Vaquita/Gulf of California porpoise

Vaquitas are often bycatch in gillnets where they drown. Only a few hundred animals are left.

The Mexican government has created a marine protected area in the northern Gulf of California, the only region where the vaquita occurs, to conserve this species, but it may be too late.

The Gulf of California porpoise is the cetacean (whales, dolphins, porpoises) with the most restricted distribution. Additionally the International Committee for the Recovery of the Vaquita (CIRVA), consisting of recognized whale scientists from UK, Canada, U.S. and Mexico, was established to develop a recovery plan for the vaquita and to collect more information e.g. about details in distribution of this species. This is a basis for the identification of sensful borders of the marine protected area. For many years the marine protected area has not included the core habitat of the vaquita. Most sightings of the animals were outside. In December 2005, the Mexican Ministry of Environment declared a vaquita refuge that contains the area in which 80% of the sightings were made. The state governments of Sonora and Baja California offered $1mio to compensate affected fishermen.

Other threats than bycatch which the vaquitas face are e.g. disturbance by trawlers which change the behaviour of the vaquitas and habitat destruction. Since the Colorado dam was constructed, freshwater supply to the northern Gulf of Caliornia is decreased which changes the habitat in ways which are not fully understood yet.

The habitat of the vaquita is characterized by shallow, turbid waters with strong tidal currents which mix the water quite well. Therefore nutritions stay in the water column, where they are available for use by animals and algae, instead of sinking down to the sea floor. The Gulf of California porpoise feeds on a high variety of fishes, but also on squid and crustaceans. Often passive acoustic is used to search for prey which means the vaquita waits for sounds produced by fishes instead of echolocating itself.

Little is known about the vaquita since this species is difficult to observe and scientific effort to close the big research gaps was low until about 20 years ago. The vaquita is a very small porpoise with a big shark-like dorsal fin (fin on the back). Like other porpoises it has a rounded head and massive body. Vaquitas are shy and usually avoid boats. The blow is small and more audible than visible. Since these porpoises are fast and elusive it is very hard to see them. Vaquitas do not spend much time on the water surface and jump around like most dolphin species do.

Groups of vaquitas are very small. Often only two animals are seen together but schools can consist of up to 10 animals. Sometimes these porpoises build loose aggregations which however are not stable. The oldest reported vaquita was 21 years old, which is a typical maximum age for porpoises.

Vaquitas are sexual mature with 3-6 years of age. Breeding is seasonal with most births in March.