As both the smallest and most endangered marine mammal in the world, the Vaquita has been classified as critically endangered by the IUCN since 1996 and experts say there may only be about 10 individuals left, despite extensive conservation efforts. Their biggest threat is from the illegal gillnet fishing of Totoaba, a large fish in demand because of its swim bladder. Conservation efforts led to the introduction of a ban on gillnets in Vaquita habitat back in July 2016, but illegal fishing continues, and the threat remains.