The world’s smallest marine mammal is so critically endangered that there are only about 10 remaining in its sole habitat of Mexico’s Gulf of California.
But that may not yet spell doom for the vaquita porpoise, according to new research.
Vaquitas have been pushed to the brink of going extinct due to illegal gillnetting, which is used to capture shrimp and totoaba fish that share the same habitat as the porpoises. The vaquitas, about 4 to 5 feet (1.2 to 1.5 meters) in length, end up as “bycatch” since they aren’t the intended target of the nets.
The totoaba fish, whose status is vulnerable on the International Union for Conservation of Nature Red List of Threatened Species, has a swim bladder that is prized in China and used for traditional medicine — and even seen as a financial investment. Mexico has outlawed totoaba fishing and made gillnetting illegal where the vaquitas live, but the practice continues unabated.
With such a small population left, researchers have questioned if vaquitas were at a greater risk of extinction due to inbreeding.
Scientists Barbara Taylor and Lorenzo Rojas-Bracho, who have been studying this risk for more than 20 years, published a 1999 paper suggesting that the “doom hypothesis” of inbreeding could not be confirmed. This is important because if an animal is considered “doomed to extinction” for this reason, conservation efforts may not be pursued, Rojas-Bracho said.
Now, a team of scientists has studied genetic patterns from vaquita tissue samples collected between 1985 and 2017 by Mexican researchers. Taylor is a senior scientist at the Oceanic and Atmospheric Administration’s Southwest Fisheries Science Center in La Jolla, California, and Rojas-Bracho is a conservation biologist and member of the National Commission of Protected Areas in Mexico.