Four Hector's dolphins have been found dead on South Island Beaches in November.
Department of Conservation aquatic director Elizabeth Heeg says it is too early to say what caused the deaths.
Three of the dolphins were found in the past week. On Saturday, November 27 the body of a dolphin calf was found at Marfells Beach in South Marlborough and reported to DOC the next day. Then on Sunday, November 28 an adult Hector's was found decomposing on a beach just north of Hokitika. A third Hector's dolphin was discovered on November 30 at Ōkārito on the West Coast. This dolphin, also a calf, was quite fresh, indicating it had likely been found and reported not long after it died.
It comes after a calf was discovered dead near the town of Hector, on the West Coast earlier in the month.
Heeg says three of the bodies of the dead dolphins are being sent to Massey University, Palmerston North, for necropsy in an effort to find out how they died.
"From the necropsies done by the Massey team, we can glean really valuable information about these species and the threats they face."
She said DOC is grateful to the members of the public who reported the dead dolphins.
"When people are quick to alert us to discoveries of dead dolphins, however sad, it increases the volume and value of the information we can obtain.
"The people who let us know about these dolphins did exactly the right thing and we're very grateful for that.
"Along with reporting live strandings, the prompt reporting of a dead Hector's dolphin is what we're after from our coastal communities."
She said due to the level of decomposition on two of the bodies, they have been frozen and will be examined later in the month. The third was fresh enough to send chilled and is likely to be examined sooner.
DOC maintains a database of incidents involving Hector's and Māui dolphins, based on reported events. These include live stranded animals, dolphins found dead on beaches, injured at sea, found floating dead in the ocean, or caught as part of recreational or commercial fishing.
Hector's dolphins are one of the world's smallest dolphins. They are mostly found around the coast of the South Island. They are considered nationally vulnerable with their population thought to be around 10,000.
