Reduction of the delta's size has also threatened animals such as jaguars and the vaquita porpoise, which is endemic to the gulf.

With less vaquita porpoise individuals in the habitat, there will eventually be significantly less contact between the different sexes and consequently less reproduction.

But biologists say studies of the carcasses of the vaquita porpoises show no signs of malnourishment, but plenty of scars from fishing nets.

Though the major cause of vaquita porpoise mortality is bycatch in gillnets, numbers continue to dwindle and new factors will arise that will cause the population to further decline.

Other names include cochito, Gulf of California harbor porpoise, Gulf of California porpoise, and gulf porpoise.

He may be the only researcher to have worked with both the baiji and the presently highly endangered vaquita, or Gulf of California harbor porpoise of the northern Gulf of California, Mexico.

Among little-known mammals listed as critically endangered, the Gulf of California harbor porpoise or vaquita (Spanish for "little cow") has been reduced to around 100 individuals because of pollution, water diversion and entanglements in fishing nets.

The vaquita (Phocoena sinus) is a rare species of porpoise.

Vaquita (Phocoena sinus)

The vaquita (Phocoena sinus) is highly endangered and is endemic to the upper Gulf of California, Mexico.