Fresh, local fish is rare even in So Cal. It may be on the Pacific Rim, but the OC is still on large urban/suburban sprawl with 3.5 million full-time residents, and you will find their seafood options not much different that any other large metropolitan area. The most popular places aren't serving local fish, they serve cod from the Atlantic, salmon from Alaska, mahi-mahi from Mexico, and tons of shellfish and raw bar options from whatever. Fish arrives at commercial distributors already frozen on commercial fishing boats (though, legally, this is still "fresh fish"), and there aren't enough local-caught fish markets/distributors to supply large demand. There are consumer-focused fresh fish markets so the locals can buy can cook their own, but hard to find prepared.
Around DL, Roy's would be my suggestion. But there is Bear Flag Fish Co. which has a few places around Newport Beach, which is part fish market, part restaurant.