A Mexican drive to save the vaquita marina appears to be failing as the snub-nosed marine mammal hurtles towards extinction.

The seemingly imminent demise of the smallest porpoise in the world is being blamed on illegal fishing to meet Chinese demand for the swim bladder of the totoaba fish, which also lives in the northern Gulf of California.

"We are convinced that we can still save the vaquita," Omar Vidal, director of the World Wildlife Fund in Mexico, told a press conference in the Mexican capital this week. "However, we also know for sure that this is our last chance of doing so."

There are currently only about 60 vaquitas left in the shallow nothern waters of the Gulf, the only place they live in the world, according to a new study released last Friday by the International Committee for the Recovery of the Vaquita, or CIRVA. Significantly fewer will be females of reproductive age that, scientists say, only give birth to a calf every two years.

The CIRVA is a team of scientists established by the Mexican government in 1996 when the mammal, discovered in 1958, was already identified as being in danger. The team's 2012 study calculated the vaquita population at 200 specimens using underwater sensors that detect the concentration of the creature's sonar squeaks. By 2014 the number had dropped by half.

The 2014 study prompted an intensification of the measures already in place to protect the animal. These included a two-year ban of fishing with gillnets, in which vaquitas get trapped, which came into effect in April 2015.

The other measures included a $70 million plan to compensate fishermen who use gillnets — large net walls that are left to hang in the water — while encouraging them to use less harmful nets, such as those used to catch shrimp. This are unlikely to snare the vaquita, turtles, and other endangered species.

The WWF's Vidal described the measures as "very ambitious" but not enough to stop illegal fishing that is pushing the vaquita to the verge of becoming the fifth marine mammal to go extinct since records began. The most recent was the Chinese river dolphin in 2006, before that the Japanese sea lion in 1970, that followed on from the Caribbean monk seal in 1952, and the Steller's sea cow in 1768.

"No one wants to kill the vaquita," Vidal said. "Their deaths are a byproduct of detrimental fishing practices."

The vaquita's plight is rooted in Chinese demand for the swim bladder of an endangered fish from the same area called the totoaba. Each bladder — the gas sack that regulates the buoyancy of the fish — reportedly fetches $10,000 dollars in the Chinese market, where it is regarded as a delicacy.

"If we don't stop the fishing of Totoaba, the vaquita will go extinct," Vidal said. "There is no time to wait."

The activist said this would require cooperation between the governments of Mexico, China, and the United States through which the dried fish bladders are believed to be smuggled. He also stressed that if the vaquita is allowed to disappear the whole habitat would be put in danger.

Mexico's environment ministry released a statement on Friday night recognizing the dangers to the vaquita, and insisting that the government is determined to save the porpoise.

While the statement mentioned that the current number of vaquitas stands at 60, it brushed over the fact that this represents a significant decline despite emergency measures.

The statement did, however, say that efforts would be redoubled in the face of the death of three vaquitas that were found in March by the Sea Shepherd Conservation Society. The discovery of the three dead porpoises has led some to suggest the surviving numbers of the vaquita could already be significantly lower than the total of 60 estimated in the latest study that concluded in December.