About 100 pilot whales have died in a mass stranding on New Zealand’s remote Chatham Islands, officials said on Wednesday.
Most of the animals got stuck on the beach during the weekend, but it was hard to rescue them because the islands are far from mainland New Zealand, about 800 kilometers (500miles).
Biodiversity ranger Jemma Welch from the Department of Conservation (DOC) said 69 whales had already died by the time wildlife officers reached the beach.
She said 28 pilot whales, including two that beached on Monday after the initial stranding, and three bottlenose dolphins were euthanized.
Welch said the animals had to be put down “due to the rough sea conditions and almost certainty of there being great white sharks in the water which are brought in by a stranding like this”.
She said members of the local Maori community had performed a ceremony to honor the spirits of the whales, which would be left to decompose naturally.
Pilot whales grow up to six meters (20 feet) long and are the most common species of whale in New Zealand waters.
Cause of mass stranding
The causes of mass strandings remain unknown despite scientists studying the phenomenon for decades. Some researchers have suggested pilot whales go off track after being attracted by food close to the shoreline, or by following one or two members of the pod that strayed.
Olaf Meynecke, a whale researcher at Australia’s Griffith University, said pilot whales use sophisticated sonar to find prey and for orientation, so some theories link strandings to changes in electromagnetic fields.
“These changes can be caused by solar storms or earthquakes (seismic activities), but there is also a strong connection between active sonar, for example naval sonar, and dolphin strandings including pilot whales,” Meynecke said.
Active sonar, the transmission equipment used on some ships to assist with navigation, is damaging to the health and lives of some marine mammals.