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vaquita, Gulf of California harbor porpoise, cochito
("porpoise of the gulf")
The vaquita, like other porpoises, differs from dolphins in several ways. Porpoises have a blunt beak, or rostrum, compared to dolphins' more tapered beaks. Porpoises' teeth are spade-shaped; dolphins' teeth are conical. Porpoises also are characterized by more triangular dorsal fins, rather than the curved dorsal fins of most dolphins. In contrast, the dorsal fin of a vaquita is proportionally much higher than those of other porpoise species. The front-or leading-edge of the vaquita's dorsal fin is slightly convex, and the rear-or trailing-edge is almost straight.In size, Vaquitas are the smallest porpoise and among the smallest cetaceans.A vaquita's color is a complex but subdued pattern of various shades of gray, often appearing olive or tawny brown in adults. Most have a bold, dark eye patch and dark lip patch. Calves are typically darker than adults.
Mature males tend to be smaller than females
The vaquita generally reaches a length of about 144 cm (4.7 ft.). The largest vaquita ever measured was a mature female that was 1.5 m (5 ft.) long. Calves are about 70-78 cm (28-31 in.) at birth
Adults weigh up to 46.5 kg (102.3 lb.); newborn calves weigh more than 7.5 kg (17 lb.)
Most of what scientists know about vaquita is based on dead specimens. The vaquita's diet-based on the stomach contents of one specimen-likely consists of grunt, Gulf croakers, and squid.
To at least 21 years
The vaquita lives only in the shallow waters of the upper Gulf of California, Mexico, where the Colorado River empties into the Gulf. Vaquita rarely venture beyond this small area; they have the most restricted range of any cetacean.
Found in shallow water, close to shore
Little is known about the natural history of this rare porpoise. The silty waters of its home at the mouth of the Colorado River are almost always turbid, making observation difficult. There have been just 65 confirmed sightings of live vaquita ever, and scientists estimate that only a few hundred of these porpoises are alive today.
ECOLOGY AND CONSERVATION
The vaquita is one of the world's most endangered cetaceans. Its tiny, isolated population makes it highly vulnerable to human activities.
Vaquita often are caught in nets set to catch other animals. This "incidental take" is the primary reason for the vaquita's endangered status. Gulf of California fisheries include shrimp trawling and gillnet fisheries for sharks. (A gillnet is a large flat fishing net that entangles fish as it hangs vertically in the water.) Each year, 25-30 vaquita drown in gillnets.
Vaquita survival is closely related to one gillnet fishery in particular: totoaba (Totoaba macdonaldi, a type of fish resembling the white seabass). Like the vaquita, the totoaba lives only in the upper Gulf. Vaquita are easily entangled in the larger holes of the totoaba nets. In 1990, the International Whaling Commission (IWC) determined that the totoaba fishery is responsible for the vaquita's endangered status.
Totoaba is itself an endangered species. For many years, totoaba fishing continued with no controls. Even small-scale totoaba fishing was very difficult to monitor. Mexico banned totoaba fishing in 1975. The U.S. has banned imports of totoaba since 1977. But demand for totoaba as a food fish keeps the illegal fishery profitable.
Laws in both the United States and Mexico protect the vaquita. It was placed on Mexico's endangered species list in 1978. The U.S. added the vaquita to its endangered species list in 1985. A vaquita sanctuary was established in the northern Gulf area. But as long as illegal totoaba fishing continues, vaquitas will continue to drown in gillnets. If people continue to buy totoaba, not only will this fish become extinct, so will the vaquita.
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Leatherwood, Stephen, and Reeves, Randall R.
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Walker's Mammals of the World. Vol. II
. Baltimore: Johns Hopkins University Press, 1991.
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Grizmek's Encyclopedia of Mammals. Vol. IV
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National Audubon Society: Guide to Marine Mammals of the World
. New York: Random House, 2002.