Most of the west coast fishing seems to be diving.
One thing about trapping is that it's harder to do illegaly.
To have a lobster pot, you have to bait it and leave it on the bottom for a day. The pot then has to have a visible buoy attached to it floating on the surface so you can find it in your boat and pick up the pot. The buoy is going to be sitting around out there all day. Also, somebody ELSE who is also illegal can simply come by and steal the lobsters from the pot themselves. And since YOU'RE using a pot illegally, you can't exactly contact the game warden to complain about someone stealing lobsters from your illegal lobster pot.
That's ghetto. Maine lobsters are the only way to go.
To have a lobster pot, you have to bait it and leave it on the bottom for a day.
Trap. Lobster trap. Pot is what ya cook 'em in. If you're diving for the damn things you might as well put traps at the bottom, let lobstahs mosey on in, and you don't have to chase 'em around the gosh darned ocean floor all day. You could float your lobstah buoy underwater so it's visible when you're diving.
But the whole idea is just ghetto, illegally trapping lobsters under a bridge; who DOES that?
In the real world (the east coast) illegal trapping is easier, since you can do things like moderately exceeding the trap limit, etc., and it's pretty dang hard for anyone to tell what you're doing unless it's egregious. Still, folks get hauled into court every week for trapping violations, whether for size, number, improper license, whatever.