How long do captive killer whales survive?
Whales held captive outside the U.S. fare much worse than those in American facilities, a new study suggests. According to the report, killer whales typically live almost three times longer in captivity in the U.S. than in other countries.
The study authors obtained U.S. data from the National Oceanic and Atmospheric Administration’s Marine Mammal Inventory Report, which contains information about each captive whale’s age, time in captivity, date of death, and other details. The team also examined data on whales outside the U.S. from The Orca Project.
The final analysis included 83 killer whales in U.S. facilities and 118 in other countries, recorded from 1961 to 2014. One-third of the animals had been born in captivity, and the rest had been caught in the wild.
Nearly two-thirds of the whale deaths during that time occurred during the first five years of the animal’s captivity, the team reports in Marine Mammal Science. Whales held in the U.S. survived in captivity for a median of 12 years, while those outside the U.S. lived for a median of only about four years. Put another way, the whales in non-U.S. facilities had a “61% higher chance of death on any given day than for those held in U.S. facilities,” the authors write — perhaps because regulations in other countries are looser.
Although captive whale survival has risen over the years, these animals still lag their wild counterparts considerably. The authors note that 62 to 81 percent of wild female killer whales live at least 15 years. In contrast, only 27 percent of the now-dead females in the captive study survived that long. Roughly half of the still-living captive female whales are at least 15 years old.
The research also holds some lessons for managers. Captive-born whales faced a higher risk of dying between two to six and 11 to 12 years old. So managers could try to avoid separating whales from their mothers or transferring the animals to other parks during those times. — Roberta Kwok | 23 April 2015
Source: Jett, J. and J. Ventre. 2015. Captive killer whale (Orcinus orca) survival. Marine Mammal Science doi: 10.1111/mms.12225.
Image © Lars Christensen | Shutterstock
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