Animal Info - Vaquita

(Other Names: Cochito, Gulf of California Harbor Porpoise, Gulf of California Porpoise, Gulf Porpoise, Hafenschweinswal, Marsouin du Golfe de Californie, Vaquito)

Phocoena sinus

Status: Critically Endangered

1. Profile (Picture)
2. Tidbits
3. Status and Trends (IUCN Status, Countries Where Currently Found, Population Estimates, History of Distribution, Threats and Reasons for Decline)
4. Data on Biology and Ecology (Size and Weight, Habitat, Age to Maturity, Gestation Period, Birth Season, Birth Rate, Early Development, Maximum Age, Diet, Behavior, Social Organization, Mortality and Survival)
5. References

Profile

Pictures: Vaquita #1 (5 Kb JPEG) (Cetacea); Vaquita #2 (16 Kb JPEG) (@phocoena.org); Vaquita #3 (56 Kb JPEG) (Swiss Cetacean Soc.)

The vaquita is the smallest living cetacean, weighing up to 55 kg (120 lb). It resembles the common porpoise. The main body color is gray, darker above than below and also around the eyes and mouth. There is a dark stripe from the chin to the base of the flipper. The vaquita lives in shallow lagoons along the shoreline where there is strong tidal mixing and high productivity of the aquatic plant and animal communities.

The vaquita appears to be a non-selective feeder on small bottom-dwelling fish and squid. It swims and feeds in a leisurely manner, but it is elusive and will avoid boats of any kind. High-frequency clicks are used for echolocation. The vaquita occurs singly or in small groups, usually from 1 - 3 individuals but as many as 8 - 10.

The vaquita declined in conjunction with the intensification and modernization of commercial fisheries, starting in the 1940's. Currently, the fisheries aimed at a variety of species are intensive in the upper Gulf of California, and the incidental trapping and drowning of vaquitas, particularly in gill and trawl nets, is their principal threat. In addition, the vaquita's habitat has been drastically altered by damming of the Colorado River in the USA. Long-term changes due to the reduced freshwater input are matters of concern. However, the immediate priority is to eliminate the bycatch of vaquitas in fishing gear.

Tidbits

*** The vaquita is one of the world's rarest mammals, and it has the most limited distribution of any cetacean.

*** The vaquita was first documented by science in 1958.

*** The vaquita is the smallest porpoise in the world.

Status and Trends

IUCN Status:

1970's - 1980's: Vulnerable
1994: Endangered
1996 - 2004: Critically Endangered (Criteria: C2b) (IUCN 2004)

Countries Where the Vaquita Is Currently Found:

2004: Occurs in Mexico. (IUCN 2004)

Population Estimates:

[Note: Figures given are for wild populations only.]

WORLD (Mexico)
- 1986-88: 503 (CV = 0.63) (Barlow et al. 1997)
- 1988-89: 885 (CV = 0.50) (Barlow et al. 1997)
- 1991: 572 (CV = 1.43) (Barlow et al. 1997)
- 1993: 224 (CV = 0.39) (Barlow et al. 1997)
- 1997: 567 (95% CI: 177 - 1073) (WWF - Mexico 2002)
- 1999: In the mid-hundreds (Reeves et al. 2003)
- 2002: About 500 (Focus 2002a)
- 2004: Less than 600 (Oryx 2004d)

History of Distribution:

The vaquita may have formerly occurred in Mexico throughout the Gulf of California. It was considered abundant in the early 20th century. As of the early 1980's, the only recent records of its occurrence were from the northern part of the Gulf of California. Currently it has the most limited distribution of any marine cetacean. It is restricted to the northwestern corner of the Gulf of California, from Puertecitos, Baja California Norte, north and east to Puerto Peflasco, Sonora. It is most commonly found around the Colorado River delta. The distribution in the upper Gulf of California appears to be highly localized, with the highest densities offshore of San Felipe and Rocas Consag, and offshore of El Golfo de Santa Clara. (Culik 2003)

Distribution Map #1 (26 Kb GIF) (@phocoena.org)
Distribution Map #2S (13 Kb JPEG) (WCMC/CMS) (smaller map )
Distribution Map #2L (33 Kb JPEG) (WCMC/CMS) (larger map)

Threats and Reasons for Decline:

Data on Biology and Ecology

Size and Weight:

Length: Females - up to 1.5 m (5'); males - up to 1.4 m (4.6'). Weight: up to 55 kg (120 lb).

Habitat:

The vaquita lives in shallow lagoons along the shoreline. It is usually found in waters 10 - 28 m (33 - 92') deep within 25 km (16 mi) from shore, although it can survive in lagoons so shallow that its back protrudes above the water. Other characteristics of its habitat are strong tidal mixing and high productivity of the aquatic plant and animal communities. (Carwardine 1995, Culik 2003)

It occurs in the Sea of Cortez Global 200 Ecoregion. (Olson & Dinerstein 1998, Olson & Dinerstein 1999)

Age to Maturity:

Females may become sexually mature at a length of approximately 1.3 m (4.4').

Gestation Period:

The gestation period is probably 10 - 11 months (Culik 2003).

Birth Season:

Births are thought to occur generally around late March or early April.

Birth Rate:

A female probably produces 1 calf annually.

Early Development:

A vaquita calf is weaned after several months (Burnie & Wilson 2001).

Maximum Age:

The maximum observed age is 21 years (Culik 2003).

Diet:

All of the 17 fish species found in vaquita stomachs can be classified as demersal and/or benthic species inhabiting relatively shallow water in the upper Gulf of California. It appears that the vaquita is a rather non-selective feeder on small fish and squid. Squid remains were also found in several stomach samples. (Culik 2003)

Behavior:

The vaquita appears to swim and feed in a leisurely manner, but it is elusive and will avoid boats of any kind. It rises to breathe with a slow, forward-rolling movement that barely disturbs the surface of the water, and then disappears quickly, often for a long time. (Culik 2003) It uses high-frequency clicks for echolocation. (Burnie & Wilson 2001)

Social Organization:

The vaquita occurs singly or in small groups. One report indicated that in 58 sightings, 91 % comprised from one to three individuals, with a mean group size of 1.9 and a range of 1 - 7. Loose aggregations of vaquitas, in which they were dispersed as single individuals or as small subgroups (from two to four members, greatest number eight to ten) throughout several hundred sq m (several thousand sq ft) were also reported. (Culik 2003)

Mortality and Survival:

The total estimated incidental mortality caused by one fishing fleet in the Gulf of California was 39 vaquitas per year (95% CI = 14 - 93). (D’Agrosa et al. 2000)

References

Barlow et al. 1997, Burnie & Wilson 2001, Burton & Pearson 1987, Carwardine 1995, Cetacea, Culik 2003, D’Agrosa et al. 2000, Focus 2002a, IMMA 1999, IUCN 1994, IUCN 1996, IUCN 2000, IUCN 2003a, IUCN 2004, Klinowska 1991, Nowak & Paradiso 1983, Olson & Dinerstein 1998, Olson & Dinerstein 1999, Oryx 1988i, Oryx 2004d, @phocoena.org, Reeves et al. 2003, Swiss Cetacean Soc., Vidal 1993, WCMC/CMS, WWF - Mexico 2002

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Last modified: November 2, 2005;