ORLANDO, Fla. (AP) — Since the release of a highly-critical documentary last year, SeaWorld Entertainment has been condemned by animal rights activists distressed over the condition of its killer whales. But annual survival rates for some of the most common marine mammals — including killer whales — at SeaWorld's three parks are near the top of all U.S. parks and aquariums, an analysis of five decades of federal data by The Associated Press showed.

SeaWorld's survival rates for bottlenose dolphins and California sea lions actually exceed estimates for those in the wild.

Breakthroughs in training and medicine that allow the parks' medical staffs to perform far fewer stressful or invasive procedures are partly responsible for those successes, SeaWorld officials said.

Decades ago, an evaluation of a marine mammal at a SeaWorld park might require a pool to be drained for an X-ray or the animal to be restrained. No longer. Through behavioral training, and bribes of herring and salmon, the marine mammals at SeaWorld 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 SeaWorld grounds allows samples to be evaluated immediately.

"We do a lot of self-critiquing of who is doing what, how," said Todd Robeck, vice president of reproductive research at SeaWorld 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?"

Killer whales born in captivity at SeaWorld parks have a survival rate nearly equal to their counterparts in the wild, according to AP's analysis of data from the federal Marine Mammal Inventory Report. However, the survival rate of all SeaWorld's orcas, including those captured in the oceans, is lower than estimates of those living in the wild.

While the survival rates have steadily improved over the past five decades, they don't speak to the quality of life that whales, dolphins and sea lions have at SeaWorld parks. Critics say 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 SeaWorld trainer Dawn Brancheau in 2010. The documentary argued that killer whales in captivity become more aggressive to humans and to each other.

Several entertainers, including Willie Nelson, Heart and Trisha Yearwood, pulled out of planned SeaWorld performances, and opponents have been protesting regularly outside SeaWorld's Orlando park.

"SeaWorld continues to exploit these complex and very socially interactive animals," said Bryan Wilson, a coordinator 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 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. A small change in the survival rates can cause big changes in the average life expectancy estimates. So high and low average life expectancies were also calculated to capture the estimate's possible age range within 95 percent accuracy.

The analysis revealed:

— The average life expectancy for captive killer whales at all U.S. parks was more than 27 years, the same as at SeaWorld, with a high estimate of 49 years and a low estimate of 19 years. When accounting only for orcas born in captivity and not captured, SeaWorld's killer whales had an average life expectancy of 46 years. Populations of killer whales off British Columbia and Washington state that are often used as a benchmark for wild orca populations have an average life expectancy of around 49 years.

— Captive bottlenose dolphins had an average life expectancy of almost 24 years, with a high estimate of 26 years and a low estimate of 22 years. Those at SeaWorld had an average life expectancy of almost 45 years. A population of bottlenose dolphins off the Sarasota coast often used as a benchmark in the wild has an average life expectancy of 25 years.

— Captive California sea lions had an average life expectancy of 20 years, with high and low estimates ranging from 21 to 19 years. But those at SeaWorld had a life expectancy average of more than 32 years. 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, with the high and low estimates ranging from 29 to 15 years. It was 24 years at SeaWorld parks. Average life expectancy estimates in the wild ranged widely, from 11.5 years to 62 years, depending on the method of calculating age.

On a recent day at SeaWorld's Orlando park, killer whales Melia and Kayla slid up on their sides on a 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."

Critics say improving medical care does not alleviate the poor quality of life marine mammals face when confined to pools and tanks. Over the decades, captive marine mammals at U.S. parks 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 SeaWorld trainer. "The costs seem to outweigh the benefits no matter whatever the benefits may be."

Critics of keeping orcas in captivity say the marine parks should be doing better than the wild, given the advantages of medical care and a ready supply of food.

"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)," said Naomi Rose, a marine mammal scientist at the Animal Welfare Institute in an email, referring to the overall captive orca population.

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.

"The animals are really bored," said Jett, currently a visiting research professor at Stetson University in Florida.

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

Whether the protests and criticism have taken a toll is up for debate. Sea World Entertainment, Inc. reported a 13 percent attendance decrease in the first quarter of the year, but the company said the decline was because the Easter holiday fell in the second quarter this year, pushing back spring break vacations.

Even as conditions improve in captivity, the marine mammals' native oceans are deteriorating because of 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."

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