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Column 062915 Wall

Monday, June 29, 2015

Will Mexico's Endemic 'Vaquita' Porpoise become Extinct?

By Allan Wall

The vaquita, an aquatic mammal which only exists in one small area of Mexico, is on the verge of extinction.  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. 

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 Cortes, 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.)  

The vaquita has been known to science only since the 1950s, and it has been declining ever since and is now in danger of extinction.

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, see photos here.

The totoaba is also endangered and is also endemic to the Gulf of California.

The swim bladders of the totoaba are in high demand in China and other parts of Asia.  One totoaba bladder can fetch a price of US$14,000. So that drives an illegal but lucrative totoaba trade that includes poachers and traffickers, and the vaquitas are caught in the nets and drowned (as mammals, vaquitas need their oxygen.)

Even Mexican drug cartels are involved in the totoaba trade.

The bad news is that the total vaquita population, already low, dropped precipitately in one year (from 2013 to 2014) by 42%.  It is now estimated that there are only about 50 vaquitas left.  

For a mammal that is endemic to one area, the quantity of 50 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.  And 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 all this information is correct, that means vaquitas are not going to reproduce that 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 danger of going completely extinct.

There’s an organization called CIRVA, Committee for the Recovery of the Vaquita, which made the estimate of 50.  Vaquitas are not as social as dolphins, they avoid watercraft and are hard to locate.  Therefore, the CIRVA group uses the animal’s acoustic signature (high-pitched sounds used for communication and echolocation) to estimate the population.

The projection now, is that if present trends continue the vaquita will be extinct within three years.  And that would be a shame.

What can be done?

In April of 2015, the Mexican government announced a new program with the goal of protecting both the vaquita and the totoaba.  The use of gillnets has been mostly banned in the area for two years.

A gillnet is a type of netting that forms a wall, and fish catch their heads in it. The problem for vaquitas is that if they get their heads caught in a gillnet and can’t surface when they need oxygen they will drown, as would any mammal.

The program also includes stepped up Mexican Navy patrols to prevent poaching; and financial support for local fishermen who are being affected.

Will such measures work, or is it too late?

There have been animals in the past which 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.

Though the outlook is grim, hopefully the vaquita can be saved from extinction and begin to increase its numbers.

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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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