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Killer whales held in captivity live shorter lives than wild whales, according to a new study. This may not be the most surprising scientific finding, but the data adds to the debate over the ethics of keeping captive whales.
Twenty years ago, scientists published a study looking at how well killer whales fare in captivity. They found that before 1995, killer whales in captivity had a 94 percent chance of surviving the next year compared to a 98 percent chance in the wild. Since 2005, that percentage for captive animals has crept up to match the number for wild killer whales.
In this latest paper, published in Marine Mammal Science, the journal of the Society for Marine Mammalogy, researchers found that although captive and wild whales now have the same likelihood of surviving from one year to another, those in tanks haven’t fared as well over the long run. The researchers concluded that only 27 percent of captive killer whales live until they’re 15; in the wild that number is estimated to be around 80 percent.
As the researchers found, not all aquariums are equal. Comparing longevity at American theme parks to similar tourist attractions in Russia and China, the researchers found that killer whales in the United States live roughly eight years longer than the ones held in foreign facilities.
“I just can’t express enough how important this paper is—to have scientifically robust and up-to-date assessments of the data is invaluable,” says Ingrid Visser, a marine biologist from New Zealand’s Orca Research Trust, an advocacy organization, that was not involved in the study.
Doug Demaster, science and research director of the Alaska Fisheries Science Center and co-author of the paper published in 1995, says his data, which he updated in 2013 and presented at that year’s Society for Marine Mammalogy meeting but hasn’t yet published, supports the paper’s findings. “They did a real nice job of adapting one of the medical techniques used for looking at survival,” he says. “Peer reviewed publications are the gold standard in our business, so they get a lot of credit for working this up and getting it published.”
SeaWorld trainers emphasize in their advertising material that killer whales live as long in their facilities as in the wild. But this peer-reviewed study challenges that claim, showing that when taking 30 years of data into consideration, that’s not the case. “There’s something going on in the captive environment—specifically for captive-born whales—that’s notably different than for whales in their natural environment,” says lead author John Jett.
Jett is a visiting researcher at Stetson University in Texas, but he is also a former trainer at SeaWorld. Jett and the other author who worked on the paper—Jeffrey Ventre, a rehabilitation doctor and former chiropractor from Washington State—also both appeared in the 2013 documentary Blackfish, a film critical of theme parks like SeaWorld.
But their analysis, says Todd Robeck, a reproduction biologist for SeaWorld, is “not only inaccurate and misleading, it’s inconsistent.” Using the same data sources, Robeck says he can’t replicate the paper’s results. What’s more, he says, is that the paper’s conclusions on how wild killer whales may survive past certain vulnerable ages don’t jibe with the currently available longevity data.
“I know there’s a fairly large anti-captivity sentiment in a lot of the members of the [Society for Marine Mammalogy], which is fine, but I didn’t think it would spill over into science,” says Robeck. “I assumed it was an objective forum, but I’m questioning that now, which is very disappointing for me from a professional standpoint.”
“My duty as a researcher is to be objective,” says Jett.
“Do I believe captivity is not a good thing for the animals? Absolutely, and I’ll be the first one to tell you that. But anyone who understands the science will read it and immediately they will recognize that I had no agenda.”
The debate over captive whales is a complex one, but what this most recent study could do is help researchers better understand what causes killer whale deaths in captivity, says Jett. The detailed survival curves he and Ventre compiled illustrate at which life stages captive killer whales’ health suffers most.
Separating calves from their mothers, for instance, could increase the chance of the calf dying from stress. Spatial constraints and infections that force caretakers to give killer whales a constant stream of antibiotics could also play a role, he says. Those are factors scientists could investigate further. Hopefully, says Jett, the findings can affect change—or at least better inform decisions.