MexicoTed
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Can captive breeding save Mexico's vaquita?
Species don't come much more endangered than the vaquita, a child-sized porpoise that is threatened by fishing nets in the northern reaches of
Mexico's Gulf of California. Just 60 remain, experts warned earlier this year, solidifying Phocoena sinus's status as the world's most endangered
marine mammal. That grim assessment now has researchers pondering a controversial strategy: capturing a handful of vaquitas and breeding them in
captivity.
“Given the crisis we're in, we need to explore all of our options,” says biologist Barbara Taylor of the National Oceanic and Atmospheric
Administration's Southwest Fisheries Science Center in San Diego, California, who serves on the International Committee for the Recovery of the
Vaquita (CIRVA). “Keeping some individuals in a sanctuary is one of those options.”
The idea is fraught with practical and political difficulties. No one has ever tried to capture, transport, or care for the animals. And some
conservationists fear a captive breeding program will undermine efforts to save the species in the wild. “I don't like this idea at all,” says Omar
Vidal, director general of the environmental group World Wildlife Fund (WWF) Mexico in Mexico City. “The risk of killing a vaquita while catching them
is very high. With only 50 or 60 animals left, we can't play with that.”
The population of vaquitas, the world's smallest cetaceans at 1.5 meters long, has been declining by an estimated 34% annually since 2011, almost
entirely because of fishing with gillnets, which entangle and drown the animals. In April 2015, the Mexican government imposed a temporary 2-year ban
on gillnets within the vaquita's range, and on 22 July it made the ban permanent, a move long recommended by CIRVA's scientists. Illegal nets still
pose a threat, however, as poachers pursue a fish called the totoaba, whose bladder fetches up to $20,000 in China. Poachers killed at least three
vaquitas this past March alone.
Given the continuing danger, researchers say they must consider captive breeding. The strategy has helped save the black-footed ferret of the western
prairies and the California condor, whose populations had both dwindled to about 20 animals. But it has never been tried with a cetacean, and although
some small marine mammals, such as bottlenose dolphins, thrive in captivity, porpoises are ill-suited for confinement. “They're very sensitive to
stress and noise, and they have high heart rates,” says Frances Gulland, a CIRVA member and senior scientist at the Marine Mammal Center in Sausalito,
California. “We think of them as the hummingbirds of the marine mammal world.”
In recent years, however, researchers in Denmark, the Netherlands, and elsewhere have shown that some porpoises can be captured and kept in captivity.
Those advances convinced Gulland that it was worth exploring the strategy with the vaquita, and last year she convened an expert team in the
Netherlands to assess the idea's feasibility.
Each phase of the process would pose challenges, the team concluded. Locating the elusive cetaceans in the choppy, murky waters of the gulf is tricky;
the team even suggested exploring the use of trained bottlenose dolphins, such as those kept by the U.S. Navy, to help with the hunt. Once located,
the team envisions herding vaquitas into light-weight surface gillnets, which are safer than conventional nets—a tactic that's been used to place
satellite tags on harbor porpoises in Greenland. Then, they would use a moist stretcher to transport each animal to a soft-sided net pen, and likely
later a large artificial pool, along the gulf's coast. There, they would figure out how to feed and care for the animals, and attempt to persuade them
to breed. The ultimate goal would be to release some parents and offspring back into the wild once the threat of gillnets has been mitigated.
The first vaquita capture could occur in 2017, if further study supports the idea, a recent CIRVA report notes. The likely first target would be a
young male, Gulland says, because a loss in that demographic group would be least harmful to the population if things go awry.
WWF's Vidal fears, however, that the strategy could take the pressure off Mexican authorities to crack down on illegal fishing. “Species need to
recover in the wild,” he adds. Vidal notes that Mexico's Guadalupe fur seal, which was hunted nearly to extinction in the 19th century, has rebounded
without captive breeding.
CIRVA biologists acknowledge the strategy's limitations. “There's no point in putting vaquitas into a sanctuary if they're just going to be killed
once you release them,” Gulland says. But they say capturing a few vaquitas—rather than the entire population, as was done with condors and
ferrets—could provide an insurance policy against extinction.
If history is any guide, they'll have to act fast. In 2006, Taylor was on a team that hoped to capture baiji, an endangered freshwater dolphin that
lived in China's Yangtze River, and relocate the animals to protected lakes. But it was too late: The researchers never found any baiji, and the
species was declared functionally extinct.
http://science.sciencemag.org/content/353/6300/633.full
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DENNIS
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They breed once every two years. 30 females......the natural death rate will quickly surpass the rate of reproduction. Say good bye.
"YOU CAN'T LITTER ALUMINUM"
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sancho
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I was in San Felipe a few weeks ago, Sea Shepard ship just offshore, they are pulling abandoned gill nets. As printed, the
gillnet fishing ban, which was for 2 yrs., has been made permenent. A Mex guy, saying he was an out of work fisherman
came soliciting at the RV park, legit, don't know. The guy was
perplexed as to why the world has gotten envolved and put him
out of work. I learned long ago not to discuss such matters.
The language barrier for 1. Illegal nite fishing is somewhat common, with the Mex Navy enforcing. Would not want
to walk down the malecon with a Sea Shepard shirt on
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shari
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Mood: there is no reality except the one contained within us "Herman Hesse"
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Interesting article that addressed some of my worries such as the difficulty with the capture and not knowing if they can survive in captivity.
Sounds like they have better technology to do this now.
When the idea of trying to save the endangered Pronghorn Antelope was launched...we were told that a species couldn't survive with less than a 100
animals so this makes me think it might be worth a try with a few of the remaining vaquitas...seeing as how they may well be doomed anyway.
The Pronghorn project has been a resounding success with several hundred having been released into the wild.
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