Monitoring results from Mexico’s Upper Gulf of California have delivered one of the rarest sights in conservation: vaquita calves.
The vaquita (Phocoena sinus) is the world’s most endangered cetacean, found only in a 4,000 km² patch of the northern Gulf of California between Baja California and mainland Mexico. Numbers crashed from the hundreds in the late 1990s, and the species even triggered the International Whaling Commission’s first-ever “extinction alert” a couple of years ago. And yet against grim projections, the vaquita is still here.
What the 2025 survey found
In a survey carried out by Mexican authorities alongside expert researchers and Sea Shepherd Conservation Society, observers used an “expert elicitation” approach to estimate how many distinct animals were seen. The result: a 67% probability that 2025 observations represent between seven and 10 different vaquitas (compared with a 75% probability of six to eight in 2024). Most importantly, teams recorded at least one - and possibly two - calves.
One mother-calf pair included a recognisable female nicknamed “Frida”, identified by her bent dorsal fin. Frida has been documented with calves in previous years, and this year’s monitoring also noted a calf that appeared to be about a year old - an encouraging sign because the first months of life are especially perilous for such a tiny population.
How do you count an animal that doesn’t want to be found?
Vaquitas are small, inconspicuous and shy, so the 2025 effort combined acoustic monitoring with careful visual surveys. Sea Shepherd reports 1,228 acoustic detectors deployed across 497 sites, recording 254 acoustic encounters between 24 May and 29 September. Visual monitoring then ran from 2–30 September aboard two vessels (Seahorse and Bob Barker), with 25× “Big Eyes” binoculars used to spot animals at distance and minimise disturbance.
Why gillnets - and the totoaba trade - still matter
The big threat remains gillnets. Vaquitas were first lost as accidental bycatch in nets set for shrimp, and later in illegal gillnets used to target totoaba fish - prized for their swim bladders in lucrative black markets. Although gillnets were permanently banned in the Gulf of California in 2017, illegal use has persisted, prompting a “zero-tolerance” area where fishing is prohibited across key parts of the vaquita’s range, alongside international efforts through CITES to curb totoaba supply and demand.
A marine biologist not involved in the survey described the rise as a “reason for cautious optimism,” while Mexican officials emphasised that monitoring data help target vigilance and protection in precise areas.
Hope, with a hard edge
Seven to 10 animals is hardly a recovery - it’s a razor-thin lifeline. But calves mean something profound: conditions have been good enough, at least for now, for mothers to carry and raise young, and for protective measures to hold the line against further collapse.
The takeaway is clear: keep gillnets out, keep enforcement strong, and keep pressure on the illegal totoaba trade - because with so few animals left, each vaquita is priceless.
The only way we can protect whales and dolphins is by understanding their distribution, and so monitoring is vital for effective conservation. Donate today to help ORCA continue to identify and study important whale hotspots around the world