Officials with the Greater Farallones National Marine Sanctuary are asking boaters to watch out for gray whales as they migrate along the coast to the Arctic this spring.
The whales travel close to shore, even right outside the Golden Gate, and are susceptible to collisions with boats, sanctuary spokeswoman Mary Jane Schramm said.
“We need to give them their space for their sake and for our own sake,” Schramm said.
A whale could inadvertently surface and tip a small boat over in San Francisco Bay, where the whales sometimes come for a day or two.
Also, avoiding a boat can cost the whales precious energy they need to migrate. Their energy is mostly depleted from their winter breeding in Mexican waters and they’ve had no appreciable time to eat since late fall, Schramm said.
Also, with the shrinking polar ice cap, gray whales have to travel farther to eat, according to Schramm.
About 19,000 gray whales will migrate through Bay Area waters from March to May.
The whales sometimes even travel as close as the surf zone, where waves crash onto the beach. People may believe they are getting stranded, but that’s usually not the case, Schramm said.
They travel into the surf zone to allow their calves to rest and nurse. The sound of the waves allows gray whales to escape killer whales, which use sound to track their prey. The waves act as an acoustic curtain, according to Schramm.
Calves are completely dependent on their mothers during migration.
Boaters should be alert to a gray whale’s exhalation, which looks like a 10- to 15-foot-high puff of smoke. Little of a gray whale is visible from the water’s surface.
Federal guidelines require boaters to avoid approaching within 300 feet of any whale, cutting across a whale’s path, making sudden directional or speed changes and getting between a cow and her calf, which could cause the calf to starve.
The gray whale is no longer an endangered species, but 16 to 17 years ago the population dropped by a third because of a lack of food. The whales also used to be hunted like many other whales.
“We should just be delighted they’re here,” Schramm said.