A great white shark off San Francisco put on a spectacular show alongside a fishing boat this month - and then munched a big salmon just as an angler was about to bring it aboard.

The episode started when Jim Robertson, captain of the charter boat Outer Limits out of Sausalito, found a school of salmon at the channel buoys eight miles west of Lands End. At 2 p.m., just outside Buoy 2, after hours of steady action, two big salmon were hooked at once, Robertson said, and that was when all hell broke loose.

Joseph Meyers of Daly City, an orthopedic surgeon and longtime salmon angler, was battling a salmon estimated at 20-plus pounds.

"On the side of the boat, we saw this massive splash," Robertson said. "I looked over and saw the fin and shouted to everybody, 'That's a great white!' I knew what it was right off.

"Then the great white came up and made a giant swirl around the fish. You could see his back, his dorsal, his tail. The first pass, he chopped off that big salmon right behind the two front fins. A 20-pounder cut clean.

"I told Joe to keep cranking (his reel), and he was reeling in the half of salmon, and here comes the shark again. He rolled on the surface, threw water everywhere, trying to get what was left of that big salmon. But the shark missed it!"

Meyers then brought in the head of the salmon and held it up to cheers from the others aboard.

"Joe had about 8 pounds of the salmon left on the hook," Robertson said. "The shark got the rest."

On Saturday, another shark tale was broadcast over marine radio, an encounter reported by Rich Fitzpatrick, better known as "Skeet," of the commercial boat Josephine out of San Francisco. Over the radio, Fitzpatrick said he found a fresh, half-eaten sea lion floating at Duxbury off Marin, and when he guided his boat for a closer look, a great white shark returned for the rest.

In his 35-year career, Robertson said, he has seen about a dozen great white sharks, including one last fall off Stinson Beach that he estimated at more than 20 feet long.

"All those people who go to Stinson Beach have no idea," Robertson said.

"To me, it's exciting to see them. I'm in awe. They are not scared of anything. They just have one thing on their mind, and that's to eat."