Gulf of California Harbor Porpoise / Vaquita (Phocoena sinus) - Office of Protected Resources

Gulf of California Harbor Porpoise / Vaquita / Cochito (Phocoena sinus)

Did You Know?

· The vaquita's scientific species name, sinus, is Latin for "pocket," "recess," or "bay," and refers to the species' limited distribution (Reeves et al. 2002).

· The vaquita is the smallest known cetacean and has the most limited range of any marine cetacean. It also may be considered the world's most endangered cetacean.

· The word vaquita means "little cow" in Spanish.

Status
ESA Endangered - throughout its range
MMPA Depleted - throughout its range

Taxonomy
Kingdom: Animalia
Phylum: Chordata
Class: Mammalia
Order: Cetacea
Family: Phocoenidae
Genus: Phocoena
Species: sinus

Species Description
Vaquitas, also known as the "Gulf of California porpoise" or "Cochito," are elusive and timid members of the porpoise family. They were first described by western scientists in 1958 based on several skulls. This species is probably the smallest known cetacean. These porpoises can reach about 4-5 ft (1.2-1.5 m) in length and weigh 65-120 lbs (30-55 kg). Females are generally slightly larger than males.

Vaquitas have compact, robust bodies and a rounded head with little or no beak. Their triangular "falcate" dorsal fin is proportionately tall and is located in the middle of the back. This species' complex coloration consists of various shades of dull gray that transition from dark on the dorsal side to pale on the ventral side of the body. The lips, chin, and eye ring are black. Individuals get lighter in color as they age, and the face is usually pale.

This species of porpoise is usually found either singly, in pairs, or in small social groups of 7-10 individuals. These shy animals will typically avoid vessels. They are not usually active at the surface and are often difficult to observe visually due to their cryptic behavior.

Vaquitas spend relatively long periods of time underwater to opportunistically feed on a variety of small schooling fish (e.g., croakers and grunts), crustaceans, and cephalopods (e.g., squid and octopus). They have 16-22 pairs of small spade shaped teeth in the upper jaw and 17-20 pairs in the lower jaw that are used to capture prey.

Vaquitas become sexually mature at 3-6 years of age. After a gestation period of about 10-11 months, females typically give birth every other year to a single calf that is about 2.5 ft (0.7-0.8 m) long and weighs about 16.5 lbs (7.5 kg). Calving usually takes place between the months of February and April. These cetaceans have an estimated lifespan of at least 21 years.

Habitat
This species is "endemic" to the shallow, murky coastal waters of the Gulf of California off of the Baja Peninsula in Mexico. They are usually found in waters less than 165 ft (50 m) deep and within 13.5 nautical miles (25 km) of the shore (Shirihai and Jarrett 2006).

Distribution
The vaquita’s distribution is restricted to the upper portion of the northern Gulf of California, mostly within the Colorado River delta. They are commonly seen between San Felipe Bay and Rocas Consag in the western upper portion of their range (Jefferson et al. 2008). The historical distribution of this species may have been much larger, at one time extending south along the Mexican mainland to the Tres Marias Islands and Banderas Bay (Leatherwood et al. 1988).

Population Trends
The vaquita’s population has been in decline since at least the 1940s, and could be declining by as much as 15% each year. The decline began when a commercial fishery using gillnets for the endangered totoaba (a large sea bass) was established by local fisherman in the region in the 1920s (Reeves et al. 2002). The commercial fishery for totoaba ceased in the 1970s, but other fishing still continues. At current rates, the vaquita population may be reduced by more than 80% over the next 10-30 years and is in danger of extinction. The current total population of the vaquita is estimated between 500-600 individuals (Jefferson et al. 2008).

Threats
Vaquitas are incidentally taken as bycatch in local gillnet and trawl fisheries. Commerical fishing is by far the greatest threat to individuals, their habitat, and the species overall survival. It is estimated that at least 30-85 individuals are taken incidentally each year. Other possible threats to this species include environmental pollution, habitat degradation, and inbreeding due to low population numbers (Jefferson et al. 2008).

Conservation Efforts
The International Union for Conservation of Nature and Natural Resources (IUCN's) Red List of Threatened Species considers this species "Critically Endangered." Mexico has taken steps to protect the vaquita by establishing an international committee (CIRVA) as well as a bio-reserve in the upper portion of the Gulf of California in order to conserve and protect the endangered totoaba and vaquita and other threatened wildlife.

Regulatory Overview
This species was listed as "endangered" under the Endangered Species Act in 1985. This species is also protected under the Marine Mammal Protection Act of 1972, as amended.

Key Documents
(All documents are in PDF format.)

Title	Federal Register	Date
ESA Listing Rule	50 FR 1056	01/09/1985

More Information

References:

Reeves, R. R., P. A. Folkens, et al. (2002) Guide to Marine Mammals of the World. New York, Alfred A. Knopf. p. 464-465.
Jefferson, T. A, M. A. Webber, and R. L. Pitman. (2008). Marine Mammals of the World, A Comprehensive Guide to their Identification. Amsterdam, Elsevier. p. 288-289.
Leatherwood, S., R. R. Reeves, et al. (1988). Whales, Dolphins, and Porpoises of the Eastern North Pacific and Adjacent Arctic Waters: A Guide to Their Identification. New York, Dover Publications, Inc. p. 208.
Shirihai, H. and B. Jarrett (2006). Whales, Dolphins and Other Marine Mammals of the World. Princeton, Princeton University Press. p. 254-255.