Animal Spotlight: Vaquita

Taxonomy:

vaquita_illustration_wshepard_352391
William Shephard/WWF
  • Kingdom: Animalia
  • Phylum: Chordata
  • Class: Mammalia
  • Order: Cetartiodactyla
  • Family: Phocoenidae
  • Genus: Phocoena
  • Species: Sinus
  • Average Weight: 120 lbs (55 kg)
  • Average Female Body Length: 4.4 to 4.9 ft (135 to 150 cm)
  • Average Male Body Length: 4.2 to 4.8 ft (128 to 145 cm)
  • Longest Lived: 21 years

Found on one of the most biodiverse places on the planet, the Gulf of California, teems with 891 species of fish and a third of the world’s cetacean species, including the most endangered porpoise named vaquita. Mexico’s only endemic marine mammal, the vaquita is a slender porpoise with distinctive dark rings around the eyes and mouth.

This species has the most limited distribution of any marine cetacean. It is found only in shallow, murky lagoons along the northern end of the Gulf, from Puertecitos, Baja California, north and east to Puerto Penasco, Sonora. Its distribution in the upper part of the Gulf is highly localized, with the highest densities offshore of San Felipe and Rocas Consag as well as offshore of El Golfo de Santa Clara. It is most commonly found around the Colorado River delta.

Very little is known about the vaquita and its biology, only being discovered 60 years ago. Despite the lack of information, it is clear that the vaquita is ‘critically endangered’ due to its limited range and decreasing numbers.

Physical Characteristics:

Known as the smallest porpoise in the world, the vaquita has skin that begins with dark gray on the back fading to a pale gray or white belly. The vaquita has distinctive dark rings around the eyes and mouth with a dark stripe from the chin to the base of the flipper. With newborns, the coloration, particularly the head and area behind the eyes, is much darker.

vaquita
J. Mahannah Concisom

It is similar in size and shape to the harbor porpoise. However, it is more slender and has relatively longer pectoral fins as well as taller dorsal fin in proportion to the body length than in other species of porpoise. The larger fins are thought to increase the surface area of the body to facilitate heat dissipation in the warm Gulf waters.

As a porpoise, the vaquita and its relatives differ from dolphins with their stockier, robust body, lack of an elongated beak, and their distinctively shaped teeth. Porpoises tend to be the thickest near the center with their body beginning to taper down towards the flukes, or the tail. Dolphins have cone-shaped teeth while porpoises have spade-shaped teeth. In addition, a porpoise has a very short beak and fused neck whereas the dolphin has an elongated beak and an unfused neck that allows it to turn its head in multiple directions.

Another significant difference between dolphins and porpoises is that the former is much more talkative than the latter. Dolphins are able to communicate with one another underwater by making whistling sounds through their blowholes. However, scientists are pretty sure that porpoises are incapable of doing the same, possibly due to structural differences in the porpoise’s blowhole.

But the two do have many similarities, one being their extreme intelligence. Both have large, complex brains with a structure in their foreheads, called the melon, with which they can generate sonar, or sound, waves to navigate their underwater world.

Diet:vaquita 3

Vaquitas are reported to feed on a variety of fish, squid, croakers, and crabs. It appears that these porpoises are non-selective, or non-picky, eaters, eating any prey species that are available in the Gulf. All 17 fish species found in vaquita stomachs can be found on demersal and/or benthic zones inhabiting relatively shallow water in the upper Gulf of California. Some of the most common are teleosts, fish with bony skeletons, such as grunts, croakers, and sea trout.

Like their closest relative, the harbor porpoise, they tend to prefer turbid, nutrient-rich coastal waters where their preferred prey are typically found. The shallow coastal waters also protect these marine mammals to avoid attacks from potential predators since they are smaller than other cetaceans.

Like other cetaceans, vaquitas use echolocation to locate their prey. It is also possible that they can also locate their prey by following the sounds of prey movement.

Due to its small size, frequent eating is required to maintain its energy and body heat. Unlike some of the larger cetacean species, the vaquita does not reserve does not have blubber that contains large amounts of energy.

Behavior:

Thought to be primarily solitary, the vaquita is shy and elusive, making it difficult to be observed. Individuals are generally seen to be traveling alone or in small groups of one to three individuals. Although, they are sometimes observed swimming in groups as large as ten. In general though, the vaquita is known to be less social than other cetacean species.

