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Column 041017 Wall

Monday, April 10, 2017

Can Dolphins Save Mexico's Vaquita Porpoises from Extinction?

By Allan Wall

An aquatic animal known as the vaquita, which only exists in one small area of Mexico, is on the verge of extinction.  In fact, it may be down to about thirty individuals or less.

Can it still be saved?

The vaquita, which in Spanish means “little cow,” is a type of porpoise endemic to Mexico.  It’s the smallest and rarest type of porpoise.  Its scientific name is Phocoena sinus.  Click here to see what vaquitas look like. 

One curious thing about the vaquita is that the female of the species is larger than the male, which is rare for mammals.  The male is typically 53.1 inches long, while the female is 55.4 inches long.

Not only is the vaquita endemic to the country of Mexico, it is endemic to only one area of Mexico – the lagoons of the Colorado River delta and nearshore areas of the upper Sea of Cortez, also called the Gulf of California. (This body of water, between the Baja California peninsula and the Mexican mainland, is said to be one of the most biologically diverse seas in the world.)  Click here and here to see where vaquitas live.

The vaquita has been known to science only since the 1950s. 

The principal threat to the vaquita is that it gets caught in fishing nets designed to catch marine species that include the valuable totoaba, which is a big fish. The totoaba is also endangered, and too it is endemic to the Gulf of California. (Click here for photo.)

Vaquitas are caught in nets and drowned (as mammals, vaquitas need their oxygen).

The swim bladders of the totoaba are in high demand in China and other parts of Asia, which drives an illegal but lucrative totoaba trade, which even involves Mexican drug cartels.

The Mexican government put a two-year ban on gillnets in the area where vaquitas live, but poaching continues.

In the fall of 2016, it was estimated that there were only 30 vaquitas remaining. For a mammal that is endemic to one area, the quantity of 30 is dangerously low.

The vaquita’s reproductive cycle is still not well-known to scientists.  It is thought that a vaquita reaches reproductive age somewhere between 3 and 6 years of age.  The gestation period is 10 or 11 months long.  Vaquita calves are nursed for approximately 6 to 8 months, and the time between births for a mother vaquita ranges from 1 to 2 years.

If that’s all correct, it means vaquitas are not going to reproduce very quickly, even under ideal circumstances.  And if they keep getting caught in the nets, that makes it even more difficult.

The bottom line – the vaquita is in imminent danger of total extinction.

There have been animals in the past that nearly went extinct, but which survived and thrived.  Two notable examples are the bison and the blue whale.  However, both these animals had much wider ranges than the vaquita.

The Mexican government has announced a last-ditch effort to save the vaquita.  It’s a public/private partnership with international partners.

As described on Nature magazine's website, this effort “… will use dolphins specially trained by the U.S. Navy to corral as many vaquitas as possible so they can be put into protective pens in their natural habitat….”

This plan, of course, is not without challenges.  Vaquitas are not easy to find and travel alone or in pairs.  And, according to Nature, vaquitas “tend to swim away from motorized vessels.”

That’s where the two U.S. Navy-trained dolphins come in.

According to CIRVA member and conservation biologist Barbara Taylor, “The Navy dolphins can easily follow them along like golden retrievers and let us more easily keep track of where the animals are, to let the capture team have their best opportunity to be in the right place at the right time.” Then the vaquitas are to be held in pens to protect them from the gillnets. 

Of course, it’s risky.  Randall Wells of the Chicago Zoological Society puts it this way: “No one has ever tried to catch vaquita to keep them alive. There is so much of this that is being done for the first time. It’s all high risk.” 

But it’s worth a try and might save the vaquita.  It would be a shame for such an animal to completely disappear.

If you would like to donate to the effort to save the vaquita, click here.

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Allan Wall, an educator, resided in Mexico for many years.  His website is located at http://www.allanwall.info.

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