Auckland, New Zealand ? More than 100 pilot whales have beached on New Zealand’s South Island, and at least 19 have died, officials said.

About 100 conservation workers and volunteers rushed to keep the surviving members of the pod covered with moisture, hoping a high tide today will ease the animals’ return to the sea.

Workers had tracked the 123-member pod of whales since it was first seen early Tuesday apparently confused and milling around near the shore.

New Zealand has several mass whale strandings each summer. Whale experts have been unable to explain why the whales swim into dangerously shallow waters.