California ? Marine biologists said Thursday that they planned to spray two lost, injured whales with fire hoses in the next attempt to force the pair to head back to salt water.

The method has never been tried before, and biologists don’t know how the whales will respond today. If the whales like the spray, crews will try to lure them back to the ocean; if they hate it, they’ll try to force them there.

Biologists planned to spray the whales both above water and underwater from the deck of a boat on the Sacramento River. The approach comes after attempts to lead them back to sea using the sounds of clanging pipes, feeding humpbacks and killer orcas failed.

The mother whale and her calf were last spotted about 70 miles from the ocean, in an area of the Sacramento River.