The welfare of bottlenose dolphins and killer whales in captivity

Abstract: The aim of this paper was to investigate whether or not it is possible to keep bottlenose dolphins and killer whales in captivity while maintaining good animal welfare. Today, many zoos and aquariums claim that their primary function is to conserve species and educate people about conservation and threatened species. The keeping of wild animals is justified by conservation programs and by the information spread to the zoo visitors. This does however not seem to be the case for marine mammals such as bottlenose dolphins (Tursiops sp.) and killer whales (Oricnus orca) since these species are not threatened in the wild and neither of them are listed as threatened in IUCN's Red List. Bottlenose dolphins and killer whales are entirely aquatic carnivores and are distributed in all coastal and pelagic waters from the Arctic ice in the north to the Antarctic ice in the south. They are highly social animals that living in complex social structures forming tight bonds to other individuals. Social stressors such as changes within the group, aggression, competition for resources and unstable dominance hierarchies etc, can be very stressful to cetaceans and have a negative impact on their health. It is impossible for animals kept in the same pools to affect their social grouping, being limited to the group that park management has chosen for them, and individuals that would not associate in the wild are forced to do so. Both species have shown self-awareness through mirror self-recognition tests. Animals that are self-aware can learn that different outcomes can be produced or influenced by their behavior and that they have some control over certain parts of their environment. Their self-awareness and examples of tool-use in the wild should mean that a variety of environmental enrichments could be used successfully with these animals to improve their welfare.In 2005 there were at least 199 facilities that kept cetaceans for research or public display. Their enclosures are usually larger than the minimum size requirements but are often made of slick concrete without much variation. Even though more and more parks rely on captive breeding there are still animals being captured from the wild and sold to the display industry. In the whaling season of 2003/ 2004, 78 cetaceans were captured and sold to marine parks by hunters from Taiji, Japan. The live-captures of cetaceans impacts not only the animals being caught, but also the groups they are taken from that have to deal with the loss of a group member. There is little scientific literature on the welfare of bottlenose dolphins and killer whales in captivity and more research should be done on the subject. It is my conclusion that it is very difficult to keep these species and maintain animal welfare at a satisfactory level.