The exact cause of the death of four Gray's Beaked whales at Papamoa Beach, New zealand remains unknown. Department of Conservation staff are collecting samples to investigate whether the ingestion of oil, toxins and foreign objects from the Rena wreck at Astrolabe Reef could have been a factor in the whale stranding and subsequent death.

The four whales, two lactating females and two young juveniles, were found dead at the eastern end of Papamoa Beach on Saturday, January 21. The cause of the stranding is not yet known, however it appears one of the juveniles stranded first, leading to the subsequent stranding of the others as they stayed nearby. No evidence has been found at this stage to suggest the stranding is related to the Rena, which grounded on Astrolabe Reef about 25kilometres off the coast of Tauranga on October 5. On January 8 a storm broke the ship apart sending more than 150 containers into the water, scattering the beaches with debris and sending more oil into the water. On January 13 Maritime New Zealand confirmed fresh patches of oil had been found on the Papamoa beach east towards Maketu. The amount of fresh oil leaked is unknown, although it is thought to be tens of tonnes.

Gray's Beaked whales are seen off the coast of Tauranga, typically in areas south of Mayor Island and north of Astrolabe Reef and there is a resident Gray's Beaked whale population in the Bay of Plenty, although vert little is known about them. Plans are underway to bury the bodies of the four whales by DOC staff.