Mexican authorities faced calls to ban all fishing in the upper Gulf of California or permanently prohibit gillnets to save the vaquita marina, the world's smallest porpoise, from extinction.
Concerns about the vaquita's fate rose on Friday when scientists warned that only 60 of the sea creatures were left and could vanish by 2022 even though the navy has been patrolling their habitat.
In reaction, the World Wildlife Fund called for a full fishing ban in the vaquita's northwestern Mexico refuge.
The porpoise's population had already fallen to fewer than 100 in 2014, down from 200 in 2012, according to scientists at the International Committee for the Recovery of the Vaquita (CIRVA).
The vaquita's fate has been linked to another critically endangered sea creature, the totoaba, a fish that has been illegally caught for its swim bladder, which is dried and sold on the black market in China.
Poachers use illegal gillnets to catch the totoaba. The vaquita, a shy 1.5-meter-long (five-foot) cetacean with dark rings around the eyes, is said to be the victim of bycatch.
President Enrique Pena Nieto imposed a two-year ban on gillnets in April 2015 and increased the vaquita protection area tenfold to 13,000 square kilometers (5,000 square miles).
Pena Nieto also deployed navy reinforcements to enforce the ban.
The government is compensating fishermen to the tune of $70 million over two years for giving up gillnets while new methods are sought.
Fishermen in 'crisis'
But Omar Vidal, Mexico director of the World Wildlife Fun, said the measures have been "insufficient" and that fishermen have "camouflaged" gillnets with other legal nets.
An immediate fishing ban, he said, "can save the vaquita."
"It's a drastic measure but maybe the most efficient way is to prohibit fishing and obviously compensate fishermen," he told a news conference.
Mexico's environment ministry did not respond to requests for comment on the proposal.
Sunshine Antonio Rodriguez Pena, president of the fishing cooperative of the port of San Felipe, said his group would lodge a complaint before the United Nations if a fishing ban were to be imposed.
"They are completely crazy," he told AFP, noting that legal fishing includes corvina and clams and local fishermen are already in a "crisis."
"They should just declare (the vaquita) extinct because fishermen are not killing it," Rodriguez told AFP, saying other factors are to blame, such as predators, red algae or toxins.
For its part, CIRVA is calling for the two-year gillnet ban to become permanent.
Barbara Taylor, co-chief scientist of CIRVA's latest study, told AFP that it would take until 2075 to see the vaquita return to 1997 levels, when there were more than 500.
While three were found dead in March, she said it is likely that more died this year because most carcasses are not recovered.
Taylor, a scientist at the US National Oceanic and Atmospheric Administration, said CIRVA members were "thrilled and relieved" when they spotted vaquitas last fall as "we knew there had been a catastrophic decline and feared we may see none."
"However, it was clear that we had few sightings and that the new numbers would confirm the results from acoustic monitoring that illegal fishing had brought vaquitas to the brink of extinction," she said.
CIRVA chairman Lorenzo Rojas-Bracho, of Mexico's Natonal Institute of Ecology and Climate Change, said there's still hope for the vaquita as other national treasures have recovered in the past, such as elephant seals, which once numbered 20 and now number more than 150,000.
© 2016 AFP