vaquita

vaquita, (Phocoena sinus), species of nonmigratory marine mammal known for being the smallest member of the porpoise family, Phocoenidae, and the most endangered marine mammal species on Earth. Most researchers acknowledge that the vaquita population is made up of roughly 10 individuals; however, some assert that only 6−8 remain. The vaquita’s geographic range is limited to the northern Gulf of California, Mexico, where it is typically found in shallow lagoons relatively close to shore. The vaquita’s scientific name, Phocoena sinus, is Latin for “porpoise of the gulf,” while the mammal’s common name, vaquita, is Spanish for “little cow.”

Natural history

Vaquitas are dark gray along the back and light gray on the underside. Like many other porpoises, they have a rounded head, a blunt snout, and a blowhole. They have a triangular dorsal fin in the middle of the back, which is larger than the dorsal fin on other species of porpoise. The vaquita is recognizable for the dark patches around the eyes and on the mouth and a gray line from the mouth to each pectoral fin. Full-grown vaquitas can be up to 1.5 meters (5 feet) long and weigh 30−55 kg (66−120 pounds). Although female vaquitas have slightly longer bodies than males, males have slightly larger fins.

Unlike some other porpoise species, vaquitas do not form social groups. They tend to swim alone or in pairs near the water’s surface, and they tend to avoid boats and other watercraft. Their diet is made up of prey found near the surface, such as small fish, shrimp and other crustaceans, and squid.

Vaquitas are polygynous (meaning that a single breeding male mates with several females), and the annual breeding season is in April and May. After fertilization, females carry a single calf for 10−11 months and give birth in March the following year. Newborn calves are roughly 0.76 meter (about 2.5 feet) long and weigh 7.26−9 kg (16−20 pounds). They stay with their mother, drawing milk and benefiting from her protection, for much of the next year before they disperse. Both sexes become sexually mature between ages three and six, though unusually large individuals breed earlier. Vaquitas can live up to 21 years.

Conservation status

The International Union for Conservation of Nature and Natural Resources (IUCN) has classified the vaquita as a critically endangered species since 2007. The main threat to the animal is illegal gill net fishing in the Gulf of California. Though vaquitas are not hunted, their small size causes them to become easily trapped as bycatch in gill nets, which prevent them from reaching the surface to breathe. Prior to 1975, fishing for totoaba (Totoaba macdonaldi), a fish both Mexico and the United States considered to be endangered, resulted in high numbers of vaquita deaths. Although Mexico outlawed totoaba fishing in 1975 and the use of gill nets in 2015, lax enforcement of the law and the continued use of gill nets for other species contributed to precipitous declines in the vaquita population. Researchers note that vaquita numbers plummeted by about 98 percent between 1997 and 2018, falling from an estimated 567 individuals to 6−19. Much of this decline can be explained by the expansion of totoaba fishing after 2011, driven by Chinese demand for totoaba swim bladders, which are valued in traditional medicine and as a soup ingredient. By one estimate, a single kilogram (2.2 pounds) of totoaba swim bladder can fetch as much as $8,500, which is equal to a large percentage of a year’s wages for legal fishing in Mexico.