UPDATE: A pilot whale washed up in Eagle Bay, close to where a mass stranding occurred in the southwest yesterday, and a small pod was seen off the nearby coast.

Department of Biodiversity, Conservation and Attractions staff are about to assess the pod to determine if they are the same whales that were stranded in Toby Bay on Thursday.

The whales were spotted by a plane that flew over the area on Friday morning to monitor the situation.

Almost 30 of the animals died in the mass stranding, in which around 160 long-finned pilot whales had stranded in Toby Inlet, near Dunsborough and Busselton.

Perth Zoo’s DBCA wildlife officers, volunteers and veterinarians worked to save the whales and managed to redirect most of the animals back to the sea; however, 29 died on the ground.

Authorities continued to monitor the harrowing situation on Friday, with an observation plane deployed to fly over deeper waters to check whether the capsule appears to be returning to shore.

About 110 were reported to be about 1.5 kilometers offshore and heading north on Thursday.

Until now, boats deployed by the department had managed to prevent the mammals from being stranded again.

On Thursday afternoon, rescuers had the difficult task of removing some of the carcasses, most of which were adult females, from the shallow waters.

Some threw water on the distressed mammals in an attempt to keep them alive.

DBCA officer Pia Courtis explained that pilot whales were known to run aground along the WA coast and warned that the outcome for them was generally “not good”, explaining that large numbers of them usually died.

He said it was still unclear why the whales had come so far from shore, as is the case with most mass strandings, but they were using some of the things they learned from the Cheynes Beach stranding last year.

More than 50 whales stranded on July 25 and locals reported that the pod had gathered offshore beforehand. Another 40 had to be euthanized.

Courtis also said it was important that dead whales be removed from the beach to prevent others from trying to reach them.

Pilot whales are said to have strong social connections, and this is believed to be a factor in why others in a pod will follow them when one goes to the beach.

Dr Joshua Smith, a marine biologist and senior researcher at Murdoch University, said that while mass strandings are common, researchers have not yet been able to discover exactly why whales become stranded.

“And that’s because each stranding event is relatively unique,” he said. “It is a complex situation. In many cases, this has unique factors, including location, species involved, number of animals, and also the response of the animals in the event of stranding.

“So, for example, in this particular case, my understanding is that there are several relatively large groups that are still out at sea and we have had several individuals that have become stranded on the coast. Unfortunately, we have also had several deaths, which is extremely sad.

“I think the interesting thing about having some of the animals still alive… it’s very encouraging.

“But like I said, they have very strong social groups. So they themselves will be very distressed.

“They will try to stay in relatively small groups to be able to stay together. In terms of how they respond to those who have already run aground, it will be interesting to see how that plays out as the event unfolds.”