SANTA CRUZ (CBS SF) — Well-known Santa Cruz surfer Ben Kelly bled to death after a major artery and vein in his leg were ripped open during a weekend shark attack, the coroner’s office reported Wednesday.

The Santa Cruz Sheriff’s Department said the attack damaged his right knee, severing both blood vessels.

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Shark expert Sean Van Sommeran of the Pelagic Shark Research Foundation attended the autopsy and confirmed that it was a white shark attack.

“I attended the autopsy yesterday, the shark is almost certainly to be subadult white shark estimated to be 10′ plus,” he posted. “Mr. Kelly was on the inside of his friend while surfing on a short board. Kelly was seen by his companion to be pulled underwater amid commotion at Kelly’s board. Kelly surfaced and immediately exited the water with companion however the bleeding could not be stopped.”

Surfing played a vital role in Kelly’s life. He was a respected Santa Cruz area surfboard shaper, married to an avid surfer and was out on the waves whenever he got the chance.

On Saturday afternoon, officials said, the 26-year-old was out surfing in the waters off Manresa State Beach, about five miles west of Watsonville, when he was attacked.

He was brought back to the beach, but died a short time later of his injuries. Kelly was first fatal shark attack victim in Northern California since an abalone diver was killed near Kibeseliah Rock in Mendocino County in 2004.

Social media tributes began rolling into to his Ben Kelly Surfboards Instagram page on Sunday morning as the tight-knit local surfing community plunged into a state of mourning.

“Well brother you reached legend status,” wrote “chejordan28. “We always said if you’re gonna go, go big. We as surfers all understand, that we sign under the dotted line, in invisible ink each time we enter the water. We enter into a place where greater things than us dwell and that it could possibly be the last time we set foot on land.”

“I just want to send my deepest condolences to his mother and family and all our mutual friends in our surfing community here is Santa Cruz. Ben you were one of a kind, one of the good ones, and you will be sorely missed. Aloha bro and much love on your journey to surfing the stars. At least I know you will have a good board under your feet.”

“No words, only grief;” posted nik0hh77. “Yet I have peace and joy knowing Our Father greeted you with open arms. May you rest in Peace my friend.”

Santa Cruz County Sheriff’s personnel were called at about 1:30 p.m. Saturday to the state parks beach, about a mile south of the main parking lot. A man — later identified as Ben Kelly by the coroner — had been attacked by an “unknown shark species,” State Parks said in a news release.

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Following State Parks protocol, the water off of Manresa State Beach one mile south and north of where the surfer was attacked will be closed for five days, reopening Thursday.

A memorial for Kelly with flowers and a broken board were placed in his honor at the beach.

Drone video recorded by Raymond Silver on April 30 about five miles from Saturday’s attack shows a school of sharks ranging from 8 to 12 feet in length.

At this point, it’s unclear what type of shark bit Kelly.

Authorities said there was a narrow escape from a shark in March.

According to the Santa Cruz County Sheriff’s Office the paddle boarder was in the water near 38th Avenue in March when a shark bit the board, “narrowly missing him.”

Fatal shark attacks are rare along the Northern California coast despite it being a major breeding ground for the great white shark. There have been at least two other fatal shark attacks since 1984. Both involved divers.

On Sept. 15, 1985, 28-year-old Omar Conger who was attacked at Pigeon Point while Conger was diving with a friend.

Authorities said Conger was bitten from behind and pulled underwater. His friend was able to pull him to shore, but he died at short time later. It has later determined the shark involved was a 15-16 foot great white shark.

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On August 15, 2004, 50-year-old Randy Fry was killed while diving for abalone near Kibeseliah Rock in Mendocino County. He was diving with a friend at the time. His body was recovered three days later. Authorities determined he had been attacked by a 17-foot great white shark.