yeah, I live right near SB, and the fishing there is sketchy at best (for me). When you described hooking into something big, I knew it was a bat. I'd have cut line from the pier. If you like the fight, you can get huge bat rays at Alamitos bay at around that same time of twilight. They will drag you up and down the beach, and once you haul them in, they are indeed quite beautiful. And, are very easy to release. Their mouths are kind of a soft bony mouth. Just watch out for the stinger at the back. Just walk backwards into the water dragging them by the bony "handles" behind their eyes.
58" tip-to-tip, released.
On a related note::
If you had kept that gaffed batray, I've heard you can cut batray wing meat in small circles, and prepare them like "fake" scallops. Anyone ever try that?