What was initially thought to be the upturned hull of a boat has proved to be a 15-metre long dead whale, floating near d’Urville Island. Sealord skipper Peter Connolly was out fishing when he spotted it off the western side of d’Urville Island north of Nelson on Tuesday. ‘‘It was so bloated it just looked like the hull of a boat upside down . . . when we got close I realised what it was,’’ Connolly said. Connolly said he couldn’t see any obvious injuries to suggest the whale had been hit by anything. ‘‘I’m only guessing from my limited knowledge of whales, but I’m picking just looking at the lines on it, that it possibly could have been a blue whale.’’ Connolly notified the Department of Conservation and posted photos on social media to alert other boat users. DOC communications spokesperson Simon Bayly said as long as the whale was floating they wouldn’t be doing anything, but people should be mindful and report any sightings.