The Vaquita (Phocoena sinus), also known as the desert or gulf porpoise, is an endemic species at the northern part of the Gulf of California (Sea of Cortez). In July 2014, acoustic data showed that the number of this species have dropped below 100 individuals, making it currently the most endangered marine mammal in the world.
The Vaquita has the most limited distribution of all cetaceans. It is one of the six species of porpoise and it closely resembles the common porpoise. Stomach content analysis showed that it mainly feeds on demersal and benthic fish species, squids and crustaceans. Although the vaquita was only fully described in 1985, it is known that female individuals give birth once in every two years, and its maximum lifespan can be up to 21 years.
The population of vaquitas is very small and it is currently disappearing faster than expected. In the last few years their numbers dropped by about 18% per year. The primary reason of the decline is incidental bycatch (entanglement in gillnets and trawl nets). Gillnetting is intended to target the fish called totoaba, whose highly priced swim bladder is used as a traditional health food and medicine in China. Moreover, due to the damming of the Colorado River the habitat of this species had been altered, while pesticide pollution is also known to be a problem.
Due to the rapid decline of this species, an International Committee for the Recovery of the Vaquita (CIRVA, Comité Internacional Para la Recuperación de la Vaquita) was established by the Mexican Government in 1997. In 2005, the creation of a Vaquita Refuge Zone was suggested, however, this initiation failed as a consequence of financial issues. The fifth meeting of CIRVA was held in July this year, where the three main recommendations were: the establishment of gillnet exclusion zone starting in September 2014, the development of alternative fishing gears, and the launching of a continuous monitoring and research program.
After the loss of Steller’s sea cow, Caribbean monk seal, Japanese sea lion and baiji, vaquita can be the next marine mammal species to be driven to extinction by anthropogenic activities. Thus, CIRVA advised that with the help of US, Mexican and Chinese governments, conservation measures need to be taken immediately to save this species.
By Wanda Bodnar
Image source: Aquarium of the Pacific, Vaquita.tv, International Committee for the Recovery of the Vaquita.