7952 ‎(2)‎

• UCREFRP Catalog Number: 7952
• Author: Miller, R. R. and B. Chernoff.
• Title: Status of Populations of the Endangered Chihuahua Chub,
• USFW Year: 1979.
• Copyright Material: YES

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Status of Populations of the Endangered Chihuahua Chub, Gila ni
in New Mexico and Mexico ,._,
Robert Rush Miller and Barry Chernoff
Museum of Zoology, The University of Michigan
Ann Arbor, Michigan 48109
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Abstract--The current (1979) population status and habitat requirements of
Gila nigrescens were determined throughout the range in four separate river
systems and one isolated basin in New Mexico and Chihuahua, Mexico. The species
occurred at eight of 16 localities where it was formerly common, but was
abundant at only three stations. It is thus regarded to be an endangered
species. Reasons for its decline are modification of the habitat due to
depletion of ground water, channelization, water diversion, and pollution.
~Exotic,:predatory fish species may also contribute to its reduction. Adult
chubs require pools, shade, and undercut banks or protective cover for successful
spawning; a constant flow of water may not be necessary for survival, A
resolution has been sent to the U.S. Department of t11e Interior requesting
that G. nigrescens~be listed as an endangered species and that stock from the
Mimbres River, New Mexico (now being cultured), be reintroduced into that river
when a suitable refuge becomes available.
Abstracto--E1 estado actual (1979) y los requimientos ecologicos del
_ cyprinido, Gila nigrescens,_fueron determinados en las cuencas cerradas del
Rio Mimbres en Nue ov Mexico, E.E.U.U., y en la Laguna de Bustillos, y 1os v
Rios Casas Grandes, Santa Maria, y del Carmen en Chihuahua, Mexico. Encontramos
poblaciones de esta especie en oclio de los dieciseis localidados estudia.dos,
siendo abundante en solo tres. Es por esto que 1a consideramos una. especie
amenazada. Las poblaciones llegan a ser es cases a causa de modif.icaciones
ambientales, tales como el agotamiento de las aguas subterraneas y la canalizacion,.
diversion y contaminacion de las aguas superf.iciales. I.'ara reproducirse,
los adultos requieren charcos (1 m o mas.de profundidad), sombra y lugares
de abrigo. Parece ser que no requieren agua corriente Para sobrevivir.
Hemos enviado una resolution al Departamento del Interior, E.E.U.U., indicandoles
que consideren Gila nigrescens: como especie amenazada. Tambien, recomendamos
que reintroduzcan Gila nigrescens en e1 .Rio Mimbres, Nuevo Mexico,despues de
la restuaracion de la habitat natural.
Until recently, the representative of the genus Gila inhabiting the Rio
Grande basin has been generally identified as Gila nigrescens (Girard), the
Rio Grande chub (Bailey et al., 1970:20). In an unpublished study by Teruya
Uyeno and R.R. Miller in 1960 that is now being updated and augmented, it was
determined that this chub should be called Gila Pandora (Cope). That concl-usion
received advance documentation by Miller (1961) and by Miller and Hubbs (1962),
who described some of the characters by which G. Pandora and G. nigrescens
differ. - -'
The fish we now call the Chihuahua chub was first described as Gila
cc:Col. Roth, COE
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