Little gained from dolphin postmortem

17:00, Apr 29 2010

The postmortem on a dead dolphin found at Northcote Pt in March has now been completed.

The dolphin was found on March 7 and recovered by the Conservation Department.

At the time DOC confirmed it was a common dolphin but could not comment any further until the postmortem was completed at Massey University.

The dolphin had to kept in refrigerated storage at Massey until April 20 because of construction work at the facility.

Massey University marine ecology lecturer Karen Stockin says it was impossible to determine the exact cause of death.

"It was severely decomposed in some sections," she says.

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It made it very difficult to determine external markings that can sometimes point to a cause of death, Dr Stockin says.

The female dolphin was 1.94 metres in length and weighed 57kg which she says is considerably underweight for a common dolphin.

"It was not the healthiest to begin with," she says.

This was reflected in the thickness of its blubber.

However she could confirm that the dolphin was old enough to have borne a calf.

There was no evidence of lactation which means it's unlikely the dolphin had given birth recently.

It's good news the dolphin hasn't left a calf behind, she says.

Dr Stockin says common dolphins regularly strand or wash up in New Zealand waters and they are frequently seen in the Hauraki Gulf.

They use the Gulf throughout the year as a feeding and nursery area.

Although common dolphins appear to be abundant in New Zealand waters, little research into the size of their population has been done.

North Shore Times