A necropsy at Charlottetown's Atlantic Veterinary College has been unable to determine why a pygmy sperm whale beached itself and died in Nova Scotia last week.

'The next day it was dead. It was disappointing.' — Eric MacIntosh, Department of Fisheries and Oceans

The whale was found high and dry on a beach in Shelburne Harbour, on Nova Scotia's south shore. Pygmy sperms are amongst the smallest of whales, usually about three metres long fully grown. This was a particularly large one — almost four metres long and weighing more than 200 kilograms.

With the help of members of the Nova Scotia Marine Animal Response Society, fisheries officers rolled the whale back into the water half-a-dozen times. Eric MacIntosh of the Department of Fisheries and Oceans said he was hopeful as he watched the whale gain strength swimming across the harbour.

"In this case we were kind of thinking we had done the right thing and got the whale rescued," said MacIntosh.

"The next day it was dead. It was disappointing."

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The whale was found dead on the shore the day after it was first spotted. (Fisheries and Oceans Canada)

Pygmy sperm whales can be found all over the world, but Nova Scotia is considered to be the extreme north of their range. Tonya Wimmer of the Marine Animal Response Society said her group has only seen five of the whales, some beached and some carcasses, in the last 20 years.

"Being a whale biologist, I automatically think 'Oh my god, I want to see it,' because it's such a rare thing to actually see one of these animals," said Wimmer.

The whale's body was sent to AVC in Charlottetown for a necropsy, but so far it's not revealing any answers. Wimmer said that's often the case with beachings.

"A lot of the times we don't get an answer and, you know, it's left as a puzzle," she said.

Pierre Yves Daoust of AVC said initial examinations are inconclusive.

"We did not identify any significant disease process in any of the organs. We could determine that the animal looked in good body condition, in other words, it did not look thin," he said.

Daoust still has to examine organ tissues under a microscope, but he thinks it is unlikely that will determine the cause of death.