MITOCHONDRIAL DNA VARIATION IN THE CRITICALLY ENDANGERED VAQUITA PHOCOENA SINUS NORRIS AND MACFARLAND, 19581

Authors

  • Patricia E. Rosel,

    1. Scripps Institution of Oceanography, University of California, San Diego, California 92093, U. S. A.
    2. Department of Zoology, University of New Hampshire, Durham, New Hampshire 03824, U. S. A. E-mail: patricia.rosel@noaa.gov
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      Patricia Rosel, National Ocean Service, 219 Fort Johnson Road, Charleston, SC 29412 USA. email: patricia.rosel@noaa.gov.

  • Lorenzo Rojas-Bracho

    1. Facultad de Ciencias Marinas, Universidad Autonoma de Baja California(UABC)/ Programa Nacional de Mamíferos Marinos, Instituto Nacional de la Pesca (INP), Km 103 Carretera Tijuana-Ensenda, Ensenada 22800, BC Mexico
    2. Southwest Fisheries Science Center, P. O. Box 271, La Jolla, California 92038, U. S. A.
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    This paper is dedicated to Dr. Ken Norris who, among his many other contributions to marine mammal science, was one of the first to recognize the vaquita as a new species.

Abstract

The vaquita, Phocoena sinus, is one of two critically endangered cetacean species, and is listed as an endangered species in both the United States and Mexico. These listings result from a small population size, estimated to be 224 animals, and a rapid decline in abundance (18% per annum) thought to be caused by human activities. To characterize the genetic composition of the vaquita, we have sequenced a portion of the mitochondrial DNA control region from 43 individuals collected between 1985 and 1993. All animals had identical sequences. While low genetic variability has been reported for cetacean species, this complete lack of polymorphism in the control region is unique. This result is concordant with the hypothesis that the evolutionary history of the species includes a bottleneck or founder event, possibly at species inception, followed by a small long-term effective population size. We recommend parallel studies of nuclear variability, which could provide understanding of the basic biology of the vaquita for use in conservation efforts.

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