Posted on Sep 18, 2022 16
Efforts continue to crack down on illegal vaquita fishing, including removing illegal nets from the sea, monitoring the population, and trying to develop alternative fishing gear that is safer for vaquitas.
The vaquita is a marine mammal of the cetacean order known as the “porpoise”. It is distinguished by its small size, reaching a maximum length of one and a half meters, and is very similar to dolphins.
Because of the dark spots around the eyes, this porpoise looks like a cow. Hence its name: vaquita is a Spanish word of origin and translates as "little cow".
It lives only in the northern waters of the Sea of Cortez in Mexico. The vaquita was not known to science until the 1950s. Scientists Ken Norris and William McFarland published the first description of the species in 1958, based only on three turtles found ashore in the northern Cortez Sea.
The vaquita is a very secretive and rare animal. Its first photograph was taken in the 1980s. The murky, sediment-laden water in the northern Cortez Sea makes visibility underwater extremely low, and the vaquita navigates this environment with echolocation, as dolphins do.
Scientists have developed special hydrophones capable of recording high-frequency sonar signals emitted by vaquitas. This data is used to estimate changes in their population.
Three large-scale visual surveys were also conducted to determine the vaquita population, comparing the data with acoustic data on trends in the vaquita population over the entire observation period.
In 1997, there were about 567 vaquitas in the Sea of Cortez, by 2008 there were 245 individuals left, and by 2015, their population had declined to less than 60 individuals. In 2016, the number of individuals decreased by another 50%, reaching 30 animals.
The vaquita is currently the marine mammal most threatened by total extinction. In December 2018, there were only 15 individuals worldwide.
The reason for the dramatic decline in vaquita numbers is the use of gill nets by fishermen. Typically, vaquitas only surface for a second to breathe, but the nets entangle them, preventing them from surfacing.
One type of gill net has had a particularly devastating effect on the vaquita population - the nets used to catch totoaba fish, which are also endangered. Catching totoaba fish is illegal, but because of the high value of this fish’s swim bladder, it continues to be caught despite bans.
Totoaba swim bladders are used in traditional Chinese medicine as a tonic and medicine and have no proven therapeutic properties, but in recent years, their value has increased so much that dried canned bladders are now sold in China as a commodity for export.
Efforts to crack down on the illegal use of gill nets and illegal fishing for totoaba fish have been undermined by drug cartels involved in the totoaba fish swim bladder trade.
In 2017, the Mexican government, in cooperation with several nongovernmental organizations, including the National Marine Mammal Foundation, attempted to move some of the last remaining vaquitas to a temporary refuge. This unprecedented project involves an international consortium of marine mammal experts.
Two vaquitas were captured in the fall of 2017 by a team of zoologists to keep the animals in captivity. One had to be released a few hours after being caught because of concerns about unacceptably high levels of stress.
The second female died a few hours after being taken to a Mexican government-organized kennel. After her death, a decision was made to shut down the government’s vaquita conservation program.
We can conclude from this story that protecting rare animals should be started at the first signs of population decline, not when there are very few of them left.