Doug Coughran, a senior wildlife officer for the Department of Environment and Conservation (DEC), has been involved in rescuing whales for the past 30 years – his exploits have even been the subject of a documentary for ABC television, Whale Patrol.

Unfortunately, not all whales can be rescued, leaving Mr Coughran with the difficult task of euthanising and disposing of the whales, which can weigh more than 40 tonnes.

Mr Coughran said the humpback was discovered in its final stages by tourists at Kennedys Beach, near the Duke of Orleans, on January 12.

After assessing the situation, Mr Coughran made the decision to euthanise the whale.

This is done using a controlled explosive at the back of the whale’s head, which Mr Coughran said would kill the whale within “a nanosecond.”

“After the tourists discovered the whale, local DEC staff attended the scene and confirmed the situation at 11.30pm that night.

“It was ashore in its last stages, and they can take a long time to die. It will be in a state of starvation, while at the same time it is cooking internally from the heat.

“With animals this big it could take them days or even weeks to die. It could still be in the process of dying now,” Mr Coughran said.

“If we are in a position to humanely put down an animal then we will.

“Leaving them alive would be a horrible thing to do. The process is horribly, horribly distressing for the animal and those witnessing it.

Mr Coughran said it was very unusual to find a humpback whale in that location at this time of the year.

“It was very east of normal migration.

“It was very late in the season and it knew it was compromised.”

While whale beachings are commonly reported in the media, Mr Coughran said the unusual phenomena surrounding mass-beachings was usually related to toothed whales.

“In my experience, a humpback whale will usually only beach itself if it is in a terminal condition.

“I suspect what they do is head to shallow waters to avoid predators, but eventually their fuel tanks run dry and the currents and tides push them ashore.”

After euthanising the whale, Mr Coughran said it would be left to break down naturally.

“DEC has signposted the area to warn people, as it could be attracting sharks.”