(Phocoena sinus)

Morphology

The Vaquita is very similar in appearance to the Harbor Porpoise. In fact, very little is known about the external differences between the two species, beyond the fact that the Vaquita is often much darker in color. The body length of the Vaquita ranges from 1.2 to 1.5 meters. It is the smallest of the porpoises, and perhaps the smallest of all cetaceans.

Color

Like the Harbor Porpoise, this speices is medium to dark grey in color on the dorsal side. The ventral portion of the body is light grey to white in color. There is a dark strip extending from the chin to the flippers. There is also dark coloring around the mouth and dark patches around the eyes.

Fins

The dorsal fin is located higher up on the body than other members of the family Phocoenidae. It has a convex leading edge that is sometimes covered in tubercles. The placement and style of the dorsal fin in this species resembles the fin arrangement of most sharks. The flippers, which are small and broad, are located in the white portion of the body. The fluke, which remains under water when diving, is small and possesses a notch and pointed tips.

Behavior

This species is the most secretive of all porpoises. Vaquitas are never observed in pairs or groups. In fact, they are rarely ever seen in the wild at all. Bow-riding has never been recorded by a Vaquita. This porpoise seems to intentionally avoid boats.

Swimming Style

This porpoise swims leisurely, rising slowly and disturbing very little water as it breaks the surface to breath. Breaching has never been observed by this species.

Life History

Very little is known about the reproductive biology of this species. Juveniles possess white spots on the leading edge of the dorsal fin.

Diet

The primary diet of this species is believed to be fishes and squid. Specifically, remains of grunt and Gulf croakers have been found in the stomach of one individual.

Distribution/Population

Vaquitas are found only in the upper portion of the Gulf of California. There is believed to be a seasonal north to south migration of this species within their limited range. Population numbers for this porpoise are unknown, though they are believed to be dangerously low, perhaps between 100-500 individuals. Vaquitas are considered by many to be the most endangered of all the small cetaceans.

Harms

This species is threatened by incidental catch in gill nets, like other porpoises, but their greatest threat appears to be loss or modification of habitat. Damning of the Colorado River is believed to have reduced the productivity of the Gulf of California. Similarly, the Gulf is contaminated with pesticides. Both of these factors are thought to have negative impacts on the survival of this speces. In fact, the state of the Vaquita is believed to be so critical, it is listed as endangered by the IUCN-World Conservation Union. Also, this species is listed as endangered in both the United States and Mexico.