SEAWORLD FACT CHECK:

There are only 58 orcas in the current captive population globally. Approximately 13 of these are recent captures from Russia and are not of breeding age. Historically there have only been 230 or so orcas ever held in captivity and most of those died before reaching breeding age or before the first successful birth in captivity (1985)1. Therefore, by definition, the captive population is inbred, because only a small number of breeding-age animals have contributed their genes to the present captive population.

Tilikum has been SeaWorld’s principle stud for the past decade or more and currently at least 11 of his offspring are alive and in the SeaWorld “collection” of 30 orcas2; therefore, again by definition his genes are overrepresented in the captive gene pool.

SeaWorld allowed the mating of a son, Taku (11 years old at the time), with his mother, Katina, in the Florida park. This incestuous mating produced Nalani, who was born in September 2006 and is still alive and living with her mother (who is also her grandmother)3. Taku, her father and brother, was moved to the Texas park and died a year later in 2007.

SeaWorld’s mention of inbreeding in the wild is essentially a non-sequitur. Most inbreeding in the wild is problematic – it incurs a fitness cost and can lead to population decline. This is precisely why it should be avoided in captivity. Pointing out that inbreeding occasionally does occur in the wild is irrelevant to the question of whether it occurs in captivity. Its dangers are the same in either environment.

The reference to the southern resident population of orcas in SeaWorld’s response is ethically very troubling. SeaWorld fails to note that this population is experiencing inbreeding because it went through a catastrophic bottleneck that was anthropogenic in origin (Ford et al. 2011); indeed, it was caused by live-capture operations, commissioned by SeaWorld and other dolphinariums, in the mid- to late 1960s and early 1970s. The population has failed to recover from this depletion due to pollution, damming of rivers leading to salmon declines, and other threats. Despite these endangered orcas being forced to mate within pods due to low numbers of reproductive adults, they do not mate within matrilines (Ford et al. 2011).

In short, the inbreeding seen in this population is the result of its endangered conservation status; it is not normal for orcas. It is a consequence of human impact, initially inflicted by the dolphinarium industry.

References:

Ford, M.J., Hanson, M.B., Hempelmann, J., Ayres, K.L., Emmons, C.K., Schorr, G.S., Baird, R. W., Balcomb, K.C., Wasser, S.K., Parsons, K.M., and Balcomb-Bartok, K. 2011. Inferred paternity and male reproductive success in a killer whale (Orcinus orca) population. Journal of Heredity 102: 537-553.

1 http://www.orcahome.de/orcastat.htm

2 us.whales.org SeaWorld captive orca genealogy map; us.whales.org Tilikum captive orca SeaWorld genealogy map

3 http://www.orcahome.de/swprofiles3.pdf

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SEAWORLD SAYS:

SEAWORLD FACT CHECK:

SeaWorld implies that inbreeding is normal in free-ranging orcas. In its response to this question, it links to an AskSeaWorld post on inbreeding, wherein SeaWorld states that “the Southern Resident killer whales…sometimes mate and breed with members of their own pod,” with no further explanation. However, the southern residents are endangered1– there are only about 85 whales in the entire population and the actual number of reproductive adults is less than 30 (Ford et al. 2011). The observed within-pod mating (there has so far been no within-matriline mating; Ford et al. 2011) is because of the endangered status of this population, not because it is “normal.” SeaWorld does not mention the southern residents’ conservation status – a crucial factor in their inbreeding – in its response.

SeaWorld states that “Taku had become sexually mature at an unexpectedly early age,” implying that this unusual occurrence led to an unintentional but understandable lapse in SeaWorld’s breeding program. It links to an AskSeaWorld post on the definition of “calf” and “adult,” which states that an “adult animal is sexually mature and capable of breeding and calving. In our killer whales this can be as young as 6 for a female and 8 for a male.” Presumably, therefore, Taku would have been 8 or younger when he successfully mated with his mother.

However, Taku was 11 when this incident occurred2. Taku was born in late 1993, he impregnated his mother Katina in early 2005 in the Florida park, Nalani was born in late 2006, and then Taku was shipped to the Texas park, where he died in late 2007, at the age of 14. Therefore, contrary to SeaWorld’s response, the company left a male who was highly likely to be sexually mature in the same enclosure as his mother.

SeaWorld’s response to this question does not actually address the social appropriateness of a son mating with his mother. Even though males remain with their mothers for life in the northeastern Pacific residents, they do not mate with their mothers (Barrett-Lennard 2000), even in the endangered southern resident population (Ford et al. 2011). Unknown behavioral or social mechanisms prevent incest within these free-ranging orca populations. These important mechanisms apparently do not exist in captivity, leading to incest, which SeaWorld claims it “actively avoids” only because it does not “promote genetic diversity” – its social implications are ignored.

SeaWorld ends by saying, “In the past 50+ years of working with killer whales, this example shows how rare [sic] it happens.” The failure of many males to survive to sexual maturity (Jett and Ventre 2015) is a more likely explanation for this rarity than “active avoidance” of incest on the part of SeaWorld.

References:

Barrett-Lennard, L.G. 2000. Population structure and mating patterns of killer whales (Orcinus orca) as revealed by DNA analysis. Ph.D. dissertation from the University of British Columbia, 108 pp.

Ford, M.J., Hanson, M.B., Hempelmann, J., Ayres, K.L., Emmons, C.K., Schorr, G.S., Baird, R. W., Balcomb, K.C., Wasser, S.K., Parsons, K.M., and Balcomb-Bartok, K. 2011. Inferred paternity and male reproductive success in a killer whale (Orcinus orca) population. Journal of Heredity 102: 537-553.

Jett, J. and Ventre, J. 2015. Captive killer whale (Orcinus orca) survival. Marine Mammal Science DOI: 10.1111/mms.12225.

1 http://www.nmfs.noaa.gov/pr/species/mammals/whales/killer-whale.html

2 http://www.orcahome.de/orcadead.htm; http://www.orcahome.de/orcastat.htm

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SEAWORLD SAYS:

In all of our breeding programs, SeaWorld follows zoological best practices and philosophies to ensure the sustainability of a healthy, genetically diverse, and demographically varied population. Breeding is monitored to assure healthy animals and healthy social groups, in line with Association of Zoos and Aquariums (AZA) policy on responsible population management.

It’s important to note that animals in the wild – several different species – do show signs of inbreeding as noted here. Sometimes the inbreeding is extremely widespread, but there is also a genetic price the species pays for such actions. At SeaWorld, we understand these costs and do everything we can to maintain a genetically diverse population with every species, including killer whales. We had one instance with a young male, Taku, living with his mother, Katina. Taku had become sexually mature at an unexpectedly early age. While the calf, Nalani, is alive, healthy and thriving at SeaWorld Orlando, this type of rare close breeding doesn’t promote a genetically diverse population. In the past 50+ years of working with killer whales, this example shows how rare it happens and is something we actively avoid in all our breeding programs.