It was a whale of a weekend for travelers on the Clinton-Mukilteo ferry.

As many as 20 orcas were spotted close to the Mukilteo ferry dock at mid-afternoon on Saturday, said Howard Garrett of Orca Network, a marine mammal monitoring organization based in Greenbank.

“They were right in there close to shore,” he said Monday. “I guess they were looking for food.”

Bernice Tannenbaum, who described herself as an environmental scientist, gave a vivid description to Orca Network’s spotting report of her sighting off Mukilteo shortly after 3 p.m. She said she counted eight whales, including two adult males a short distance offshore.

“They were close enough to the shore that I could hear them exhale,” she said.

At one point, the whales surrounded a ferry as it traveled between Clinton and Mukilteo, providing a rare glimpse for everyone aboard, Garrett said Monday.

Alisa Brooks of Edmonds tracked the orcas’ progress past Mukilteo from 12:30 to about 5 p.m. on Saturday, and took pictures of the spectacle. Her 2:50 p.m. report to Orca Network read: “They just passed right in front of Mukilteo ferry landing. Whoo hoo!”

Garrett said regular orca sightings in the region have been reported since Wednesday in the Tacoma-Vashon Island vicinity. The whales are believed to be members of Southern Resident J and K pods, based primarily around the San Juan Islands.

He said J pod has 28 members, and K pod 18 of all ages, from adults to youngsters.

Garrett said the pods typically summer around the San Juan Islands, and tend to disappear in winter, with only brief appearances around Whidbey. He said the whales usually spend this time of year near the Continental Shelf, roughly 20 or 30 miles off the coasts of Washington and Oregon.

“They usually never stay more than 24 hours when they show up here,” Garrett said. “But it’s been six days straight — that’s unusual.”

Late last week they were spotted off Vashon Island. By early Saturday morning, reports were coming in of sightings off Langley in Saratoga Passage, off Possession Point, in Possession Sound, near Cultus Bay, and between Point No Point, off the north Kitsap Peninsula and Double Bluff and southwest Whidbey.

On Sunday, a group of orcas swam straight into Elliott Bay in Seattle, Garrett said.

“They were right under the Space Needle,” Garrett said. “They were headed east into the city at sunset. It was their grand finale.”

About noon on Monday, orcas were spotted off Greenbank, he said, and later six were seen headed south around Fox Spit.

Garrett said food is probably the motivating force dictating recent behavior. He speculated that there was either a shortage of salmon farther offshore, or that there was an abundance of blackmouth salmon in Puget Sound.

On the other hand, Orca Network’s hydrophone stationed at Port Townsend has so far picked up no orca calls — “another indication that they’re still down here somewhere.”

In any case, it was quite a show during the weekend, but some observers were a little too enthusiastic, Garrett said.

He said there were several reports of boaters getting too close to the whales near Mukilteo and points southwest around Whidbey. He reminded that the law requires boaters to stay at least 100 yards away.

Meanwhile, to report a whale sighting or other orca activity, call 1-866-ORCANET or e-mail susan@orcanetwork.org.