Originally Posted by
surfrob
I think there's a certain tide stage for the structure at the local beach that provides enough water for cover, yet enough sand crabs in that zone, with enough wash to stir them up, to put it all together for active feeding fish (on the open beach).
Around rocks, fish that are there are already actively looking for crabs of all sorts OR for bait fish which are feeding on crabs of all sorts.
This is all my junk science, but it's pretty well backed up by my own experience and discussion with other anglers.