Research published in the academic journal Mammal Review has uncovered the missing link in the depleting population of the vaquita. With a body less than 1.5 m long, the vaquita is the smallest living cetacean (the order Cetacea consists of whales, dolphins and porpoises). It also has one of the smallest ranges (c. 2235 km2) and one of the smallest populations (< 600 individuals based on a 1997 survey). This little porpoise is one of the two most critically endangered small cetaceans in the world, suggesting that its chances of survival are small, just like its population size and area of distribution. So, what actions have been and are being taken to prevent the vaquitas extinction and promote its recovery" In a recent paper published in Mammal Review, the authors from Mexico and Canada reviewed the scientific issues, described previous and ongoing conservation efforts, and identified remaining obstacles, established priorities, and provided recommendations.
The vaquita is endemic to the north-western corner of the Gulf of California (north of 3045'N and mainly west of 11420'W), an area rich and diverse in marine mammals. It is somewhat surprising that the porpoises are limited to such a small area when there are no obvious physical barriers to prevent them from moving into the rest of the Gulf. However, there is no evidence that the vaquitas overall range has changed in historic times. Acoustic surveys suggest that vaquitas are not only limited to the north-western Gulf all the year-round, but also that their current distribution is more restricted than previously thought confined to a small area off the eastern coast of the Baja California Peninsula.
What is driving the vaquita towards extinction" It is not, as is so often the case, degradation of its habitat. A risk factor analysis discounted pollution or the drastic reduction of freshwater flow from the Colorado River as primary culprits. It is also not a genetic problem. Genetic analyses
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Contact: Davina Quarterman
davina.quarterman@oxon.blackwellpublishing.com
Blackwell Publishing Ltd.
8-Dec-2006