US fisherman dragged overboard by a sea lion as he posed with a fish for a picture

Dan Carlin was waiting for his wife to take a picture when the sea lion pounced

Dan Carlin holding a recently-caught yellowtail at the moment a sea lion leaped up to grab the fish - and him - at Mission Bay in San Diego. (AP)

A fisherman in San Diego was dragged overboard by a huge sea lion as he posed with a fish for a photo on his boat.

Dan Carlin was waiting for his wife Trish to take a picture of him with a large yellowtail fish he had caught that day when the sea lion jumped up and pounced on the hand holding it.

The 62-year-old was forcibly thrown against the boat’s side and dragged six metres underwater by the determined mammal.

Ms Carlin said she told her husband to smile before taking a picture. “So I snap the picture, and I look up and he’s gone,” she told ABC 10. When she looked overboard, all she saw was bubbles in the spot where he had been dragged under the water.

"After 15 seconds, I thought I was going to die," Mr Carlin told The Associated Press. "I continued to struggle, but thought this is the way I was going to die. It was unbelievable to me."

The accountant said he was then suddenly released and swam to the surface, but not before the sea lion took a bite at his foot.

After helping to pull her bleeding husband back on the boat, Ms Carlin steered it to the dock and called for an ambulance. Mr Carlin was hospitalised for two days and needed 20 stitches in his hand. He is still recovering from his injuries three weeks after the event.

“We intentionally don’t feed the seals, we don’t feed the birds, we take the carcasses and all the remains and put them in a bucket,” Ms Carlin said.

“They are very aggressive, and I want parent to know that you should not let your children get within 10 feet of them,” her husband added.