SANTA ROSA, Calif. (AP) - The Coast Guard is asking large ships off the Northern California coast to slow down to almost half their normal speed to avoid collisions with endangered whales feasting on an abundance of krill in the water.
A message being broadcast over marine band radio advises the vessels to approach and exit San Francisco Bay at no more than 10 knots and watch for large whales around two marine sanctuaries.
The Santa Rosa Press-Democrat reports about 20 large ships cross the sanctuaries a day.
The National Oceanic and Atmospheric Administration requested the slowdown after its biologists on the Farallon Islands counted a remarkable concentration of whales off the Farallon Islands late last month.
During a one-hour break on June 27, they counted 33 humpback whales, six blue whales and one fin whale, said Dan Howard, superintendent of the Cordell Bank National Marine Sanctuary, which covers 529 square miles off the Sonoma and Marin County coast.
The next day, they spotted 25 humpbacks, seven blue whales, one fin and one gray whale.
Howard said the whales are feeding on a swarm of krill, a tiny shrimp-like crustacean that's a staple of blue whales' diet.
In mid-June, officials from the Marine Mammal Center in Sausalito helped confirm that a juvenile female humpback whale that washed ashore at Point Reyes National Seashore was killed by ship strike.
The Coast Guard message is scheduled to continue until Friday.