New Zealand whale strandings linked to ocean warming

James Marshall
December 1, 2018

Only four days ago 145 pilot whales were found beached at Stewart Island, off the coast of the South Island.

The Department of Conservation says up to 90 pilot whales beached themselves late Thursday on the remote Chatham Islands.

DoC said it was notified last evening of the stranding of 80 to 90.

By the time rangers reached the latest group of animals early Friday 50 had died, one remained stranded but alive and the rest had refloated themselves and returned to sea.

The mass stranding means more than 200 whales have died in separate incidents over the past week in the region. All but one were dead.

It is possible that whales sometimes navigate incorrectly while in unfamiliar terrain, says Dave Lundquist, the Department of Conservation's technical advisor for marine species and threats. Sadly, the decision was made to euthanise.

New Zealand's summer, the peak time for whales to beach, begins on Saturday and Stockin said more strandings were likely.

'This is always an bad decision to have to make, ' he said.

DOC notified the local Moriori iwi and Ngāti Mutunga iwi and is working with locals to bury the whales where they stranded.

Marine fire officials work to rescue 2 stranded whales in Florida
Marine fire officials work to rescue 2 stranded whales in Florida

The whales were removed on Friday and buried at the site. Skin and blubber samples have been sent to Massey University to learn more.

A DOC statement said marine mammal strandings were relatively common on New Zealand shores.

Whale strandings are not uncommon in New Zealand, but mass incidents are rare and the cause is rarely clear.

Fifty-one whales have died after becoming stranded in the Chatham Islands. Two pods stranded at the southern end of Mason Bay, approximately 2km apart.

DoC Rakiura operations manager Ren Leppens said half of the whales at Stewart Island had already died by the time they were found and due to the condition of the remaining whales and the remote, hard to access location, the decision was made to euthanise the remainder.

The reason whales and dolphins strand is not fully understood but factors can include sickness, navigational error, geographical features, the presence of predators and extreme weather.

The Department of Conservation responds to an average of 85 strandings per year, but most involve only a single animal.

She also pointed out that species such as pygmy killer whales and sperm whales did not normally beach, unlike pilot whales, which regularly wash up on New Zealand beaches in the summer months.

Other reports by Click Lancashire

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