Mammals

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.

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.

In early 2007 the population was estimated to be around 150 individuals.

Decreasing.

Classified as Critically Endangered (CR A4d;C2a(ii)) on the 2010 IUCN Red List of Threatened Species.

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.

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.

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.

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.

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.