7133

• UCREFRP Catalog Number: 7133
• Author: Jensen, B. L.
• Title: Role of Fish Culture in Endangered Fishes Recovery
• USFW Year: 1986
• USFW - Doc Type: Transactions of the Bonneville Ch. of the AFS
• Copyright Material: YES

Dexter NFH is located in the Pecos River Valley of southeastern
New Mexico. Elevation is 3,500 ft, average annual rainfall about
12 inches, and the growing season 180-200 days. Water is supplied
by three shallow wells, is slightly alkaline (pH 7.2 to 7.5), and
temperature is a constant 64° F. Total hardness averages 2,100
ppm and total dissolved solids approximately 3,500 ppm. Culture
facilities at Dexter consist of a holding house (with sixteen 350-
gal tanks, a hatching battery, and laboratory) and 48 earthen
ponds. Ponds vary from 0.1 to 1.8 acres, comprising a total of
20.8 acres. Wastewater is impounded on the station and thus is
isolated from all other surface waters in the area (Jensen in
Rinne et al., in press).
PROGRAM OBJECTIVES
The program at Dexter NFH was implemented to assist in recovering
imperiled southwestern fishes, most of them federally listed. The
following objectives were selected to plan and carry out the
program: (1) maintain a viable, protected gene pool of imperiled
desert fishes, (2) develop techniques for culturing them, (3)
study their biological requirements, (4) provide live and
preserved fish to cooperating agencies and institutions, (5)
provide an exchange of expertise and data on their culture and
management, (6) publish findings, and (7) implement a public
information program concerning the plight of, and recovery efforts
for, imperiled fishes of the region (Jensen 1983).
MAINTENANCE OF GENETIC DIVERSITY
An important aspect of holding, culturing and reintroducing
imperiled fishes is maintenance of genetic variation. The problem
regarding the management of any species that is artificially mass-
produced or held in artificial (unnatural) habitats is_the
perpetuation of the "natural" gene pool (Buth and Murphy 1.984).
Does maintenance and production of fish species in artificial
habitats and/or artificial propagation result in a loss of
variability that would change their genetic makeup or impact their
ability to reestablish-self-sustaining "natural" populations once
reintroduced into historic habitats?
This has been and remains a major concern of the Dexter program
and has been answered in part by separate electrophoretic studies
on Dexter held and produced fishes. Tony Echelle (pers. comm.),
Oklahoma State University, compared simultaneously collected wild
and Dexter held Pecos gambusia, and Comanche Springs and Leon
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