The vaquita is vanishing. Its population has fallen by 92 percent since the late 1990s, prompting scientists to warn in 2014 that the tiny porpoise could be extinct as early as 2018, with fewer than 100 left. And according to a May 2016 survey by Mexican wildlife officials, the total number of vaquitas on Earth is now down to about 60.

At roughly 4 feet long and 90 pounds, vaquitas are already the planet's smallest marine mammals — vaquita means "little cow" in Spanish — and now they're also the most endangered. This species is yet another victim of poaching and international wildlife trafficking, but with an odd twist: No one is actually trying to kill it.

Unlike sharks, rhinos and many other animals slaughtered by humans, vaquitas have no black-market value. Unknown to science until 1958, the species was probably never abundant, living only in a corner of the Gulf of California. But the shy porpoises began showing up in shrimp nets in recent decades, not unlike the way dolphins were once plagued by tuna fishing. And while conservationists push for shrimpers to adopt vaquita-friendly gear, that threat is now being eclipsed by something even worse.

"We could have dealt with shrimping," says Zak Smith, staff attorney for the Marine Mammal Protection Project at the Natural Resources Defense Council (NRDC). "There are thousands of people in that area who depend on the shrimp, but there are options for that. There is vaquita-friendly gear they could be using. But when the totoaba issue came into it, that changed everything."

totoabaThe totoaba is a humble fish that poses no direct danger to vaquitas. The problem is that it does have black-market value in China, where its swim bladder is believed to have medicinal properties. That has led to intensive totoaba fishing in the Gulf of California, aka Sea of Cortez, even after Mexico protected the endangered fish in the 1970s. And since poachers hunt totoaba with huge gillnets — the same kind of indiscriminate netting traditionally used by local shrimpers — they inevitably catch vaquitas, too.

While most shrimpers are just trying to make a living, the high price of totoaba has also lured Mexico's notorious drug cartels into the mix. Totoaba swim bladders can sell for up to $10,000 per kilogram, making them more lucrative than marijuana. And if the Mexican government has struggled to convince ordinary anglers not to use gillnets, its hopes of persuading cartel-backed poachers are faint.

"There's real money to be made there, and these organizations are well-established and use force when they have to," Smith tells MNN. "So you can't just go up and nicely ask them not to use gillnets."

vaquita range

The annual vaquita decline improved slightly in 2010, from 9 percent a year to less than 5 percent, but the surge in totoaba poaching has since pushed it back up to more than 18 percent. A 2014 study warned the species had lost half its population in two years, leaving just 97 vaquitas alive, and now the 2016 population is thought to be as low as 60. Some scientists worry that too few vaquitas remain in the wild to start a captive-breeding program, although the idea is being studied anyway.

Mexico has spent more than $50 million in recent years to save the vaquita, creating a 480-square-mile refuge in the Gulf of California and compensating local fishermen for lost income. In 2015, the government announced it would ban gillnets across 5,000 square miles of vaquita habitat for two years, buying more time for the development of vaquita-friendlier fishing nets. It also unveiled a $70 million plan to help anglers adapt, tasked the Mexican Navy with enforcement of vaquita protections, and stepped up surveillance with faster boats, aircraft and drones.

And as the outlook continues growing bleaker, the country's National Commission of Aquaculture and Fisheries announced in July 2016 that it will "permanently" ban gillnets across remaining vaquita habitat. The measure takes effect in September 2016, and on top of banning gillnets known as chinchorro line, it would also ban night fishing and impose other rules meant to protect the rare cetaceans.

These moves are vital for vaquitas, scientists and conservationists say, but they may still not be enough. "We are watching this precious native species disappear before our eyes," says Lorenzo Rojas-Bracho, chair of the International Committee for the Recovery of the Vaquita (CIRVA), in a statement. "Our latest survey confirms the catastrophic decline before the emergency gillnet ban. This gillnet ban and strong enforcement must continue if we are to have any hope of saving the vaquita."

Poachers still haven't given up on using gillnets in vaquita habitat, despite growing scrutiny from Mexican authorities as well as the international community. They often venture out at night, and reportedly stay ahead of patrol boats with help from lookouts based on shore. A survey in late 2014 revealed aerial imagery of gillnet fishing boats inside the vaquita refuge, and this April 2016 drone video shows a boatful of totoaba poachers realizing they've been caught in the act:

"The fisheries agencies do have limited resources," Smith says, noting the refuge is "small compared to the whole Gulf of California, but it's still a lot to patrol by boat."

Even with a permanent gillnet ban, the vaquita probably can't be saved by Mexico alone. An effective solution will also need to involve the U.S. and especially China, Smith adds, since shrimp netted in the Sea of Cortez are often exported, and totoaba bladders are often smuggled into California before they're shipped across the Pacific.

New U.S. regulations could help, requiring all imported seafood to comply with federal marine-mammal laws. The rules were promised in January 2015 as part of a settlement with the NRDC and several other conservation groups, implementing a decades-old provision of the U.S. Marine Mammal Protection Act that could improve fortunes for many of the 650,000 whales, dolphins, porpoises and other marine mammals that are fatally entangled in fishing gear around the world every year.

"The new regulations will force other countries to step up and meet U.S. conservation standards — saving hundreds of thousands of whales and dolphins from dying on hooks and in fishing nets around the world," says Sarah Uhlemann of the Center for Biological Diversity. "The U.S. government has finally recognized that all seafood consumed in the United States must be 'dolphin-safe.'"

vaquitas Vaquitas are typically found alone or in pairs, but they may swim in groups of up to 10. (Photo: Paula Olson/NOAA)

This might be too late to help vaquitas, Smith notes, since the rules won't be finalized until August 2016 and will likely involve a phase-in period that could stretch beyond 2018. "However, in settling the case we did preserve the option to sue specifically on vaquita after June 1, 2015," he adds. "So if we don't see adequate action on the side of the U.S. or in Mexico, we will have that option to sue for immediate implementation with respect to vaquita. We'll have to see if that's necessary."

The elephant in the room is still China, however, since that's where most global demand for totoaba comes from. China isn't exactly known as a leader in wildlife conservation — not only does it help fuel global demand for elephant ivory, rhino horn, shark fins and other unsustainable wildlife products, but it's also home to the most recently extinct marine mammal, the Yangtze river dolphin. Vaquitas are now considered the rarest marine mammal on Earth only because the Yangtze river dolphin, aka "baiji," was declared functionally extinct in 2007.

"A lot of people were alarmed by what happened to the Yangtze river dolphin, but now it's happening again in our own backyard," Smith says. "And it's entirely preventable. There's not a big trade-off. You can still keep shrimping; you just need to use different gear. We shouldn't see any marine mammal species go extinct in North America on our watch in this day and age."

Editor's Note: This story has been updated since it was first published in January 2015.

Russell McLendon ( @russmclendon ) writes about humans and other wildlife.