where do the abs start?

A couple weeks ago, my friend Il Martello and I did a scouting kayak dive leaving from Muir Beach and paddling maybe 1/2 mile north. We found some rocky outcropping just north of a scenic overlook (we could look way up and see tourists looking down!). Anyway my friend has set crab traps from Muir over the years and wondered why no one ever seemed to be ab diving or spearfishing on that rocky stretch.
We didn't expect great viz and found it to be from maybe 3' to 7'. There actually was tons of good structure especially right along the shore. But we found ZERO abs. And we really looked, way back under rocks, where kelp was attached, everywhere. Even in Monterey and Carmel there are babies back where the otters don't find them, but we didn't see even a single small. And the fish were likewise pretty non-existant.
My question: what's going on here? Why no abs? Does it get too rough in winter or something? How much further north do you have to go before the ab population booms? thanks!

No clue really...I've seen abs at Tomales Point and up by Doran Beach but that is pretty far up from Muir....

 

Sincerely,

Jim

I know a guy who got an Ab by Stinson Beach 20 some years ago