Reviews in Fish Biology and Fisheries 12: 157–165, 2002.
© 2003 Kluwer Academic Publishers. Printed in the Netherlands.
Distribution, habitat and conservation status of desert pupﬁsh
(Cyprinodon macularius) in the Lower Colorado River Basin, Mexico
, Gorgonio Ruiz-Campos
Departamento de Investigaciones Cient´ıﬁcas y Tecnol´ogicas de la Universidad de Sonora, Blvd. Luis Encinas
y Rosales s/n, 83000, Hermosillo, Sonora M´exico (Phone: (662)259-2197; Fax: (662)259-2195; E-mail:
Universidad Aut´onoma de Baja California, Facultad de Ciencias Apartado Postal
1653, Ensenada, Baja California, 22800 M´exico (US mailing address: PMB-064, P.O. Box 189003 Coronado, CA
Received 3 April 2001; accepted 10 October 2002
Abstract page 157
Materials and methods 158
Key words: conservation status, desert pupﬁsh, distribution, habitat, Lower Colorado River, Mexico
In order to better determine the current status of desert pupﬁsh populations (Cyprinodon macularius macularius)
in the Lower Colorado River Basin of Mexico, bimonthly ﬁsh sampling and habitat evaluations were carried out
from September 1996 to August 1997 in six localities of Baja California and Sonora. Desert pupﬁsh were collected
using minnow seines and traps. Four sampling sites are in Sonora, in shallow marginal habitats of the Ciénega
Santa Clara (Hunters’ Camp, Outlet of the Welton-Mohawk channel, El Doctor and Flor del Desierto) and two are
in Baja California (Cerro Prieto and streams south of Cerro Prieto). The most abundant ﬁsh species sampled was
native desert pupﬁsh (C. macularius, 59%) followed by sailﬁn molly (Poecilia latipinna, 19%), redbelly tilapia
(Tilapia cf. zilli, 10%) and western mosquito ﬁsh (Gambusia afﬁnis, 7%). Signiﬁcant temporal ﬂuctuations in
distribution and abundance of desert pupﬁsh populations, as previously reported for these populations, was again
documented. The main anthropogenic factors affecting distribution and abundance of desert pupﬁsh populations in
the Mexican portion of the Lower Colorado River Basin are progressive alteration of aquatic and riparian habitats,
as well as presence of exotic ﬁshes that have caused the displacement or elimination of native ﬁsh populations.
Both habitat and presence of the desert pupﬁsh populations in the study area are controlled by the periodicity,
quality and volume of discharges into the Mexican portion of the basin from the United States.
The desert pupﬁsh (Cyprinodon macularius macu-
larius) is a small cyprinodontid once widely distrib-
uted and abundant in the Lower Colorado River basin
of United States of America (USA) and Mexico, as
well as the Sonoyta River and Gila River systems of
northwestern Mexico and southern Arizona (Miller,