7950

• UCREFRP Catalog Number: 7950
• Author: Williams, J. E. and G. R. Wilde
• Title: Taxonomic Status And Morphology Of Isolated Populations Of The White River Springfish,
• USFW Year: 1981
• Copyright Material: YES

TABLE 1. Temperature and minimum dissolved oxygen values of the spring source in waters
containing Crenichthys baileyi. Data from Hubbs and Hettler (1964) and personal observation.

SPRING

TEMPERATURE (oC)

OXYGEN (ppm)

PRESTON BIG
MORMON
HOT CREEK
MOON RIVER
HIKO
CRYSTAL
ASH HEAD POOL
OUTFLOW CREEK
MOAPA HEADWATER SPRINGS
TAYLOR (=HOME)

21.0
37.0
31.3
33.3
26.3
26.0-27.0
35.9
34.0
30.0-31.1
31.0

3.3
0.7
1.6

3.0
1.6-3.0
2.4
2.1-2.6
4.0-5.8
5.7

of various populations of C. baileyi. The need for such an investigation was made urgent
by the recent loss of the Hiko Spring population due to exotic fish introductions.
Largemouth bass (Micropterus salmoides) apparently were introduced into Hiko Spring
in February 1965 (B. L. Wilson, pers. comm.). Shortfin molIies (Poecilia mexicana) and
mosquito fish (Gambusia affinis) were introduced into Hiko in January or February
1965. Shortfin mollies, mosquitofish, and largemouth bass increased in abundance
through 1965. By February 1966, springfish were rare, and were extinct in June 1967. Part
of the Crenichthys decline also is attributable to a parasite, Lernaea, that probably was
introduced along with the exotic fishes. Crenichthys baileyi of Hot Creek Spring were
thought to have been extirpated in the early 1970's when largemouth bass entered the
spring from Dacey Reservoir, where they had been introduced as game fish. Fortunately,
a recently discovered group of the springfish from Hot Creek survived because they were
isolated by den~e emergent vegetation from the main pool area. Exotic species (Poecilia
mexicana, P. reticulata, Gambusia affinis, and Cichlasoma nigrofasciatum) have been
introduced into other springs inhabited by Crenichthys baileyi (Deacon and Bradley
1972, Hubbs and Deacon 1964). Establishment of exotic species has resulted in depressed
activity cycles and reduced population numbers of C. baileyi in these springs (Deacon
and Wilson 1967, Deacon et aI. 1964). Exotic species also have been indicated as sources
of Lernaea (Copepoda) and Contracaecum (Nematoda) that parasitize Crenichthys
baileyi in Moapa River headwater springs (Wilson et aI. 1966). The current status of each
population will be treated in later sections.
The published material relating to this species usually has centered around the fish's
ability to inhabit seemingly hostile environments (Hubbs and Hettler 1964) and their
resulting activity patterns (Deacon and Wilson 1967, Hubbs et aI. 1967). Kopec (1949)
reported on aspects of early life history of C. baileyi. Relatively little attention has been
afforded the taxonomy of this species despit~ the sugge~tion by work on other
cyprinodonts in the southwestern United States that subspecific status might be
warranted for certain populations (Miller 1948). Reider (1971) compared the
morphology of four spring populations of Crenichthys baileyi. However, his failure to
examine specimens from other springs or to separate data by sex ham pered interpretations
of his results and no attempt at describing distinct populations was made.

MATERIALS AND METHODS. During the course of this study we attempted to examine
specimens of Crenichthys baileyi from every locality where they exist or have historically existed.
Specifically, we based our study on series of 30 adult fish from the following springs: Preston Big,

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