Dolphins in Captivity Position Statement

 

Sentient, The Veterinary Institute for Animal Ethics, opposes the keeping of dolphins in captivity for entertainment and interactive purposes. We acknowledge that injured dolphins receiving treatment or undergoing rehabilitation may require temporary confinement in appropriate sea pens.

Despite efforts by some dolphinariums, the physical, psychological and social needs of dolphins retained in artificial environments such as tanks and pools cannot be met. Dolphins are highly intelligent and socially interactive animals. The dolphin brain has a complex neocortex, which in humans is an area that is associated with problem solving, self-awareness and emotion processing. Studies have shown that dolphins can mimic sounds and behaviours from humans and understand cues and symbols, as well as devise creative play with objects made available to them[1]. Being self-aware raises the concern that they may recognise the restrictions imposed on them in a captive environment, especially where enrichment is severely inadequate.

In the wild, dolphins experience flexible and dynamic social interactions with many other dolphins. In captivity, the number of dolphins with whom an individual may interact is restricted, thus limiting differing social opportunities. Artificially disrupting social groupings has been shown to exacerbate stress, leading to appetite loss, ulcers and increased susceptibility to disease[2].

Wild dolphins also have the opportunity to swim over long distances and dive to reasonable depths, depending on their main location. Without access to appropriate enrichment, captive dolphins typically exhibit behaviours such as circular, repetitive swimming[1]. Cortisol levels of dolphins in an open captive environment have been shown to be 15 times less than those of dolphins maintained in a closed captive environment[3]. In addition, wild dolphins are able to forage and hunt, behaviours that are thwarted in captivity, where they are primarily hand-fed thawed fish.

We dispute the rationalisation offered by dolphinariums that the keeping of dolphins in captivity has educational and conservation benefits. Dolphin shows are presented primarily to entertain, and observers are not offered any insights into the range of natural behaviours typical of these species in the wild, due to the constraints of limited social groupings, confined space, small number of animals and the impact of passive feeding and medical treatments (such as hormones) on behavior[4]. Given that dolphins are not endangered, it is unnecessary for them to be bred and retained in captivity. In addition, very few, if any, are released into the wild.

There is no justification to continue breeding dolphins in captivity and provision should be made to transfer and rehabilitate dolphins from existing dolphinariums to sea pens to allow eventual release, where appropriate.

 

[1] Clark FE, Davies SL, Madigan AW, Warner AJ & Kuczaj II SA (2013) Cognitive enrichment for bottlenose dolphins (Tursiops truncates): Evaluation of a novel underwater maze device. Zoo Biology, 32:608-619

[2] Waples KA & Gales NJ (2002) Evaluating and minimising social stress in the care of captive bottlenose dolphins (Tursiops aduncus). Zoo Biology, 21:5-26

[3] Ugaz C, Valdez RA, Romano MC & Galindo F (2013) Behavior and salivary cortisol of captive dolphins (Tursiops truncates) kept in open and closed facilities. Journal of Veterinary Behaviour, 8:285-290

[4] Perelberg A, Veit F, van der Woude SE, Donio S & Shashar N (2010) Studying dolphin behaviour in a semi-natural marine enclosure: Couldn't we do it all in the wild? International Journal of Comparative Psychology, 23:625-643