When a species falls to a few dozen animals, the usual last resort is to bring some into human care and breed them, as was done for the California condor and the black-footed ferret. For the vaquita, the small porpoise of Mexico’s upper Gulf of California, scientists tried exactly that in 2017. It did not work, and the reasons why tell us a lot about porpoises, about the limits of captive rescue, and about what really has to happen for the vaquita to survive. This page covers whether vaquitas are kept in captivity, what happened during the VaquitaCPR project, and where things stand now. For the species itself, start with our vaquita facts page.

Has a vaquita ever been in captivity?

No. There are no vaquitas in any aquarium, zoo or sea pen, and there never have been, apart from the few hours during the 2017 rescue attempt.

The vaquita was only described scientifically in 1958, and for decades it was known mostly from skulls and from animals that drowned in fishing nets. It lives only in a small corner of the northern Gulf of California, in shallow, murky water, and it is shy and very hard to see. Nobody ever tried to keep one for display. By the time people seriously considered bringing vaquitas into human care, it was as an emergency measure, because the wild population was collapsing.

That’s different from some of its relatives. Harbor porpoises and finless porpoises have been kept in aquariums in Europe and Asia, and Yangtze finless porpoises have even bred in captivity. Those successes were part of the reason scientists hoped vaquitas could be held too. But they were working with species where animals could be caught relatively easily, and where there was room for trial and error. With the vaquita, there was neither.

Why VaquitaCPR was launched

By 2016, acoustic monitoring and visual surveys showed the vaquita population had fallen from several hundred in the late 1990s to around 30 animals. The cause was clear: vaquitas drown in gillnets, and illegal gillnets were being set in huge numbers to catch the totoaba, a large fish whose swim bladder sells for very high prices in Asian markets. Mexico had banned gillnets in the vaquita’s range, but enforcement could not keep up.

Faced with a population that could vanish within a few years, Mexico’s environment ministry, SEMARNAT, approved an emergency plan. An international team of marine mammal scientists and veterinarians, coordinated with the US-based National Marine Mammal Foundation, would try to locate vaquitas, catch them, and move them to a floating sea pen in a protected bay. There they would be safe from nets until the threat in the wild could be removed. The project was called VaquitaCPR, short for Conservation, Protection and Recovery. Trained US Navy dolphins were brought in to help find vaquitas acoustically, though they were not used to catch them.

What happened during the rescue

VaquitaCPR began field operations in October 2017. The first vaquita captured was a young female, estimated at around six months old. She was placed in a temporary floating enclosure, but she showed clear signs of stress, swimming erratically and failing to settle. Following the protocols the team had agreed in advance, veterinarians decided to release her the same day, and she swam away.

In early November, the team caught a second vaquita, an adult female who was not pregnant or nursing, the kind of animal the program most hoped to protect. She too became stressed in the sea pen. The team decided to release her, but she died within hours of capture despite the efforts of the veterinarians. A necropsy pointed to a cardiac failure linked to the stress of capture, a known risk in wild cetaceans called capture myopathy.

After her death, the experts concluded that the risk of killing more vaquitas was too high. With so few left, losing even one breeding female was a serious blow. The capture phase of VaquitaCPR was ended, and the focus returned entirely to protecting vaquitas in the wild.

Why vaquitas cope so badly with captivity

Scientists had known the attempt was risky. Porpoises in general are nervous, highly strung animals compared with dolphins. They have fast metabolisms, need to eat almost constantly, and can react to capture with severe stress responses that affect the heart and muscles. Even harbor porpoises, which have been kept successfully, do not always adapt, and early attempts to keep porpoises often ended badly.

The vaquita adds more problems. It had never been handled before, so there was no experience of how individuals would react. The team could not practise on spare animals, because there were none. Catching them was also extremely difficult: vaquitas avoid boats, live in turbid water, and surface briefly. And every vaquita was precious. In a population of about 30, a single death represented a measurable share of the species.

The decision to stop was criticised by some and supported by most experts. It highlighted a painful truth in conservation: captive rescue is a tool that works best when it is started early, while there are still enough animals to absorb losses and learn from mistakes.

Species	Kept in captivity?	Bred in captivity?	Notes
Vaquita	No (only hours in 2017)	No	Capture attempt stopped after one death
Harbor porpoise	Yes, in a few European facilities	Yes, occasionally	Mostly rescued stranded animals
Finless porpoises	Yes, Japan and China	Yes	Yangtze form bred in Wuhan
Dall’s porpoise	Rarely, short-lived	No	Fast offshore species, did poorly in tanks

Could captivity ever be tried again?

In principle, yes, but most experts think the window has closed. With only around ten animals left, every individual matters far more than it did in 2017, and nothing about the vaquita’s reaction to capture has changed. The equipment, sea pen and veterinary team could be assembled again, but the same stress response that killed the adult female would still be there, and there would be even less room for error.

There are also practical limits. Finding a vaquita in the first place is now extremely difficult; survey teams spend weeks on the water to record a handful of sightings. Catching one requires calm seas, clear coordination and a lot of luck, and every hour of pursuit adds stress to the animal. For those reasons, the international committee that advises on vaquita recovery has recommended putting all effort into eliminating gillnets rather than revisiting capture. The survivors are breeding in the wild, which is the best evidence that the habitat itself can still support them if the nets are gone.

Is the vaquita extinct?

Not yet. After VaquitaCPR, survey teams have continued to search for vaquitas each year using visual observers and underwater acoustic detectors. Population estimates fell further, to fewer than 20 by 2018 and to around ten in the early 2020s. Remarkably, more recent surveys have still found a small number of vaquitas, including some calves, which shows the survivors are healthy and still breeding.

That is the one hopeful fact in the story. Studies of vaquita genetics suggest the species has naturally low genetic diversity but is not doomed by inbreeding, so if gillnet deaths stop, the population could in theory recover. The vaquita is listed as Critically Endangered by the IUCN, and it remains one of the rarest sea animals on Earth.

What is being done instead

With captivity ruled out, everything depends on making the vaquita’s small home safe. Mexico declared a “zero tolerance” area in the core of the remaining habitat, where fishing is banned and enforcement is concentrated. Concrete blocks have been placed on the seabed in parts of this area to snag and deter illegal gillnets. Net-removal teams, including conservation groups working with local fishermen, pull out abandoned and illegal nets. Researchers and fishermen have also tested alternative fishing gear that catches shrimp and fish without entangling porpoises.

The deeper problem is the illegal totoaba trade. As long as totoaba swim bladders fetch high prices, organised networks will keep setting nets in the Sea of Cortez. International pressure through CITES and on the trade routes to Asia is part of the solution, alongside giving fishing communities a reliable income that doesn’t depend on gillnets.

My view as a coral farmer on captive rescue

I’ve run a coral farm and grown corals in stock tanks for years, so I’m a big believer in captive propagation where it works. With many corals, you can take a fragment, grow it out, and produce dozens of new colonies, which takes pressure off wild reefs. That’s a real conservation tool. But the vaquita story is a reminder that it doesn’t work for everything. A coral fragment can tolerate a lot of handling. A wild porpoise that has never seen a net pen is a completely different animal.

What I take from VaquitaCPR is that the people involved made a hard, honest call. They tried something risky because the alternative looked like extinction, and when it went wrong they stopped instead of gambling with more animals. If there’s a lesson for other species, it’s to plan backup populations early, while numbers are still large enough to learn. For the vaquita, the only real answer left is the one that was always needed: get the gillnets out of the water. For more on why so many marine mammals ended up in this position, see why the Marine Mammal Protection Act was created, and for the vaquita’s closest relative, see Burmeister’s porpoise.