The following blog series is a point-by-point rebuttal to SeaWorld, following SeaWorld’s critical reaction to the controversial 2013 documentary, Blackfish. Each blog entry will present an argument made by SeaWorld and a rebuttal by Barry MacKay. [teaserbreak]
Lifespans:
While longevity is not necessarily a measure of mental health or physical well-being, the fact is that the best objective indications are that wild orcas live longer than captive ones. It is extremely difficult to measure longevity in wild animals, particularly long-lived and wide-ranging ones, or even to define terms. For example, many long-lived species have very high infant mortality rates, raising the question of whether or not such early mortality should be factored in to estimates of longevity. This is even more so the case for species that reach ages similar to the working careers of biologists, or long enough for the early lives of older individuals to predate technology that may allow direct monitoring. Scientists can ascertain an accurate age estimate by examining a dead orca, but that only provides the age of that individual, and does not allow us to know if it died well before or well after the age normally reached by mature members of the species. The oldest known orca, a wild animal, survived some 80 plus years, and there is good reason to think some have lived more than 90 years—but only in the wild.
The one scientific, relatively long-term study of age structures of wild orcas that does exist (Life History and Population Dynamics of Resident Killer Whales [Orcinus orca] in the Coastal Waters of British Columbia and Washington State, P. F. Olesiuk, M.A. Bigg and G. M. Ellis, Rep. In Commn [Special Issue 12], 1990; see: http://www.freemorgan.org/wp-content/uploads/2012/10/olesiuk_et_al_1990_resiident_orca_bc_wa.pdf) clearly indicates that female orcas in the two orca communities studied had a mean life expectancy of 50.2 years, and typically gave birth for the first time at the just under fifteen years of age. Only one of SeaWorld’s female orcas is, by SeaWorld’s own admission, “close to fifty.”
Males in the study by Olesiuk et al. had a mean life expectancy of 29.2 years, though much older males are known. There really is no comparable study, but ongoing work has underscored its accuracy. Captive orca ages are, of course, known with greater accuracy, and they simply do not live as long as do wild ones. Twenty years ago, some 65 orcas had been caught for the zoo and aquarium industry—but, at this time, only three of them are still alive.
As is true of captive penguins, various respiratory infections seem to be the greatest contributor to early mortality in captive orcas.