Wildlife rangers will Wednesday begin shooting 90 dolphins stranded on a remote Australian beach after attempts to refloat them failed.

The dolphins or false killer whales were found on an isolated beach in northwest Tasmania. About 136 are alive, but authorities say it will be a challenge to refloat them.

Department liaison officer Brendon Clark said the stranding was the first by false killer whales in Tasmania in since 1974. That was a pod of more than 160 whales that landed on a beach near Stanley on the northwest coast. Strandings in Tasmania are usually pilot whales.