Vaquitas do not engage in acrobatics at the surface of the water, emerging and jumping out of the water. Instead, they rise to breathe with a slow, forward-rolling movement, barely disturbing the water’s surface, and then quickly disappear.

vaquita6_olson_noaa_edited-1024x474
Paula Olson, NOAA

In addition to using echolocation to find food, it also helps them navigate the ocean in areas where light is absent and keep track of other pod members. Vaquitas will use high-pitched sounds to communicate with one another.

They generally seem to feed and swim at a leisurely pace.

Conservation/Threats:

In less than 60 years after the vaquita’s scientific discovery, it quickly made its way up to the top of the endangered species list. In 1996, the International Union of Conservation for Nature declared the porpoise as ‘critically endangered’. And three years prior, the Mexican government created a biosphere reserve of the Upper Gulf of California and Colorado River Delta to protect the vaquita’s only home.

A recent study came out by the International Committee for the Recovery of the Vaquita (CIRVA) estimating that the current population is at around 60 individuals. A sharp decline from 2014 estimated population count of 97 vaquitas and a decline of more than 92% since 1997 when there were 570.

vaquita 2
Uko Gorter

Though not directly hunted, the vaquita still has several threats. The main threat to the survival of the little porpoise is bycatch by gillnet fishing. CIRVA estimated that by 2014, half of the population was killed in gillnets, leaving only 97 left alive in the wild. Gillnet fishing is used to hunt for totoaba, an endangered fish species also endemic to the Gulf, for its swim bladders. Considered as an expensive traditional Chinese delicacy, the bladders can sell for thousands of US dollars in China. Often smuggled over the US border and then shipped to China, its demand is driving the vaquita to extinction. So much so that scientists predict that if harmful fishing practices continue, the vaquita may become extinct by 2022.

In March of 2015, the Mexican government imposed a two-year ban on the use of gillnets and  pledged to invest $36 million each year to support affected fishing communities. The Mexican Navy was also sent to patrol the area to clear any nets found. But, despite President Peña Nieto’s commitment, totoaba fishing increased. Though the number of people jailed for illegal fishing and seizures of totoaba nets grew, efforts to implement more vaquita-safe fishing techniques failed.

Another major threat is habitat destruction, especially since the vaquita is found in only one location. The vaquita’s habitat has been drastically altered ever since the damming of the Colorado River in the United States. Tributaries of the Colorado River drain through the agricultural lands of Southern California and the Mexicali valley, bringing chemical compounds with them. The high levels of organic compounds and chemical fertilizers, which concentrate in the watershed, is related to reproductive incapacity of various marine mammals. Though the levels of contaminants are low based off of eight samples of blubber, liver, heart, and kidneys from vaquitas, the presence of the contaminants could become a potential problem. Over time, there has been a decrease in freshwater input into the upper Gulf of California and potential long-term consequences of this drastic habitat alteration is also a threat to the vaquita’s survival.

Coastal development is also growing uncontrollably, destroying estuaries that are important for the growth of larvae of both non-commercial and commercially important fisheries species.

The dragging of trawl nets to capture shrimp results in the destruction of the seafloor and its ecology. The removal of fauna, in many cases containing juvenile stages of many species of fish, has disturbed the benthic food web. Scientists believe that this effect is drastic since shrimp bycatch outnumbers the amount of shrimp captured and most of the bycatch end up being discarded.

Conservation plans include eliminating bycatch and increasing habitat protection, public awareness and education grams, as well as development of alternative fishing gear and sources of income for local fishing communities.

Interesting Facts:

  • Locally, it’s known as “vaquita marina,” meaning little sea cow in Spanish
  • The term ‘porpoise’ is derived from the Latin ‘porcus’ for pig and ‘piscus’ for fish
  • Its unique black eye rings and lips lead some to call the vaquita the ‘panda of the sea’
  • The vaquita is the only porpoise species that lives in warm waters. Most will inhabit water that is cooler than 58 degrees Fahrenheit or 20 degrees Celsius. However, the vaquita is able to tolerate water that fluctuates from 57 degrees Fahrenheit or 14 degrees Celsius in the winter to 97 degrees Fahrenheit or 36 degrees Celsius
  • It wasn’t until 1958 for the vaquita to be discovered or named when three skulls were found on the beach

References + For More Reading

Vaquita (Phocoena sinus)

WWF: Vaquita

Basic Facts About Vaquitas

Vaquita Life History

IUCN: Phocoena sinus

Save the Vaquita

Aquarium of the Pacific: Vaquita

Arkive: Vaquita (Phocoena sinus)

Porpoise Facts

 

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