By Mike Madsen
In an already contested article, the Associated Press has posted some original research based upon data from the federal Marine Mammal Inventory Report that indicates annual survival rates for some of the most common marine mammals – including killer whales – at SeaWorld’s three parks are at the top of all North American parks and aquariums.
The AP looked at data from more than five decades and their analysis shows SeaWorld survival rates for bottlenose dolphins and California sea lions actually exceed estimates for those of their wild kin.
According to the data, the survival rate of killer whales born in captivity at SeaWorld parks is almost equal to wild pods; however, the survival rate of all SeaWorld orcas, including those captured from the wild, is lower than estimates of those living in the wild, though survival rates have steadily improved over the past five decades.
The Associated Press 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 were not included in those calculations due to 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. However, 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.
For more information on this topic, please see original article at http://abcnews.go.com/US/wireStory/seaworld-mammals-survive-longer-captivity-24413497