Photo by Roberto Nistri/Alamy
Researchers are listening in on the vaquita, the most endangered marine animal, to find a way to save the species from extinction. Vaquitas emit calls every year, and this can tell researchers how many individuals are left.
The vaquita is a small porpoise that resembles a dolphin, often getting mistaken for the other cetacean. However, it's a different species entirely, though both species belong to the clade Cetacea. Porpoises, however, have short beaks and flat teeth, as opposed to the longer beaks and conical teeth on dolphins.
Unfortunately, the vaquita is on the brink of extinction. There were over 500 individuals in 1997, and a survey in 2015 found that there were fewer than 50 left. As of early this year, researchers found that the vaquita population is down to just about 30. In just 20 years, the vaquita population dwindled by over 90%. This rate of decline is quite worrying, and it led to the vaquita being the most endangered marine animal today.
Photo via The Yucatan Times
A team of researchers from Mexico's National Institute of Ecology and Climate Change spent four years, from 2011 to 2015, listening in on vaquita calls. The team placed 48 passive acoustic monitors in the Upper Gulf of California, in a spot known to be a vaquita haunt.
Vaquitas echolocate almost continuously, especially when they're on the hunt. However, these aren't sounds that we'll be able to hear unaided. Vaquitas emit sounds that are vastly different from the clicks that dolphins make, which we can easily identify. Previous research has found that porpoise calls come at a frequency that's too high for human ears to detect. Porpoises call at a frequency of about 135kHz, while humans can only hear frequencies of up to 20kHz, much lower than the frequency of porpoise calls.
According to the findings, the vaquita population declined at a rate of 34% per year. That's quite a fast rate, and it's unprecedented. “[I]n the same sampling site we used to have several detections of vaquitas per day,” says Armando Jaramillo Legorreta, one of the researchers. “Nowadays, we have only few or none.”
Thus, the vaquitas aren't doing so well. Scientists and conservationists are now working to save the species, but it may be a difficult thing to do.
The Yangtze river dolphin, which was driven to extinction by the same thing that's endangering the vaquita [Photo by Avalon/Alamy Stock Photo]
Jorge Torre of COBI, a conservation NGO in Mexico, says that the extinction of vaquitas can have a huge impact on the ecosystem as well as on humans. For one thing, it can cause fishermen to overfish. If this happens, fish populations will decline, which can then lead to the fishermen losing their livelihood.
Like dolphins, vaquitas have long been victims of getting accidentally caught in fishing nets, which is a phenomenon called bycatch. Gillnets in particular have been harmful to vaquitas, and they've even contributed to the extinction of the Yangtze river dolphin.
There have been efforts to save the most endangered marine animal in the world, and hopefully these efforts will keep the species from extinction. Conservationists have been reporting that they see more dead vaquitas than live ones, so these efforts need to be effective and efficient.
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