They are on the brink.
The world’s most endangered sea mammal is one many people will not have heard of, but only a handful of vaquitas are left on the planet.
Found only in the upper Gulf of California on the west coast of Mexico, these tiny porpoises – just five feet long – are down to just a handful of animals.
The results from the latest annual survey revealed only between six and eight individuals were seen, down from the eight to 13 spotted a year earlier.
No calves were witnessed by observers, although one yearling, born in 2023, appeared to be thriving.
Vaquitas, the smallest member of the cetacean family – which includes whales and dolphins – were only discovered in the 1950s, first identified by marine biologist Kenneth Norris using just a skull washed up on the beach.
Alongside their diminutive size, they are also secretive, spending most of their time below the waves in pairs, avoiding showy behaviour such as leaps and breaches. This has not only kept them hidden from human view seemingly for thousands of years, but makes it very hard to know exactly how many remain.
However, their limited habitat, in the warm waters of the gulf, also means they are prone to becoming caught in gillnets, long curtains of net that hang from a line of floats. When the vaquitas become tangled in the nets they are unable to surface and breath, causing them to drown.
In the Gulf of California, many of the gillnets are illegally set to catch another at-risk species, the totoaba – a fish caught for its swim bladders which are sought after in China.
Driftnets set for blue shrimp are also responsible for a number of vaquita casualties.
However, in recent years the Mexican government has set up a protected area – the Zero Tolerance Area (ZTA) – where fishing is completely banned in a bid to save the species.
The vaquita is the world’s rarest marine mammal.
Rarely spotted, the porpoises have a dark ring around their eyes and dark patches on their lips that stretch to their pectoral fins.
The animals are a dark grey on top and light underneath, known as countershading.
They are thought to have descended from Burmeister’s porpoise, found off the coasts of Peru, Chile and Argentina. It is thought during a period of global cooling a group separated and swam up the gulf. When the seas warmed again they were unable to swim back down and into the Pacific, instead evolving into their own distinct species.
The team searching for the vaquitas, organised by vaquita charity Sea Shepherd, focused their efforts around the ZTA, but also noted that half of the sightings were outside the zone.
Dr Barbara Taylor, leader of the survey, said: ‘While these results are worrying, the area surveyed represents only 12% of the total area where vaquitas were observed in 2015. Since vaquita move freely within the Vaquita Refuge, we must extend the survey using acoustic detection to determine where the vaquitas are going.
‘Vaquitas outside the sanctuary will need protection from ongoing gillnetting.’
The survey was carried out using underwater acoustic listening devices to try to locate animals, followed by visual surveys by experienced observers on board two boats.
The team said it will now extend the survey through July and into August.
