Click here to see the video of Orca whales off the SF Coast.

FARALLONES ISLAND, CA -- There have been two rare sightings of two separate killer whale pods off the Bay Area coast in the past week.

The gulf of the Farallones National Marine Sanctuary provided pictures of the first sighting on Saturday, about 19 miles outside Golden Gate Bridge. There were about 40 killer whales in that area that feed mostly on salmon. There was another sighting this morning off Half Moon Bay, about seven killer whales were seen attacking a harbor seal.
"To have two such sightings, when we have very few sightings at all of killer whales in the Gulf of the Farallones, is pretty extraordinary," said Jane Schramm from the Gulf of the Farallones National Marine Sanctuary.

That particular pod usually feed in Puget Sound, in Washington state and British Columbia.

The pod of about 40 orcas - which usually stays in the waters off Washington and British Columbia - was spotted last Saturday by a group on an SF Bay Whale Watching boat 19 miles west of the Golden Gate Bridge.

"We were heading back in and all of a sudden the captain shouted 'orca!'" said Fairfax naturalist Trish Mirabella, who was with 50 sightseers. "Then the next thing you know we are surrounded by black dorsal fins. They were jumping out of the water, poking their heads out. It was amazing."

Two newborn calves were also seen among the Farallones group, she said.

"These are resident killer whales," Mirabella said. "They do not migrate; to see them here was rare."

These resident orcas normally feed on salmon, but the fish are scarce, forcing the whales to forage hundreds of miles from traditional feeding grounds, said Mary Jane Schramm, spokeswoman for the Gulf of the Farallones National Marine Sanctuary. She said a researcher in the Northwest, an expert on specific orca pods, identified the Farallones visitors as the L pod, known to inhabit the waters off Washington and British Columbia.

The black-and-white mammals, which can grow up to 30 feet and weigh as much as 12,000 pounds, are the largest species of the dolphin family and are considered highly social and intelligent creatures. They can live to age 50 and beyond. Pods are social groups, often related to one another, Schramm said. Resident killer whales prey on fish and occasionally sharks, and one orca alone can eat up to 500 pounds of food a day.

"They are pack hunters; the cheetahs of the ocean," Schramm said.

Another seven transient killer whales, which travel in small groups instead of a large pod, were seen Friday morning off the Half Moon Bay coast by researchers with the Gulf of the Farallones National Marine Sanctuary.

"They were chasing a harbor seal that took refuge under our research boat until they left the area," Schramm said.

While resident killer whales generally feed only on fish, transients almost exclusively hunt other marine mammals.

"They are probably after the gray whales," said Sausalito resident Vern Bryant, who operates SF Bay Whale Watching. "I see them maybe once a year."

Said Schramm: "It's likely that they are here looking for newborn gray whale calves and trying to separate them from their mothers."

Gray whales are in the midst of their northern migration, which takes them some 10,000 miles each year - the longest of any mammal. The grays migrate from the Bering and Chukchi seas off Siberia and Alaska in the winter to the warmer climate of Baja California, where some give birth.

Now they are migrating back to Alaska and are tired and weak as they make the journey, sometimes swimming 20 hours a day, and they are vulnerable.

"Some of the transient killer whales lie in wait for the gray whales," Schramm said. "They attack not only gray whales, but seals, sea lions, even blue whales."