Study calls for better euthanasia practice at whale strandings to avoid suffering

Tuesday, 22 February 2022

Members of Project Jonah attend to stranded pilot whales on Farewell Spit. (File photo)

A researcher is calling for a more consistent approach to euthanasia for stranded whales and dolphins, after her study revealed current practices could be drawing out suffering.

The Massey University study, which reviewed standard operating procedures for euthanising stranded marine mammals across Australasia, was published in international science journal Marine Policy this week.

Researchers found more detailed guidance and consistency was needed, in both how the decision to end a stranded animal’s life was made, and how it was carried out.

Criteria used to determine when it was time to put an animal down and the methods of performing euthanasia varied across jurisdictions. While shooting was typically the method of choice in New Zealand, whales were sometimes killed with chemicals, or tactically-placed explosives.

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Plimmerton resident Justin Stretch (Ngāti Toa) saw the pod enter the harbour on Sunday afternoon. He'd been helping the team care for baby orca Toa at the Plimmerton Boating Club around the clock since.

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The study also revealed a “significant lack of welfare-relevant parameters” were being collected at euthanasias overall, including how long it took the animal to die.

From left: Lead author Rebecca Boys with Massey University Professor Karen Stockin, and student Emily Palmer during a dolphin autopsy.

The story of baby orca Toa, who stranded near Plimmerton last year, was used as a case study to highlight how standard operating procedures were sometimes not followed due to public sympathy, potentially delaying decisions to euthanise suffering animals.

Chemical euthanasia was suggested for Toa – despite New Zealand having no marine vets able to carry out the practice – over concerns about the public perception of shooting him.

Chemical euthanasia was considered for Toa the orca (pictured), despite New Zealand not having any vets capable of carrying out the procedure. (File photo)

Lead author Rebecca Boys, a PhD student in Massey’s Cetacean Ecology Research Group, said despite the importance of standard operating procedures in making sure euthanasia was consistent and humane, detailed, scientific information was currently lacking.

“This can not only place field officers in complex situations, but may also lead to prolonged suffering for stranded cetaceans.

“We need to ensure criteria informing end-of-life decision-making are objective, science-based and well-defined.”

Project Jonah general manager Daren Grover demonstrates how to care for a stranded dolphin. (File photo)

Department of Conservation (DOC) marine technical adviser Hannah Hendriks said the decision to euthanise stranded marine mammals was usually made in consultation with iwi, and stranding response organisation Project Jonah.

The call was typically made by a DOC incident controller based on a range of factors, and was usually carried out by shooting.

Staff tried to make euthanasia as humane as possible by using a calibre appropriate to the size of the animal.

“Careful consideration is given to the target area. Staff undertaking this unpleasant task are required to be experienced or trained.

“At the time of writing, the euthanasia component of the Department’s Standard Operating Procedure and Guidelines were consistent with international best practice.”

New Zealand was one of five countries with a range of criteria for confirming death, he said, and was one of just two that reported euthanasia statistics to the International Whaling Commission each year.

Welfare parameters, like the rifle and bullets used, number of shots fired, and time until death, were recorded, Hendriks said.

“DOC always seeks to improve our procedures to ensure they are in line with best practice and animal welfare guidance, and there [have] been considerable learnings in the last 10 years or so.”

DOC started incorporating that new information into an updated operating procedure and guidelines last year, she said.

Project Jonah general manager Daren Grover said the current system was not perfect, and any review would benefit animal welfare.

He would generally support more consistent procedures for euthanising marine mammals, he said.

“[But] I wouldn’t want a one-size-fits-all approach. As well as the variance in different species we see, there are big differences in size based on age and sex … that needs to be taken into account.”

Euthanasia is only conducted when there are no alternatives to alleviate the whale’s suffering.

The method used in New Zealand caused near-instant brain death – a quick and humane death, he said.

“We make sure every avenue has been explored, but when that decision is made, we want to end that suffering as soon as possible.”

*CORRECTION: An earlier version of this story included comments DOC said were from Mike Ogle. Those comments were actually from Hannah Hendriks. (Amended February 22, 2022, 8.52pm)