ORLANDO, Fla. – Since the release of a highly-critical documentary last year, Sea World Parks and Entertainment Inc. has been in the crosshairs of animal rights activists who say its killer whales suffer in captivity. But an analysis of federal data shows that annual survival rates for marine mammals at, Sea World’s three parks are at or near the top of all U.S. parks and aquariums. Sea World’s survival rates for bottlenose dolphins and California sea lions actually exceed estimates for those in the wild.

Killer whales born in captivity at Sea World parks live about as long as their counterparts in the wild, according to an Associated Press analysis of five decades of data from the federal Marine Mammal Inventory Report. However, the life expectancy of all Sea World’s orcas, including those captured in the oceans, is lower than of those living in the wild.

Sea World’s survival rates have steadily improved over the past five decades.

“We do a lot of self-critiquing of who is doing what, how,” said Todd Robeck, vice-president of reproductive research at Sea World Parks and Entertainment Inc., which is the largest holder of marine mammals in the United States. “How are you handling food? How are you handling your moms and calves? What is the medical care?”

Critics say that regardless of survival rates, keeping intelligent marine mammals in captivity is inhumane and detrimental to their well-being.

Last year’s documentary, “Blackfish,” explored what may have driven a killer whale named Tilikum to kill veteran Sea World trainer Dawn Brancheau in 2010. The documentary argued that killer whales in captivity become more aggressive to humans and each other.

Several entertainers, including Wille Nelson, Heart and Trisha Yearwood, pulled out of planned performances at Sea World parks, and opponents have been protesting regularly outside Sea World’s Orlando park, holding signs reading “All animals deserve freedom” and “Sea World: let orcas out of prison.”

“Sea World continues to exploit these complex and very socially interactive animals,” said Bryan Wilson, a co-ordinator for the Animal Rights Foundation of Florida, during a recent protest.

AP calculated survival rates for killer whales, bottlenose dolphins, California sea lions and beluga whales – among the most common marine mammals in captivity – at more than 170 U.S. parks and aquariums. Animals younger than a year old weren’t included because of the difficulty of making comparisons in the wild at that age.

Life expectancy averages were calculated from the survival rates. The analysis revealed:

– The average life expectancy for captive killer whales was almost 28 years, compared to an estimated 47 years for the wild population, using often-cited populations of wild killer whales off British Columbia and Washington state. It was also 28 years for all orcas at Sea World parks, but 46 years for Sea World killer whales born in captivity.

– Captive bottlenose dolphins had an average life expectancy of 24 years, and it was almost 45 years for Sea World dolphins. The average life expectancy in the wild is 25 years, using an often-cited population of bottlenose dolphins off the Sarasota coast.

– California sea lions had an average life expectancy of 20 years at parks and aquariums and more than 31 years at Sea World parks. Estimates in the wild put average life expectancy at more than 17 years.

– The average life expectancy for beluga whales was 19.5 years in captivity, and 24.5 years at Sea World parks. Average life expectancy estimates in the wild ranged widely, from 11.5 years to 62 years.

Medical care for marine mammals at parks and aquariums has improved dramatically over the decades, and that has contributed to improved survival rates.

Decades ago, an evaluation of a marine mammal at a Sea World park might require a pool to be drained for an X-ray or the animal to be restrained. No longer. Through behavioural training, and bribes of herring and salmon, the marine mammals at Sea World parks have learned to give breath, urine and blood samples on cue. Dolphins are trained to keep their heads out of the water so endoscopes can be passed into the stomach for a look. An elaborate laboratory on Sea World grounds allow samples to be evaluated immediately.

On a recent day at Sea World’s Orlando park, killer whales Melia and Kayla slid up on their sides on shallow water platform in a pool and urinated on command into cups held by trainers. In another pool, a pregnant dolphin named Bossa was given an ultrasound.

Days later, pilot whale Freddie was bribed to the side of a pool with fish, and trainer Liz Thomas gently grabbed her tail. Veterinarian Stacy Dirocco, dressed in scrubs, swabbed the tail with alcohol, drew the blood and stuck it in a handful of lab tubes.

“We’re looking for evidence of infection or inflammation. We’re looking at electrolytes, liver values, kidney values, blood sugar,” Dirroco said. “We want to make sure we’re always one step ahead of any health problems so we are routinely monitoring everybody to make sure all is well.”

Critics say improving medical care speaks nothing to the quality of life the marine mammals face confined in pools and tanks when compared to swimming freely in oceans. Over the decades, captive marine mammals have died from seemingly preventable causes: electrical shock, allergic reactions, swallowing foreign objects, stress while being moved, drowning, reactions to vaccines, anorexia and heat stroke.

“At the end of the day, I don’t think you can meet the environmental or social requirements to keep animals, not only alive, but dare I say, happy,” said John Jett, a former Sea World trainer. “The costs seem to outweigh the benefits no matter whatever the benefits may be.”

Critics of keeping marine mammals, especially orcas, in captivity say the marine parks should be doing better than the wild, given the advantages of medical care and as much food as the animals need under human care.

“They’ve gotten as good as they can get at keeping these animals alive and it’s still not as good as nature,” said Naomi Rose, a marine mammal scientist at the Animal Welfare Institute, referring to killer whales, in an email from Slovenia, where she was attending a conference. “It does not look like, given time, they will finally figure it out and be as good as nature (or better, which is really what they should be shooting for).”

Jett said the killer whales grow restless and combative in captivity. They often grind their teeth against concrete barriers and gates, breaking them and causing cavities that become conduits for infections, he said.

Christopher Dold, a vice-president of veterinary services at Sea World, denies that orcas wear down their teeth on barriers.

Infections, specifically pneumonia, were the leading cause of death for all marine mammals in captivity as we they are in the wild. Illnesses associated with infections were responsible in more than a quarter of the deaths in captivity reviewed by the AP.

“The animals are really bored,” said Jett, currently a visiting research professor at Stetson University, who was critical of keeping killer whales in captivity in “Blackfish.” ”These are animals with years of evolutionary history to interact with family and friends and catch their food, and do their thing, and you stick them in a concrete bathtub and that essentially removes all stimulation. But they still have the energy and intellect, and those energies sometimes get put toward self-destructive behaviour.”

Whether the protests and criticism have taken a toll is up for debate. Sea World reported a 13 per cent attendance decrease in the first quarter of the year but blamed the decline on a shift of the Easter holiday into the second quarter that pushed back spring break vacations.

Even as conditions improve in captivity, the marine mammals’ native environment is degrading from human-generated pollution, said Dr. Mike Walsh, co-director of aquatic animal health at the University of Florida’s College of Veterinary Medicine

“People think it’s a Cinderella existence out there, and it’s a great place to be but that’s not the way it works,” Walsh said. “It’s survival out there. It’s not a nice place to be unless you’re at the top of the food chain, and even then you’re affected by changes in your environment.”