The little cow of the sea –
meet the vaquita
With its 1.5 m in length, the vaquita is amongst the smallest cetaceans (a group that also consists of whales, dolphins, and porpoises). “Vaquita” means little cow in Spanish; the lovely black facial markings, the black lips and eye patches are its name-giving features. But it is not only the smallest swimming cow, it earned another sad superlative: the vaquita is the world's most endangered marine mammal!
The vaquita only lives in a small area in the northernmost part of the Gulf of California in Mexico. Vaquitas are shy and very inconspicuous animals. They only surface briefly to breathe and avoid motorised boats and ships. And still, in recent years, the vaquita has become the latest of many species on the verge of extinction because of human activity.
To estimate the population size, scientists chartered the research vessel Ocean Starr (former NOAA ship David Starr Jordan) in 1997, 2008 and 2015 for a series of visual surveys.
Especially because these shy and rare animals are so hard to spot, acoustic devices have been used since 2008 to estimate the population by the sounds that they produce. These sounds are echolocation clicks that the small porpoises use to navigate under the surface of the murky waters. Results from these survey efforts show that the vaquita population has recently declined to critically low levels. The population sizes dropped by 95% from 567 animals in 1997 to around 30 animals in 2016.
The main cause for their decline is the illegal fishing activity for totoaba bass (Totoaba macdonaldi) in their home range. Vaquitas get entangled in the gill nets used by local fishermen and drown. Researchers say that the vaquita will go extinct if the illegal fishing is not stopped. If you want to find out more about the threats to the vaquita, here is a documentary about its conservation.
Author and Illustrator: Dr Cornelia Oedekoven