Terry Norton and Nancy Mettee (Editors). 2020. WIDECAST Technical Report No. 20.
Euthanasia is an undesirable but accepted reality for both the sea turtle rehabilitator and the field biologist who encounters a severely debilitated or terminally injured turtle. It raises practical and ethical issues which must be considered to prevent undue stress and suffering to the turtle and personnel involved.
The term euthanasia derives from the Greek eu, meaning good, and thantos, meaning death. The American Veterinary Medical Association’s Panel on Euthanasia defines a good death as “one that occurs with minimal pain and distress”. The goal of euthanasia is to minimize the suffering of an animal whose condition is terminal. However, before this irrevocable decision is made, there are many factors to be considered.
The purpose of this discussion is to determine the most humane end point for an endangered sea turtle with terminal injury. For a more detailed discussion see page 96 in Marine Turtle Trauma Response Procedures: A Husbandry Manual. PDF
Firstly, the necessity for euthanasia must be determined. This should be established by professionals who are familiar with sea turtles, have assessed the extent of trauma and are knowledgeable about local resources available.
Unless the situation is clearly grave (i.e., removal of 3 or 4 flippers, evisceration, or head trauma where the brain is visible), the decision to euthanize should only be made after consultation with a veterinarian that has considerable reptile (preferably sea turtle specific) experience.
Caution is needed regarding euthanasia as what one may perceive as a terminal condition could be survived by one of these amazing creatures. For example, there is a published and credible report of a congenitally blind female nesting on the beach. This report demonstrates that without vision this hatchling survived, thrived, mated and returned to lay eggs of her own.
There are also reports of two-flippered turtles thriving in the wild and nesting.
Full thickness carapace cuts from boat collisions may also seem like cause for euthanasia. However, as noted on this leatherback, wounds of this type have healed over time. This nesting female was seen in both 2006 (left) and 2008 (right).
Secondly, the method of euthanasia must be established. The goal of any euthanasia is to cause quick or instant loss of consciousness, followed by cardiac and/or respiratory arrest and loss of brain function, resulting in death. There are a variety of considerations that must be taken into account.
Administer an intravenous injection of euthanasia solution (a controlled, commercially prepared cocktail of pentobaritol and phenobarbital) at a dose of 3 ml per 10 lbs (5 kg). Additional dosing may be necessary at 1.5 ml per 5 kg if the turtle is still alive after 30 min. Euthanasia solution may be given via the cervical sinus (jugular vein), sub-carapacial sinus, parietal notch sinus, or any exposed vessel. If the IV route is unavailable, intracoelomic (ICo) may be used; however, the time interval between dosing and death is widely variable. More information on administration routes can be found in the Sample Collection section.
Injection of other agents, such as an over dosage of ketamine, telazol, dexmedetomine, propofol, and others may also be used, but dosages are unavailable. If potassium chloride or magnesium sulfate are used, then the animal must first be anesthetized in order for the procedure to be humane.
Inhalant agents (anesthetics, CO2/CO) are not appropriate as sea turtles can hold their breath for a very long time and survive prolonged periods of anoxia.
Exsanguination is not deemed humane unless the animal is previously anesthetized.
The American Veterinary Medical Association panel on euthanasia considers freezing as an unacceptable and inhumane method for euthanasia in any species.
Cervical dislocation is not feasible due to the integrated articulation of the cervical vertebra.
Decapitation does not destroy the brain, which can continue to function even after prolonged periods of anoxia.
Electrocution and drowning do not consistently result in a rapid, painless death.
This chapter should be cited: Norton, Terry and Nancy Mettee. 2020. Euthanasia, in Terry Norton and Nancy Mettee (Editors), Marine Turtle Trauma Response Procedures: A Veterinary Guide. WIDECAST Technical Report No. 20. https://seaturtleguardian.org/euthanasia Accessed [date].