SAN FELIPE, Mexico, March 18 (Reuters) - The vaquita, a tiny stubby-nosed porpoise found only in Mexico's Sea of Cortez, is on the brink of extinction as more die each year in fishing nets than are being born, biologists say.

A drop in vaquita numbers to as few as 150 from around 600 at the start of the decade could see the famously shy animal go the same way as the Chinese river dolphin, which was declared all but extinct in 2006.

"The urgency now is to prevent the vaquita becoming extinct," Omar Vidal, the WWF conservation group's director in Mexico, told Reuters in San Felipe, a fishing town in the upper Gulf of California, or Sea of Cortez, where the vaquitas live.

"The latest studies suggest that we have perhaps one or two years for that," said Vidal, one of a team that has been battling to preserve the species for over 10 years.

The world's smallest porpoise, growing to a maximum of 5 feet (1.5 meters) long and gray in color, vaquitas are so timid that they are hardly ever sighted.

Click here to read the complete story on Reuters.