If gillnets were banned in the upper Gulf of California, the population of the vaquita porpoise would almost certainly recover, say scientists.
Can money and technology be deployed in time to save the vaquita, the planet’s smallest and most critically endangered cetacean? It’s possible, but the clock is ticking for these rare and elusive porpoises of the Gulf of California, whose numbers are dwindling yearly, mostly due to death by drowning in fishing nets.
Last month the Mexican government approved an ambitious plan to require nets that do not snag and kill cetaceans or sea turtles. But the state-of-the-art nets, more expensive and difficult to use than traditional trawl nets and gillnets, will be phased in over three years. Meanwhile, annual deaths among vaquitas, who now number less than 200, were estimated at 40 or more before 2008.
The horrible math does itself.
There is still hope. If enough new nets can be deployed in the first year, significantly reducing vaquita deaths, with even fewer deaths in the second and third years, then perhaps the world can avert yet another ecological tragedy.
Vaquitas were not documented as a species until 1958. They shun human attention and are rarely spotted or photographed, adding to their mystique, but unfortunately leaving them relatively unknown and woefully unsung (compared to, say, orcas), much to their detriment.
Everything about the vaquita (“little cow” in Spanish) is diminutive: There is just one population in the world; they grow less than five feet long; and they stay within a corner of the northern Gulf the size of Los Angeles. With such a small range, their numbers have historically been low, but never this low.
Gillnets used by “artisanal” (small-scale or subsistence) shrimp boats in the upper gulf are particularly lethal for vaquita.
“For whatever reason, the vaquita does not and cannot avoid the nets and is easily entangled. At this point even one or two dying this way a year is far too many,” Dr. Naomi A. Rose, senior scientist at Humane Society International, tells TakePart. “If the gillnets were gone, the vaquita would almost certainly recover. This is one of those horrible situations where the solution to saving a species is simple and obvious and yet is extremely difficult to make happen due to local economic and social factors.”
Those factors are daunting. Most of the shrimping and fishing in the northern Gulf is considered artisanal and is the lifeblood of tens of thousands of families in the region. Remove it, and people will suffer.
Solutions attempted to date are not working.
In 1993, Mexico established a “bioreserve,” with a gillnetting ban, but its boundaries did not cover the vaquitas’ entire range. The collateral slaughter continued. In 2005, a Vaquita Refuge, covering some 80 percent of known habitat, was established and, in 2009, all fishing was banned within the refuge.
But enforcement was lax and efforts to buy back boats and permits had only moderate results. The killing went on.
Now, a presidential commission has called for phasing in small-type trawl shrimp nets that don’t entangle vaquitas, increasing enforcement of the fishing ban within the refuge, and compensating fishermen for lost income during the training and transition period toward 800 new nets, which cost upwards of $1500 each.
Gillnets are indisputably the greatest threats to vaquitas, but other hazards may be blocking their long-term survival.
Lorenzo Rojas-Bracho of the Marine Mammal Program at Mexico’s National Institute of Ecology and one of the world’s leading vaquita conservationists, co-authored a seminal paper, “Conservation of the vaquita,” in 2006, (which was just updated in a paper titled, “Vaquitas and gillnets: Mexico’s ultimate cetacean conservation challenge”).
The authors identified four other “potential risk factors,” including vaquita inbreeding, overfishing of vaquita prey, pesticide pollution and “habitat alteration caused by reduced flow from the Colorado River as a result of dam construction in the United States.”
Since 1960, the river has rarely reached its delta, where it used to feed vast and rich wetlands, once teeming with life. It is now a desiccated place of dried mudfalls.
Rojas-Bracho and coauthors continued: “The ecosystem of the northern Gulf has experienced large-scale stresses from flow-control and flow-reduction of the Colorado River and from many decades of intensive shrimp trawling. There is no reason to believe that these stresses have improved habitat conditions for the vaquita. However, it must also be acknowledged that there is no evidence to suggest that food shortages are affecting the reproductive success or increasing the mortality of vaquitas.”
So far, vaquita prey appears to be stable. But, the researchers warned, “It is important to maintain a precautionary view...Emphasis on the urgent need to reduce the incidental mortality of vaquitas in fishing gear does not imply that habitat degradation (and) large-scale ecosystem-level perturbations should be dismissed as unimportant. Rather, it mainly reflects a difference in documentation and timescale.”
Nets are clearly the “immediate concern,” but river levels and other factors in the river estuary, “are less well characterized and longer term in nature,” the authors wrote.
The decrease of river flow on the upper Gulf has significantly impacted species such as the Colorado Delta clam, shrimp and probably other species as well. The delta, it is believed, can be sustained with fairly low contributions from the Colorado River.
The international politics involved are thorny.
“The Colorado argument is used by politicians as a reason for not taking action,” Rojas Bracho tells TakePart. “All the fishing agencies and coops blame the Colorado,” and its U.S. dams, he says. “There’s always conflict with neighboring countries, but in the past Mexican officials used to say they will not do anything about vaquitas until the river water returns to the Gulf.”
Due to this official inertia, ironically, no studies have demonstrated the actual impact, if any, of lower river levels on the vaquita population.
As for keeping vaquitas away from the deadly gillnets, “This is doable,” says Rose. “The number of nets is already lower than it used to be because of the sanctuary, but any nets are too many, given how low the vaquita’s numbers have fallen.”
There is still the problem of finfish nets. Mexico is starting with shrimpers, but fishermen will also need to transition to gear that doesn’t entangle vaquitas.
“This is something that will require entire communities to change their way of life and livelihood to save a species, and a fairly massive infusion of economic aid,” Rose notes. “There are plenty of good people focused in this situation, and yet still the vaquita declines.”
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