The U.S. Coast Guard has warned mariners to take care to avoid hitting whales, after three whales were killed off the California coast.

Endangered blue whales, the largest creatures on Earth, have been occasionally sighted along the Orange County, Calif., coastline, The Orange County (Calif.) Register reported.

In the coming weeks, more will be present along the coast, the National Marine Fisheries Service said.

To avoid hitting them, boaters should keep a lookout for the creatures and operate at a safe speed in the Santa Barbara Channel and Los Angeles and Long Beach Harbors, the Coast Guard said.

Authorities asked mariners who strike a whale to report the accident to the National Oceanic and Atmospheric Administration.

Copyright 2007 by United Press International