8189

• UCREFRP Catalog Number: 8189
• Author: Johnson, J. E. and J. N. Rinne
• Title: The Endangered Species Act and Southwest Fishes
• USFW Year: 1982
• USFW - Doc Type: Fisheries
• Copyright Material: NO

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THE ENDANGERED SPECIES ACT
AND SOUTHWEST FISHES 7l3S
James E. Johnson and John N. Rinne
he native fish fauna of the American Southwest' is char-
Tacterized by endemism and unique adaptations to some of
the harshest aquatic environments in the world (USDI 1978;
Naiman and Soltz 1981). From the large pike-like Colorado
squawfish (Ptychocheilus Lucius) and bizarre humpback chub
(Gila cypha) to the minuscule Comanche Springs pupfish
(Cyprinodon efegans) and the colorful Arizona trout (Salmo
apache), native fishes of this region display a remarkable assem-
blage of physiological, morphological, and behavioral traits (see
covers for photos). But despite these unique adaptations, and
perhaps even more noteworthy, most of the native Southwest-
ern fishes are now facing the real and imminent threat of extinc-
tion.
More than three decades ago Miller (1946) made a plea to
study fishes in Western rivers, and later (Miller 1961) docu-
mented their decline. As he projected, native Southwestem fishes
are disappearing. Twenty-seven of the 44 (61%) U.S. fish spe-
ties listed under the federal Endangered Species Act of 1973
are endemic to the Southwest. Deacon et al. (1979) listed 251
taxa of fishes in North America as likely candidates for federal
listing under the 1973 Act; 199 of those are native to the United
States and 94 (47%) are native to the Southwest. These figures
become even more significant when one considers the lack of
diversity of the Southwestem fish fauna. Twenty-two of the 27
(81%) native Arizona fish species are listed by state or federal
agencies as nearing extinction, and 31 of 73 (42%) native New
Mexico species are similarly designated. In addition, 19% of
Arizona's native fish species have been extirpated and 16% of
New Mexico's fishes have succumbed to the same fate. Pfister
(1981) noted that 20 taxa of fish are native to the desert regions
'This paper uses the approximate U.S. boundaries of Brown and Lowe
(1980) to define the American Southwest, and includes Arizona. New
Mexico, west Texas. and southern portions of California. Nevada. Utah,
and Colorado.
of California; seven of those are extinct and six others are endan-
gered. These losses demonstrate a continuing and progressive
depletion of the native fishes of this region and s}rggest the entire
assemblage of Southwestem fishes could be considered an
endangered faunal group.
The present dilemma of Southwestem fishes results principally
from the ubiquitous loss of aquatic habitats. This in turn has led
to reductions in .geographic ranges and local extirpations of
species, and is directly attributable to the ever-increasing activi-
ties of man (Miller 1961). Purposeful changes in the major rivers
,r.r.: , .;¢a . ~~h ^1g~ ..f.t,,,1?Fc!a, ~Ytio^ Act
,,....:5 Te j:~^ .. u c p:..... a w.. y gc ~ _ _ _ _
of 1902 and began in 1911 with completion of the Roosevelt
Dam on the Salt River in central Arizona. Control of the mighty
Colorado River began with closare of Boulder Dam in 1932;
today, the Colorado River is perhaps the mast regulated river in
the world, its total flow now being spread over the deserts of the
Southwest The natural annual cycle of flooding and drought
are now totally buffered, and the present flows are dictated by,
and obligated to, power and irrigational demands. High dams
THE AUTHORS: James E. Johnson began working . a
^:'~~th desert fishes in 1965. He obtained his Ph.D. from
`~ Arizona State University in 1969. He taught ichthyology
at Arizona State University in ~~1970, taught fisheries at the
'. University of Massachusefts from 1970 to 1974,'was a '
fisheries biologist for the Bureaii`of.Land Management in
~' Colorado in 1975, end since 1976 has worked in the
Office of Endangered Species, U.S: Fish and Wildlife Ser-
~~~: vice, in Albuquerque.; A merr-ber of AFS since 1966, he
"~, is a certified Fisheries Saentist, past president of the Ari-
zona-New Mexico Chapter and member of the'AFS and =~
Western Division AFS Endangered Species Committees.
;~ Hgis presently chairman of the Desert Fishes Coundl. Hts
address at USFWS, Office of Endangered Speaes, is P.O.
'' $oz 1306, Albuquerque, N.M 87103. John N. Rinne
3 obtatned both his M.S. (1969) and Ph.D.,(1973) from the -
~~ pepan7rrerit, of Zoology at Arizona State.University. He
has been working with the U.S: Forest Service Range and --
-. _ _
`:~ Forest Experiment Station in Tempe, Arizona; since 1976,
.. where he. is.currently conducting research on habrtats, ,
;:
-- biology, and distribution ~of desert fishes: He has been a ,
member of AFS since 1969 and past president of the
`Arizona-New Mexico Chapter. He is current chairman of
;; _the Western Division's Endangered Spades Committee. ,
His address with the Forest Service is Rocky Mountain
Forest Range and Experiment Station, Forest Hydrology
Lab, Arizona State University, Tempe, Arizona 85281.
Fisheries, Vol. 7, No. 3
John N. Rinne
James E. Johnson