The vaquita porpoise, the world’s smallest marine mammal, is headed for extinction. Biologists think that there are only 10 of these small porpoises left in the world. Vaquitas, which are 4 to 5 feet (1.2 to 1.5 m) in length and live only in Mexico's Sea of Cortez, are likely to die off completely if fishermen continue to use large mesh gillnets, which entrap the porpoises and lead to their deaths.
There is, however, a glimmer of hope. Evolutionary biologists studying the genomes of 20 vaquitas that lived between 1985 and 2017 have concluded that if gillnet use stops promptly, the vaquita is still relatively healthy and can survive – and probably thrive – even with inevitable inbreeding.
The versatile, vanishing vaquita:
- Researchers say the vaquita has survived for thousands of years with low genetic diversity, allowing the species “to gradually purge highly deleterious recessive gene variants that might negatively affect their health under inbreeding."
- Poachers use mesh gillnets to harvest totoaba, an endangered fish valued for its perceived medicinal properties. Mexico has outlawed totoaba fishing and made the use of these nets in the vaquitas' habitat illegal, but enforcement has been difficult.
- The vaquita is symbolic of the unique diversity found in the Sea of Cortez (also known as the Gulf of California), described by John Steinbeck in his 1951 book The Log From the Sea of Cortez.