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Vaquita Porpoise

 

Vaquita Porpoise

Vaquita (Phocoena sinus)
Distribution and Habitat
Vaquitas have the most restricted range of any marine cetacean; they appear to live only in the northern end of the Gulf of California. Most sightings of vaquita are in shallow (<40 m) water and within 25 km from the shore.

Vaquita distribution mapNatural History 
Very little is known about the natural history of vaquita, and what is known is based on data collected from less than 50 individual animals. Vaquita appear to be the shortest porpoise, growing to a maximum length of approximately 149 m. Female vaquita appear to be larger than males, and reach sexual maturity when they achieve a length of 1.35 m or so. The smallest measured adult male vaquita was 1.28 m in length. It is believed that females produce one calf annually, usually in late March or early April. Vaquita feed primarily on teleost fishes that are commonly found in the demersal and benthic zones of the shallow waters of the upper Gulf of California. They also appear to consume squids commonly found in that area.

Status and Protection 
Very little is known of the abundance of vaquita. The latest abundance survey, jointly conducted in 1997 by the National Fisheries Institute of Mexico and the US National Marine Fisheries Service produced an estimate of 567 animals, with a 95% confidence interval of between 177 and 1073 individuals. Vaquita are currently listed in the IUCN Red List of Threatened Species as Critically Endangered.

Threats to the Species 
The greatest threat to the remaining vaquita is incidental mortality in fishing gear. Vaquita are known to die in gillnets set legally for sharks, rays, mackerels and chano. They are also known to die frequently in illegal and occasionally permitted gillnet sets for an endangered fish called totoaba. Vaquita are also known to die in commercial shrimp trawls. Because vaquita numbers are so low, any significant increases in annual mortality, whether it be through human intereaction or through rapid environmental perturbation, pose a serious threat to this species

Sources
Vidal, O. et al. 1999. Vaquita. In S.H. Ridgeway & R. Harrison [eds.], Handbook of Marine Mammals, Volume 6: The Second Book of Dolphins and Porpoises. Academic Press. San Diego.

Jefferson, T.A. et al. 1993. Marine Mammals of the World. FAO Species Identification Guide. United Nations Environment Programme. Rome.

Page last modified: 02/12/2013 19:53:25@phocoena.org