A 14-metre whale has died after getting stranded at Golden Bay yesterday.
The enormous animal, believed to be a sei whale, was discovered by locals on Farewell Spit in the afternoon, and the general manager of the whale saving organisation Project Jonah, said it died last night.
Daren Grover said the whale was showing signs of poor health from early on, and there was likely an underlying reason for its stranding.
Grover said Department of Conservation staff and iwi will decide whether to move the whale's carcass, or leave it and place a rahui on the beach.
Sei whale's are described by the Department of Conservation as a rare sight in New Zealand.
At 17 metres long and weighing about 30 tonnes, it's on the "upper end" of size for the species, which is one of the largest types of whales.
About 30 volunteers, local iwi and DOC workers kept it moist and cool last night, after it was found on Farewell Spit.
It didn't appear to be injured, but DOC biodiversity ranger Mike Ogle said it seemed to be unwell with laboured breathing and passed away at about 9.25pm.
"Just as the tide was about to reach it, it did manage to wriggle around, and it managed to roll itself upright - which for a 30 or 40 tonne animal it was quite impressive.
"But then, another 20 minutes later, it took a breath and just didn't take another one," he said.
Ogle said DOC and locals would try to refloat and tow the whale to deeper water this morning, where it could decompose and provide nutrients for local species.
"Tony Nicholls is a local with a fairly powerful 15 metre vessel and he's pulled three sperm whales for us before, with that vessel. So we're hoping we can hook him to this one and he can tow it away as well.
"But the high tides are falling... we've got a lower one than yesterday, so that is not of any benefit at all.
"If we do manage to get it off the tidal flats here, we'll take it halfway up Farewell Spit and tether it to a big anchor up there, well out of the way of everybody, where we've tied large carcasses before."
Mike Ogle said he hasn't seen a stranded Sei whale in 17 years working in the area, and had only seen one at sea.
There is not a lot of museum evidence of the species in New Zealand.
"I've got a message from Rochelle Constantine at the University of Auckland, who curates the DNA tissue archive of stranded beach dead whales. She's only got about four [Sei] samples in that archive, and it's a huge archive so it's very little," he said.
"Anton van Helden who works for DOC in the marine team says there's very little in the museum collections of sei whales in New Zealand."