Bay scallops prefer eel grass beds and our eel grass beds are being overtaken by invasive seaweeds, polluted by boat fuels, septic overflows and other lovely things and overfishing as well.
If you are lucky enough to find a live scallop you will see its ring of bright blue eyes. Place it in a bucket of water and you will see it "swim" as it propels itself backwards by opening and slamming shut its shell.
Check south side beaches for scallop shells during the winter.
Oh, and don't forget the true locals say "scollup" not "scaaallop."