I personally believe that on some beaches, the 'beach renourishment' thingy killed(smothered or dried out) the larvae. The red tide probably helped also. Digging them then leaving the sand to dry out killing the larvae doesn't help either.
I have found that artificials(fake sandfleas, jigs and flies) often work more better than real sandfleas unless impaled on a jig or kept moving. A Pompano is basically a sight feeder and has to have 'help' in seeing the bait. Sometimes, they will go right past a immobile real sandflea. I also believe they can smell and have chummed them with success. Fishing is a puzzle anyhow. As soon as you think that you've figured out a sure-fire system, the fish will make a fool out of you. That's why they call it fishing, rather than catching. JMHO. C2