(LOS ANGELES) -- The shark that killed a 19-year-old trained lifeguard boogie boarding off the coast of Central California could have mistaken the young man for a seal or sea lion, a shark expert said.
Lucas Ransom was surfing Friday morning between 50 and 100 yards offshore at Surf Beach, which is in Vandenburg Air Force Base, north of Santa Barbara, when the shark reared up out of the waves, pulled him under and bit off his leg, witnesses said.
Because of recent storm weather, the water was murky and the shark could have mistaken Ransom for its normal prey, shark expert Ralph Collier told ABC News.
Ransom, who was a junior at University of California-Santa Barbara, majoring in Chemical Engineering, worked at a Murrieta, Calif., community pool as a lifeguard in 2007 and was honored by the city when he and two other lifeguards saved a young boy's life.
Though officials have not identified the type of shark, witnesses described it as being 14 to 20 feet in length.
As a result of the attack, officials closed three beaches in the area -- Surf, Wall and Minuteman -- for 72 hours.
Last year there were 28 unprovoked shark attacks recorded in the United States, and none were fatal. The last fatal attack occurred in 2008 off the San Diego coast.
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