Vaquita: between seven and ten individuals, and births all the same

The vaquita is the rarest marine mammal in the world. It lives only in one corner of the Gulf of California, it has never been numerous, and the number left today can be written without rounding: between seven and ten. The 2025 survey nevertheless brought back something the previous year had not produced: births.

What the latest survey reports

Different individuals sighted in 2025	7 to 10
Births	observed, after a year in 2024 with none at all
Number observed in 2024	8, the lowest ever documented
Estimated population in 1997	about 567
Full abundance estimate	expected in 2026

A point of method is needed before any reading of these figures. The seven to ten figure is not a population estimate: it is the minimum number of different individuals actually seen within a restricted search area, established by a panel of experts who compare photographs and encounters to avoid counting the same animal twice. The abundance estimate proper, with its interval, will come later.

The distinction is not cosmetic. A minimum count can only underestimate, since an animal never encountered does not appear in it. It gives a floor, not a value.

Searching for an animal this rare

Searching for a handful of individuals across a sea calls for particular methods, and the surveys combine two of them.

The first is visual. Observers stationed high up on small vessels sweep the surface with high-magnification binoculars. The vaquita is inconspicuous, it does not breach, its blow is brief and its dorsal fin small. Encounters are counted in single figures per survey.

The second is acoustic. Moored detectors record echolocation clicks continuously, and their signature is specific to the species. This approach covers the night and bad weather, and provides a trend index independent of the human eye, as our page on passive acoustic monitoring explains.

The two methods do not measure the same thing. The visual one identifies individuals, the acoustic one counts detections. Their agreement is what gives confidence in the figure put forward.

The cause, and why it has nothing to do with the vaquita

The vaquita is not hunted, it is not eaten, and nobody targets it. It dies from a fishery that has nothing to do with it.

The totoaba is a large fish endemic to the same gulf, whose dried swim bladder sells for very high prices on some Asian markets, where it is credited with medicinal properties. It is caught with wide-mesh gillnets, and a vaquita that swims into one drowns.

The mechanism is that of all bycatch, except that the commodity is of very high value, which makes the illegal fishery hard to discourage. Our page on bycatch and our detailed answer on the vaquita and the totoaba describe this chain.

The zero tolerance area

The regulatory response fits inside a small rectangle. A zero tolerance area has been drawn where the last encounters are concentrated, with a total ban on gillnets and reinforced surveillance.

The arrangement has one advantage and one weakness. The advantage is that it concentrates limited means where they count. The weakness is that it assumes the animals stay inside it, which nothing guarantees, and that the surveillance holds, which depends on the resources of the Mexican state and on the presence of non-governmental organisations that remove the nets.

The 2017 capture attempt

One episode is worth recounting, because it closed off an option and because it explains why in situ protection is now the only route.

In 2017, faced with the collapse in numbers, an international programme attempted to capture vaquitas in order to place them in a protected sea pen until the situation with the nets improved. The operation mobilised dozens of specialists, veterinarians and dolphins trained in detection.

Two animals were caught. The first, a juvenile, showed immediate signs of distress and was released. The second, an adult female, died shortly after capture, of cardiac arrest linked to stress. The programme was halted.

The conclusion drawn is clear: the vaquita does not tolerate handling, and conservation in captivity is not an option for this species. Every solution therefore runs through the removal of nets from its habitat.

This failure weighs on the broader debate about ex situ conservation of cetaceans. It is a reminder that what works for some mammals does not carry over, and our page on captivity and sanctuaries sets out these limits.

Why these births matter, and how far

The fact that females are giving birth is the best news available, for a precise reason.

A very small population can suffer from what biologists call inbreeding depression: genetic impoverishment produces less viable calves, and breeding ceases to be effective well before the last individual dies. It is one of the mechanisms that make extinction almost unavoidable below a certain threshold.

Genomic work on the vaquita, however, suggests that the species has always been few in number, and that it has purged part of its deleterious variants over time. It would therefore be less vulnerable to this mechanism than its numbers might suggest. The births observed in 2025 point in that direction.

This says nothing about mortality. A population that breeds normally still disappears if adults die in nets faster than they are replaced. Our pages on demographics and life cycles set out this balance.

The limits of what is known

Three uncertainties bear on any reading of these figures.

1. The area covered is small. The surveys concentrate on the sector where the species has been seen recently. Individuals living elsewhere would escape the count, a hypothesis judged unlikely but not ruled out.

2. A minimum count is not an abundance. Comparing seven to ten in 2025 with eight in 2024 does not have the rigour of a comparison between two estimates, and does not allow a rise to be concluded.

3. Mortality in nets is not measured. It is known to continue, at what rate is not known, because a vaquita carcass has little chance of being found.

Why this case is worth following

The vaquita is the exact counter-example to the Yangtze finless porpoise, whose January 2026 census gives 1,426 individuals after a fishing moratorium applied across an entire river basin. Same family, same kind of threat, an intervention in one case, a late and poorly enforced intervention in the other.

The fact remains that the species is still here, eight years after the first announcements of its imminent disappearance. Our page on conservation statuses puts this Critically Endangered category in context, and the one on how to act lists the reporting schemes.

Sources: vaquita research surveys conducted in the Gulf of California from May to September 2025; work by NOAA and the International Committee for the Recovery of the Vaquita; the full abundance estimate for 2025 is expected during 2026.

Photo credit: Photo from Museo de la Ballena, La Paz, Baja California Sur, México. This photo is use for enviromental education. Licence: CC BY-NC 4.0 © cris_bcs, attribution required in case of reuse.