Saving Stranded Cetaceans
22 October 2004
Several hundred whales and dolphins get washed up each year in the UK and it is usually the local veterinary practice that has to decide whether or not to try and save the animal. Many are probably already too sick to survive if they are dragged back into the sea and so, for these animals, euthanasia may well be the most humane treatment.
But assessing the vital signs in say, a 30m long sperm whale, is a tricky task. Just because a whale has stopped breathing doesn't necessarily mean it has died as they can hold their breath for long periods - two hours and eighteen minutes is the record for sperm whales. Moreover, the sheer size of many marine mammals and their thick blubber layer make it difficult to reliably check signs like heart rate and body temperature.
"These are very attractive, intelligent animals and so it is understandable that people will want vets to try and get them back in the water at all costs," explained Dr Andy Butterworth, of the university's department of clinical veterinary science. "But even if they are found fairly soon after they have stranded and have not damaged themselves too much, there are often other reasons why they are unlikely to survive. I have seen a lot of stranded dolphins and they are usually old and already very sick. They may have lost all their teeth or they have tumours. In effect, they have come ashore to die".
Dr Butterworth and his colleagues set out to find the information necessary to make a rational decision about the fate of a stranded animal. Before deciding whether its condition is so abnormal that it is unlikely to survive, vets need to have baseline data on what actually is normal. Their study in this week's Veterinary Record (pp 513-518) used measurements taken from healthy captive dolphins and small whales at a marine life centre in San Diego, California. They applied tests of reflexes and other responses used to check vital signs in humans and domesticated animals to see if they are applicable to marine mammals.
The team found that some tests were not suitable for whales and dolphins but a number of others were, and the results were consistent between different individuals and species. The good news is that a full range of tests of consciousness and vitality can be carried out in a few minutes and without the need for specialised equipment.
"There is one very simple test involving splashing a few drops of sea water on the animal's eye to see if it closes its eyelids. Even in those cases that appear to be unconscious there is still a mechanism working to protect the eyes. Using a few straightforward tests like that will help the vet to build up reliable picture of what is happening inside the animal, so you don't need to bring in a lot of expensive probes," says Dr Butterworth.
Notes for Editors:
- 'Evaluation of baseline indices of sensibility in captive cetaceans' by A Butterworth, S C Kestin, JF McBain, The Veterinary Record, October 23, 2004. Drs Butterworth and Kestin can be contacted via the Department of Clinical Veterinary Science, University of Bristol on 0117 928 9280.
- For further information please contact Chrissie Nicholls or Helena Cotton in the BVA Press Office on 020 7636 6541 or email chrissien@bva.co.uk.