Bay Area boaters are being urged by a federal wildlife agency to watch out for and steer clear of gray whales, which are now beginning their annual migration past the Golden Gate to feeding grounds in the Arctic.
Gulf of the Farallones National Marine Sanctuary spokeswoman Mary Jane Schramm said an estimated 18,000 to 19,000 gray whales swim past the Bay Area between March and May each year as they travel from breeding grounds in Baja California to the Arctic.
Schramm said most travel through the marine sanctuary area west of the Bay Area coast, but a few wander into San Francisco Bay and Tomales Bay each year.
The whales, which include mothers with newborn calves, are under stress and "running on near empty" because they get most of their food for the year in the Arctic, Schramm said.
"Even one boat could make a difference" in disturbing a whale to the point that the animal won't complete the journey, or in fatally separating a calf from its mother, Schramm said.
"Please stay your distance and please arm yourself with binoculars so that you can get a good look but can do so without disturbing the animal," Schramm urged boaters.
Schramm said that during the past 10 days, gray whales have been spotted by citizens and ferry boat captains off the Golden Gate entrance to the bay and also within the bay near Sausalito, in the Oakland/Alameda estuary and in Raccoon Strait between Angel Island and Tiburon.
The gray whales are up to 50 feet long and weigh up to 40 tons.
The marine sanctuary spans 1,279 square miles of the Pacific Ocean off the Marin County and San Francisco coasts. It is headquartered in San Francisco and is part of the National Oceanic and Atmospheric Administration.