This could be Green Tie, a seal who was entangled in green plastic packing strip back in 2011. He was energetically tussling with other seals in the surf. The scar looks deep, so he is probably not entangled any more.
This blog records my experiences as a docent at the Piedras Blancas Elephant Seal Rookery on Highway 1 in California. Adult seals return to the beach in December for the breeding season.