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6/13/21

Vaquita

The vaquita, or Phocoena sinus, is a shy species of porpoise and unfortunately is also the world’s rarest marine mammal. They are only found in the northern Gulf of California in Mexico in a small 1,519 square mile area. In fact, they have the smallest range of any marine mammal. They are 5 foot long, dark grey porpoises with white and grey markings on their undersides. Young vaquitas are darker and have a grey fringe. Females are longer than males, but males have larger fins. Vaquitas also have larger dorsal fins than other porpoises, possibly there reduce body temperature. It is hard to find and observe vaquitas because they travel alone or with pairs, avoid boats, small size, and when they come up for air, they barely break the surface. Vaquitas can live up to 21 years. Females give birth every other year, and pregnancy lasts between 10-11 months. They eat small fish, crustaceans and cephalopods. They were first documented in 1958, and have experienced a rapid decline since. In 2016, an estimated 30 vaquitas remained; in 2018, 19 were left; and the most recent 2020 estimates suggest that less than 10 vaquitas remain.

There is only one reason for the vaquita’s decline: bycatch in fishing gear. Although researchers have considered other reasons such as lack of Colorado River flow decreasing prey, pollutants, and low genetic diversity, no examined vaquitas show signs of malnutrition, pollutants, or inbreeding; in fact, vaquitas have one of the lowest levels of pollutants in their environment.

Vaquitas are mostly threatened by bycatch in gillnets, a type of fishing gear used for catching a critically endangered fish, totoaba, as well as for shrimp and other fish. Totoaba and vaquita are similar sizes, so vaquita are often caught and killed in the totoaba gillnets. Although fishing for totoaba is illegal and use of gillnets has been banned from many places, illegal fishing still continues. The totoaba’s swim bladder - their air-filled sac that lets them float - is in high demand in China because of its purported medicinal value. Fishermen can get $8,500 for a kilogram of swim bladder. Trade in totoaba is banned by CITES, but still continues. Vaquitas are also caught and drowned in abandoned totoaba nets.

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A vaquita at the water's surface. Photo: NOAA Fisheries/Paula Olsen.

In 2015, in an effort to protect vaquitas, Mexico announced a 2 year ban on gillnet fishing, and that the government would compensate fishermen for their loss. After that failed to slow the decline, a permanent ban on gillnets, except for two species, was added in 2017. In 2019, Mexico announced it would not be compensating fishermen because of the prohibition, leaving many with no choice but to continue fishing with gillnets. Enforcement of the ban has been lax.

In 2017, a committee created to protect vaquita ordered the porpoises taken into a protective sanctuary. 65 scientists from around the world searched for 13 days, and many vaquitas were sighted. Two vaquitas were captured, but the first was released after she did not adapt to captivity well, and the second died because of problems being in human care.

Many organizations are trying to protect the vaquita by creating fishing technologies to use instead of gillnets, and to implement them. Efforts to develop, test, and introduce these devices are well on their way to implementation. This tech works well in shallow water, but not as well in deep water. The goal is for vaquita-safe fishing gear to be available soon.

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Image courtesy of NOAA

Image courtesy of NOAA

A vaquita at the water's surface. Photo: NOAA Fisheries/Paula Olsen.

Fishing boat in Gulf of California. Image courtesy of Gustavo Ybarra / WWF-Canon

Works Cited

Vaquita. (n.d.). Retrieved April 29, 2021, from https://www.worldwildlife.org/species/vaquita

Fisheries, N. (n.d.). Vaquita. Retrieved April 29, 2021, from https://www.fisheries.noaa.gov/species/vaquita

Vaquita. (2021, April 05). Retrieved April 29, 2021, from https://www.mmc.gov/priority-topics/species-of-concern/vaquita/

Cover image courtesy of: Thomas A. Jefferson