygen in the roundtail chub, Gila robusta Baird & Girard. M.S.
thesis, Univ. Nev., Las Vegas.
16 Sigler, W.F. and R.R. Miller. 1963. Fishes of Utah. Utah State
Dept. of Fish and Game, Salt Lake City.
17 Tanner, V.M. 1950. A new species of Gila from Nevada
(Cyprinidae). Great Basin Nat. 109(1-4):31-36.
18 Vanicek, C.D., and R.H. Kramer. 1969. Life history of the
Colorado squawfish, Ptychocheilus lucius, and the Colorado chub,
Gila robusta, in the Green River in Dinosaur National Monument,
1964-1966. Trans. Am. Fish. Soc. 98:193-208.
References - 1 (DRAFT) - References
Species CHUB, ROUNDTAIL, PAHRANAGAT
Species Id ESIS251009
Date 14 MAR 96
19 Hardy, C. 1982. Unpubl. data. M.S. thesis research., Univ. Nev.,
Las Vegas.
20 Parker, Kanim. Unpubl. data. M.S. thesis research., Univ. Nev,
Las Vegas.
***** REFERENCES FOR N-OCCURRENCE NARRATIVE ONLY *****
01 Courtenay, W.R., J.E. Deacon, D.W. Sada, R.C. Allan, and G.L.
Vinyard. 1985. Comparative status of fishes along the course of
the pluvial White River, Nevada. S.W. Nat. [In press.]
02 Deacon, J.E., T.B. Hardy, J. Landye, J. Pollard, W. Taylor, and
P. Greger. 1980. Environmental analysis of four aquatic habitats
in east-central Nevada, June-July, 1980. Interim Summ. Rep. to
HDR Sci., Contr. No. HDR/RPA15.
03 Hardy, T.B. 1982. Ecological interactions of the introduced and
native fishes in the outflow of Ash Springs, Lincoln County,
Nevada. M.S. thesis, Univ. Nev., Las Vegas. 79 pp.
04 Miller, R.R. and C.L. Hubbs. 1960. The spiny-rayed cyprinid
fishes (Plagopterini) of the Colorado River system. Misc. Publ.
Mus. Zool. Univ. Mich. 115:1-34.
05 Tanner, V.M. 1950. A new species of Gila from Nevada
(Cyprinidae). Great Basin Nat. 109(1-4):31-36.
References - 2