Mexico - 'Cocaine of the sea' threatens critically endangered vaquita
The vaquita marina is found only in Mexico. It is the most critically endangered sea mammal on the planet, its survival threatened by a deadly clash of interests between fishing and conservation. Scientists estimate there may be fewer than a dozen left in the wild.
Jacques Cousteau, the marine explorer, called the Sea of Cortéz, also known as the Gulf of California, "the world's aquarium".
One of its treasures is a silvery-coloured porpoise with wide, panda eyes. But the vaquita's days may be numbered because of illegal fishing for another protected species: totoaba.
Totoaba, a fish that can grow as large as a vaquita, was a food source before it was placed on Mexico's endangered list.
"We used to catch it in the 60s and 70s," remembers Ramón Franco Díaz, president of a fishing federation in the coastal town of San Felipe, on the peninsula of Baja California. "Then the Chinese came with their suitcases full of dollars, and bought our consciences."
They arrived wanting the totoaba's swim bladder, an organ that helps the fish stay buoyant. In China it is highly prized for its perceived - though unproven - medicinal properties.
According to the Earth League International NGO, 10-year-old dried swim bladders can sell for $85,000 (£60,000) a kilo in China. The fishermen of San Felipe make only a tiny fraction but in a poor community, business has boomed for the "cocaine of the sea".
"The illegal fishermen - the criminal elements - are so strong that in the plain light of day you see them with their illegal nets and totoaba," says Mr Franco Díaz.
Every afternoon during the season, a stream of pick-up trucks towing fishing boats reverses down the concrete slipway of the town's public beach and into the sea. These craft are mostly unlicensed, and their crew use nets that can kill the vaquita.
"Gillnets might be hundreds of metres long and 10 metres high," says Valeria Towns, who works with a Mexican NGO, Museo de la Ballena. "They become a wall under water."
To protect the vaquita, all gillnets are banned in the upper Gulf. However, they are widely used, even by fishermen with permits for halibut or prawns. Mesh size varies with the catch, and the most perilous to the vaquita are gillnets with large mesh used for totoaba.
"It's not easy for marine mammals to free themselves from those - the vaquita get caught," says Ms Towns.