Condition status of the endangered desert pupfish, Cyprinodon macularius Baird and Girard, 1853, in the Lower Colorado River Basin (Mexico)

Authors

  • G. Ruiz-Campos,

    Corresponding author
    • Cuerpo Académico Estudios Relativos a la Biodiversidad, Facultad de Ciencias, Universidad Autónoma de Baja California, Ensenada, BC, México
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  • A. Andreu-Soler,

    1. Cuerpo Académico Estudios Relativos a la Biodiversidad, Facultad de Ciencias, Universidad Autónoma de Baja California, Ensenada, BC, México
    2. Fundación Séneca, Programa Séneca 2009, Agencia Regional de Ciencia y Tecnología, Murcia, Spain
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  • A. Varela-Romero

    1. Departamento de Investigaciones Científicas y Tecnológicas de la Universidad de Sonora, Hermosillo, Sonora, México
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Author's address: G. Ruiz-Campos, Cuerpo Académico Estudios Relativos a la Biodiversidad, Facultad de Ciencias, Universidad Autónoma de Baja California, Apdo. Postal 233, Ensenada, Baja California, 22800, México; PMB 064, P.O. Box 189003, Coronado, CA 92178-9003, USA.

E-mail: gruiz@uabc.edu.mx

Summary

The length-weight relationship (LWR) was used to test differences in the fish somatic condition factor among four populations of the endangered desert pupfish, Cyprinodon macularius, from the Lower Colorado River Basin, Mexico. Bimonthly fish sampling and habitat assessments were carried out from September 1996 to August 1997 for four sites in Baja California and Sonora. Slope b of the WLR varied from 3.238 (Cerro Prieto population) to 3.613 (Welton-Mohawk population), showing in all populations a positive allometric growth. Male b values were higher than those of females for Cerro Prieto (3.303 vs 3.071), Welton-Mohawk (3.866 vs 3.579), and Flor del Desierto (3.357 vs 3.169) populations. The Cerro Prieto population showed the highest somatic condition (y-intercept, = −11.759). Water depth and salinity were the ecological variables that better accounted for most of the variation in the somatic condition of this pupfish, with a negative and a positive effect, respectively.

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