Five sperm whales have been washed up on the shore of the northern Dutch island of Texel, authorities said yesterday.
All of the marine mammals have since perished, they said.
Experts plan to investigate the cause of death of the animals, a spokesman for the economics ministry in The Hague said.
A rescue mission had to be halted during the night owing to bad weather.
The five whales were discovered still alive on Tuesday in the breakwater on the southern tip of the island, which lies between the North Sea and the Wadden Sea.
It was not clear why the whales were in the North Sea, an area they are rarely to be found.
Marine biologists said they would have had very little chance of survival in the shallow water.
The bodies were expected to be retrieved in the next few days.
Dead sperm whales have also been spotted off the German North Sea islands of Wangerooge and Heligoland in recent days.