Public asked to watch for orphan whale calf

Department of Conservation

RARE MAMMAL: This Gray's beaked whale which beached itself on the Kapiti Coast was pregnant and may have been nursing a calf. The public is being asked to keep an eye for the possible offspring, as it is unlikely to be able to survive on its own.

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The public are being asked to keep an eye out for the calf of a rare Gray's whale found washed up on a Kapiti Coast beach.

The 4.8-metre whale, which was pregnant, beached just south of Whareroa Stream, in Raumati, on Tuesday and died soon afterwards. Conservation Department staff performed an autopsy and Te Papa marine mammal collections manager Anton van Helden found the whale was pregnant with a 20cm foetus.

"It was remarkable to find a little foetus inside her uterus and, surprisingly, it appears she may also have been nursing a calf as there was milk discharging from her mammary gland," he said. The department was asking the public to keep an eye out for any sightings of the calf.

"There is plausibly a baby swimming around out there. It is unlikely the calf will be able to fend for itself without its mother, but it will depend on its age and whether it was weaned."

The whale's head and the foetus have been taken to Te Papa for further study as part of a national project to find out more about the anatomy and skulls of New Zealand's Gray's beaked whale population. The rest of the whale has been buried.

There are 12 known species of beaked whale in New Zealand waters and the Gray's is the most commonly stranded one, with about five to 10 reported strandings a year.

"Although these whales are rare and unusual, we have more strandings of beaked whales than anywhere else in the world," Mr van Helden said.

The autopsy did not reveal any signs of anything grossly wrong. "It is hard to know why she came ashore. She was a beautiful mammal."

Te Papa had the world's largest collection of beaked whales. "They are almost completely unknown from sightings at sea. They are among the most poorly known large mammals on the planet.

"Many of the species we know only from a handful of skeletal remains found on beaches. Having a fresh animal to look at is exciting."

The facial construction of the whale would be studied to better understand how the species used echo location to navigate, he said.

- © Fairfax NZ News