63.
Vaquita
(Phocoena sinus)
CR
Overview
Mexico's only endemic marine mammal, the vaquita is a slender porpoise with distinctive dark rings around the eyes and mouth. It is the world's smallest and most endangered cetacean, and lives in the warm shallow coastal waters in the northern end of the Gulf of California. The vaquita is the only species of porpoise to live in such warm waters, and can uniquely tolerate large fluctuations in temperature. Although vaquita have never been hunted directly, populations are declining as a result of incidental mortality in fishing gear.A recent alarming study has shown that a mere 150 individuals remain. With current annual mortalities estimated at around 40 vaquitas per year, immediate action is required in order to save this species from extinction.
Urgent Conservation Actions
Eliminate bycatch, habitat protection, public awareness and education programmes, development of alternative fishing gear and sources of income for local fishing communities.
Distribution
Upper Gulf of California, Mexico.
Fact
The vaquita is the only cetacean to show polydactyly (additional digits, in this case additional skeletal digits within the flipper) as a constant bilateral trait
Associated Blog Posts
6th May 12
The vaquita porpoise (Phocoena sinus) is Mexico's only endemic marine mammal. Along with dolphins, porpoises belong to the superfamily Delphinoidea. Now ...  Read

28th Jan 11
This is the first in a series of blogs written by George Tyson, a graduate journalist with a keen interest in conservation. As the conditions of global ...  Read

Media from ARKive
ARKive image - Vaquita calf at the surface
ARKive image - Vaquitas swimming at the surface
ARKive image - Dorsal fin of a vaquita at the surface
ARKive image - Vaquita
ARKive image - Adult vaquita with young in habitat
ARKive image - Vaquita in habitat
ARKive image - Vaquita in habitat
ARKive image - Female vaquita being hauled in by a fisherman as bycatch
ARKive image - Vaquita as bycatch, being hauled in by a fisherman
ARKive image - Dead vaquita, caught in a fishing net as bycatch
ARKive image - Dead vaquita, caught in a fishing net
ARKive image - Adult and young vaquitas
ARKive image - Four dead vaquitas on beach
ARKive image - Dead vaquita on table
ARKive image - Dead young vaquita with children
Evolutionary Distinctiveness
Order: Cetacea
Family: Phocoenidae
Porpoises (Phocoenidae), dolphins (Delphinidae), and the two species of Monodontidae (beluga and narwhal) together constitute the superfamily Delphinoidea. The delphinoids are thought to have originated sometime between 25 and 11 million years ago. Determining the phylogenetic relationships within this superfamily has proven difficult. Porpoises were originally classified in the same family as the dolphins, based on superficial similarities. However, they are now regarded as sufficiently distinct to warrant their own familial ranking, and recent studies indicate that porpoises share a more recent common ancestry with the white whales than either does with the dolphins. There are six living species of porpoise, in three genera: Neophocaena phocaenoides (finless porpoise), Phocoenoides dalli (Dall's porpoise), Phocoena dioptrica (spectacled porpoise), Phocoena phocoena (harbour porpoise), Phocoena spinipinnis (Burmeister's porpoise) and Phocoena sinus (vaquita). Recent molecular data suggest that there is a close relationship between P. spinipinnis and P. sinus.
Description
Size: 
Body length: 120-150 cm
Male: 128-145 cm
Female: 135-150 cm
Weight: approx. 55 kg
The vaquita is the world’s smallest and most endangered marine cetacean. Its skin is dark grey above, fading to pale grey or white below. Vaquitas have distinctive dark rings around the eyes and mouth, and a dark stripe from the chin to the base of the flipper. They are similar in size and shape to the harbour porpoise (Phocoena phocoena), although they are more slender and have relatively larger fins. These features are thought to increase the surface area of the porpoise’s body to facilitate heat dissipation in the warm waters it inhabits. Female vaquitas are slightly larger than males.
Ecology
The species is thought to be primarily solitary. Individuals are generally seen travelling alone or in small groups of 1-3 individuals, although they are sometimes observed swimming in groups as large as ten. Like other porpoises, the vaquita uses sonar as a means of communicating and navigating through its habitat. It feeds primarily on teleost (bony) fish and squid which are found at or near the bottom of the sea. Individuals reach sexual maturity when they reach a length of approximately 1.3 m, between the ages of three and six years. Reproduction is seasonal, with a single young being born in March, after a gestation period of around 10-11 months. The interbirth period is thought to be around two years. The maximum observed age of this species is 21 years.
Habitat
Lives in shallow, murky lagoons along the shoreline where there is strong tidal mixing, convection processes and high food availability. The species is rarely seen in waters deeper than 30 m. The water temperatures here fluctuate annually, ranging from 14°C in January to as high as 30°C in August. The vaquita is the only species of porpoise to live in such warm waters, and is unique in its ability to tolerate these large fluctuations in temperature.
Distribution
This species has the most limited distribution of any marine cetacean. It is found only in shallow waters at the northern end 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 localised, with the highest densities offshore of San Felipe and Rocas Consag, and offshore of El Golfo de Santa Clara.
Population Estimate
In early 2007 the population was estimated to be around 150 individuals.
Population Trend
Decreasing.
Status
Classified as Critically Endangered (CR A4d;C2a(ii)) on the 2010 IUCN Red List of Threatened Species.
Threats
Vaquita are vulnerable because they are rare and have such a limited distribution. Although they have never been hunted directly, the population continues to decline, primarily as a result of incidental mortality in fishing gear. Vaquita frequently die in illegal gillnets set for the endangered totoaba fish (Totoaba macdonaldi), as well as in gillnets set for sharks, rays, mackerels, chano and shrimp, and occasionally in commercial shrimp trawls. When the animals become entangled in fishing nets they cannot surface to breathe, and therefore drown. It is estimated that between 39 and 84 individuals die in this way each year. Juveniles are particularly susceptible to entanglement in nets, and researchers are concerned that this will lead to a decrease in the number of reproductive adults in the population, leading to further and more rapid declines. The damming of the Colorado River in the United States has led to a decrease in freshwater input into the upper Gulf of California. The long-term consequences of this drastic habitat alternation on the vaquita are also matters of concern.
Conservation Underway
Much of the vaquita’s habitat is located in the Upper Gulf of California and Colorado River Delta Biosphere Reserve (est. 1993). All forms of fishing are prohibited in the core area of this reserve, and there are restrictions on gill net fishing in the buffer zone. However, these restrictions are rarely enforced. In 1997 the Mexican government created the International Committee for the Recovery of the Vaquita (CIRVA), which is composed of government representatives and scientists from Mexico, the United States, Canada and the United Kingdom. CIRVA has identified fishery bycatch as the greatest and most immediate threat to the species, and has produced a long-term vaquita recovery plan based on available scientific information. In 2000, WWF, Conservation International (CI) and various other NGOs established a working group to implement recommendations made by CIRVA and investigate sustainable economic alternatives for local fishermen and communities who depend on the Gulf’s resources for their own survival. However, it has not yet proved possible to implement the conservation recommendations regarding removal of harmful fishing nets from across the entirety of the species' range.
Conservation Proposed
Almost half of all vaquita sightings occur outside the Biosphere Reserve’s southern boundary. This means that a ban on gill net fishing within the reserve is unlikely to be sufficient to ensure the survival of the species. The IUCN/SSC Cetacean Specialist Group and CIRVA therefore recommend that the southern boundary of the reserve be extended to include the entire range of the species, and that fishing methods that result in bycatch of vaquitas be eliminated from this area. However, while banning gillnets and trawlers throughout the entire range of the vaquita is the single measure most likely to prevent the species' extinction, this move is likely to have profound political, cultural, social and economic implications in local communities. Public awareness and education programmes are therefore an essential component of any future conservation programme, as it is only with the cooperation of local communities that this species can be saved. Alternative sources of income should be developed for the local fishing communities in addition to the development of alternative fishing gear that won't harm the vaquita. Further investigation into abundance and seasonal movements of vaquitas would also be useful so that more effective protection measures can be implemented.
Associated EDGE Community members

