The carcass of the sperm whale that was spotted in Nelson's Tasman Bay yesterday was found washed ashore at Rabbit Island today.
Residents in north Nelson reported seeing large whales in the bay yesterday, which were initially thought to be either humpback or right whales.
Otago University zoologist and researcher Liz Slooten said it looked very much like a sperm whale, judging by footage posted on social media.
The carcass of a sperm whale washed up on the beach this morning.
People on the beach said early this morning it appeared that several whales were offshore trying to reach it.
It appeared uninjured, except for the appearance of apparent propellor grazes near its head.
Dr Slooten said the fact that the whale was in such shallow waters - and the way it was behaving - indicated it was unwell and confused.
"It's a bit hard to make out from the short, shaky video clip and you can only see bits of the whale at a time, but it looks like a sperm whale, and that's a very bad place for a sperm whale to be."
Dr Slooten said they were normally found in waters of 1000 metres or deeper - occasionally a few hundred metres - but the location and the behaviour of the whale suggested it was either sick or confused, and probably in the process of stranding.
She said studies of sperm whales since 1990 suggested there were groups that tended to stick to their home territory around Kaikōura, rather than migrate.
Dr Slooten said the video indicated there might have been two whales together, but it was bit hard to see from the video.
Rosemary Cooke was among those who saw the whales yesterday. She has lived at The Glen in north Nelson for 35 years, and while they regularly saw dolphins and orca, she said she had never seen anything like the large whales seen in the bay yesterday.
"We could see out by the corner marker of the Horoirangi marine reserve, some whales breaching and some spouting. It looked at first as if there was one, and then possibly two whales," she said.
Dr Slooten said the video revealed what might have been two whales, but it was hard to tell.
"There's one area where we can see a couple of humps and then another area that looks like the end of the skull, and right towards the front end of the whale there's the blowhole, but it would be great if anyone has better photographs we could see."
She said there were bound to be others in the area to have seen the whale.