Introduction

Cetaceans are the most diverse group of mammals inhabiting the world’s seas and oceans; it includes whales, porpoises and dolphins. With a cosmopolitan distribution, the group includes species that periodically visit or are permanent residents of Mexico’s seas. Out of 86 cetacean species known worldwide (Reeves et al., 2003), 39 have been recorded in national waters, representing over 45 percent of all known species (Ramírez et al., 2008). As for their geographical distribution, the Gulf of California is the part of the country that is richest in cetaceans, with 35 species, followed by the Gulf of Mexico with 28 (Lara-Lara et al., 2008) and the North Pacific with 26 (Semarnat, 2003).

Cetaceans face multiple threats in Mexico and around the world, and 36% of the species are at risk of  extinction (PNUMA, 2009). In addition to hunting, other major threats include incidental capture through inadequate fishing practices, water pollution, collisions with vessels, and tourism activities (WWF, 2001; Medrano and Urbán, 2002, Urbán et al., 2005; Robles et al., 2007).

Mexico is one of the countries most interested in the conservation of cetaceans and other marine mammals. The decree by the Mexican Government establishing Mexican territorial waters as a whale refuge area in May 2002, the creation of protected natural areas for the protection of whales and the enacting of dedicated regulations are clear examples of government actions aimed at the protection of cetaceans. However, much remains to be done to ensure the permanence of cetaceans in national waters.

Due to the lack of data about most of the species that inhabit or visit Mexican waters, this section focuses only on three species: the gray (Eschrictius robustus) and humpback (Megaptera novaeangliae) whales, both migratory species that breed in the temperate waters of the Northern Mexican Pacific during the winter, and the vaquita (Phocoena sinus), a narrowly endemic species inhabiting the Upper Gulf of California and the Colorado River delta.

References

Lara-Lara, J.R. et al. Los ecosistemas costeros, insulares y epicontinentales.  En: Capital natural de México, vol.1: Conocimiento actual de la biodiversidad. Conabio, México. 2008.  

Medrano, G. L. y R. J. Urbán. La ballena jorobada (Megaptera novaeangliae) en la Norma Oficial Mexicana 059-ECOL-2001. Informe final del Proyecto W024. Conabio. México. 2002.

PNUMA. Anuario 2009. Avances y progresos científicos en nuestro cambiante ambiente. 2009.

Ramírez P.J., J. Arroyo y N. González. Mamíferos, en S. Ocegueda y J. Llorente-Bousquets (Coords.). Catálogo taxonómico de especies de México. En: Capital natural de México, vol. I: Conocimiento actual de la biodiversidad. CONABIO. México. 2008. CD1.

Reeves, R.R., Smith, B.D., Crespo, E.A. and di Sciara, G. N. (compiladores). Dolphins, Whales and Porpoises: 2002-2010 Conservation Action Plan for the World´s Cetaceans. IUCN/SSC Cetacean Specialist Group. IUCN, Gland, Switzerland and Cambridge, UK. 2003.

Robles R.; A. Berraho; J.A. Camiñas; M. Najih y A. Alcántara. Conservación y desarrollo sostenible del mar Alborán: Elementos estratégicos para su futura gestión. Centro de Cooperación para el Mediterráneo – UICN. 2007.

Semarnat. Informe de la situación del medio ambiente en México. Compendio de Estadísticas Ambientales, 2002. México. 2003.

Urbán R. J., L. Rojas-Bracho, M. Guerrero-Ruíz, A. Jaramillo-Legorreta y L.T. Findley. Cetacean Diversity and Conservation in the Gulf of California. En: J.L.E. Cartron y G. Ceballos (Eds.). Biodiversity, ecosystems, and conservation in Northern Mexico. Oxford University Press, Oxford, U.K. 276-297 pp. 2005.

WWF. New Threats Endanger Great Whales. 2001. Disponible en:
http://www.actionbioscience.org/esp/biodiversidad/wwf.html#primerFecha de consulta: 30-10-2012.