Jay is a world leader in cetacean and pinniped conservation

Links
Vaquita Marina WWF-Mexico's vaquita website features detailed information on the vaquita, images, and the latest conservation news. It also includes a list of all organisations and individuals involved in vaquita conservation.

Whale and Dolphin Conservation Society (WDCS)

Vaquita.org is a network of world-class marine mammal scientists, fisheries economists, project managament specialists, professional fundraisers and communication experts. The organization develops, implements and funds community participation-based conservation initiatives that aim to reduce vaquita by-catch to zero, improve the lives of local fishing communities and encourage the equitable and sustainable use of fishery resources within the northern Gulf of California.
References
Cetacean Specialist Group. 1996. Phocoena sinus. In: IUCN 2006. 2006 IUCN Red List of Threatened Species. Downloaded on 25 July 2006.


Convention on Migratory Species (CMS): Phocoena sinus, Vaquita

D'Agrosa, C., Lennert-Cody, C.E. and Vidal, O. 2000. Vaquita bycatch in Mexico's artisanal gillnet fisheries: driving a small population to extinction. Conservation Biology 14: 1110–1119.

Jaramillo-Legorreta, A., Rojas-Bracho, L., Brownell, RL Jnr., Read, A.J., Reeves, R.R., Ralls, K. and Taylor, B.L. 2007. Saving the Vaquita: Immediate Action, Not more Data. Conservation Biology (In Press).

May-Collado, L. and Agnarsson, I. 2006. Cytochrome b and Bayesian inference of whale phylogeny. Molecular Phylogenetics and Evolution. In press.

Nowak, R. M. 1999. Walker’s Mammals of the World. Sixth edition. The Johns Hopkins University Press. Baltimore and London.

Reeves, R. R., Smith, B. D., Crespo, E. A. and Notarbartolo di Sciara, G. 2003. Dolphins, Whales and Porpoises: 2002-2010 Conservation Action Plan for the World’s Cetaceans. IUCN: Gland, Switzerland.
Rojas-Bracho, L., Reeves, R.R., Jaramillo-Legorreta, A. & Taylor, B.L. 2008. Phocoena sinus. In: IUCN 2010. IUCN Red List of Threatened Species. Version 2010.4.www.iucnredlist.org<. Downloaded on 14 November 2010.

Rojas-Bracho, L., Reeves, R.R., Jaramillo-Legorreta, A. & Taylor, B.L. 2008. Phocoena sinus. In: IUCN 2009. IUCN Red List of Threatened Species. Version 2009.2. <www.iucnredlist.org>. Downloaded on 16 February 2010.

Rojas-Bracho, L. and Taylor, B. L. 1999. Risk factors affecting the vaquita (Phocoena sinus). Marine Mammal Science 15(4): 974-989.

Vaquita Marina

Waddell, V. G., Milinkovitch, M. C., Be´ rube´, M. and Stanhope, M. J. 2000. Molecular Phylogenetic Examination of the Delphinoidea Trichotomy: Congruent evidence from three nuclear loci indicates that porpoises (Phocoenidae) share a more recent common ancestry with white whales (Monodontidae) than they do with true dolphins (Delphinidae). Molecular Phylogenetics and Evolution 15(2): 314-318.

Distribution map based on data provided by the IUCN Global Mammal Assessment.

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