ORLANDO — Since the release of a 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 US parks and aquariums, an analysis of five decades of data 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., the largest US holder of marine mammals. ‘‘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 an analysis of data from the federal Marine Mammal Inventory Report. But the survival rate of all SeaWorld’s orcas, including those captured in the oceans, is lower than estimates of those in the wild.
While the survival rates have steadily improved over the past five decades, they do not 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 might have driven a killer whale named Tilikum to kill veteran SeaWorld trainer Dawn Brancheau in 2010. The documentary contended that killer whales in captivity become more aggressive to humans and to one another.
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,’” Bryan Wilson, a coordinator for the Animal Rights Foundation of Florida, said during a protest.
Survival rates for killer whales, bottlenose dolphins, California sea lions, and beluga whales were calculated at more than 170 US parks and aquariums. Animals younger than a year were not included because of the difficulty of making comparisons in the wild at that age.
Life expectancy averages were calculated from 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 US 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, SeaWorld’s killer whales had an average life expectancy of 46 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 has a life expectancy of 25 years.
■ Captive California sea lions had an average life expectancy of 20 years. But those at SeaWorld had a life expectancy of more than 32 years. Estimates in the wild put average life at more than 17 years.
■ The average life expectancy for beluga whales was 19.5 years in captivity. It was 24 years at SeaWorld parks.