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The world’s smallest porpoise is in dire straits. Only 30 individuals of the vaquita porpoise are left on the planet.

The population of vaquitas has dramatically dwindled since 2011. Between 2015 and 2016, almost half the remaining vaquitas died, and over the past five years, their numbers have decreased by a total of 90 per cent.

Vaquitas live exclusively in a small area in the Gulf of California, Mexico, where illegal fishing with gill nets is the main cause of their demise. Gill nets are commonly used by fishermen targeting the totoaba, another endangered species sought after in Asia for the supposed medicinal properties of its swim bladder.

“They’re essentially taking out two endangered species in one fell swoop,” says , a marine wildlife consultant at the Animal Welfare Institute. “We know what the problem is: it’s gill nets. We’ve known for 30 years that gill nets kill vaquita and we have done nothing, and I find that heartbreaking.”

Porpoise in peril

In 2015, the Mexican government enacted a two-year ban on gill nets that covers the home territory of the vaquita, but the law is not well enforced. A by the International Committee for the Recovery of the Vaquita (CIRVA) detailed 31 illegal gill nets in the range of the vaquita during a 15-day survey of the region in October and November 2016.

The ban also included a loophole that allowed gill nets to be used to catch corvina in legal fisheries, which makes it possible for the nets to disguise illegal totoaba fishing.

“As long as that loophole is there it’s unlikely we can do much to protect the vaquita,” O’Connell says. “We need a permanent ban on gill nets in the upper Gulf of California.”

The temporary ban is set to end in April and it’s unclear whether it will be extended, O’Connell says. To protect the vulnerable vaquita, CIRVA recommends a permanent ban on gill nets and stronger enforcement of illegal gill net fishing.

They also suggest that some vaquitas should be placed in a temporary sanctuary, though there has never been an effort to capture them and it’s unclear how they would respond to captivity.

O’Connell says that other marine mammal species have come back from extremely low numbers, including the northern elephant seal, which was nearly wiped out in the 19th century and has rebounded from less than 100 individuals to well over 100,000 today.

Saving the species

CIRVA also suggests that some vaquitas should be placed in a temporary sanctuary, and though most porpoises respond well to being captured, there has never been an effort to catch vaquitas so it’s unclear how they would respond to captivity.

Barbara Taylor at the National Oceanic and Atmospheric Administration says there’s a plan in place to catch some vaquitas as early as October 2017 and house them in captivity until it’s safe to return them to their natural habitat.

“We can’t afford to wait anymore. They’re going to be gone in a year or two,” she says.

It will be tricky to catch the vaquitas because they’re shy and tend to avoid humans and boats. The water they live in is fairly cloudy and on average vaquitas only gather in groups of a few animals. They’re so rare, Taylor says, “a lot of fishermen still maintain to this day that they’re mythical.”

To track these elusive creatures, researchers use a grid of acoustic monitors embedded in the sea floor to monitor the population size.

“Porpoises are compulsive echo-locators … they find their food by echo-locating like bats,” she says. Comparing the number of echolocation clicks heard underwater year-by-year gives researchers a good idea of how many individuals are left in the wild.

Dolphin posse

Because they’re tough to spot even with high-powered binoculars and expert observers, the round-up crew will use trained dolphins from the US Navy Marine Mammal Program to help find the vaquitas in the murky waters. Dolphins are easier to spot and approach with boats, so Taylor says the researchers can follow them to the elusive porpoises.

But the most difficult challenge is the race against time. Taylor says a successful expedition to capture the vaquitas requires funding, housing and veterinary care, as well as perfectly clear weather that won’t be available until after winter is over.

“Right now the clock is ticking, and we’re not winning,” she says.