Cacapasa,
You're right -- when tarpon gather near a pier, it's a sign that they expect to be fed. (In many locations, fishermen regularly dispose of fish guts by throwing them off a pier -- and tarpon learn quickly.) Similarly, if you are ever on a snorkeling excursion, and schools of sergeant majors swim up to you eagerly until they are touching your swim mask, that's a sign that the excursion organizers feed the fish regularly, in hopes of creating a show for tourists. Dedicated snorkelers abhor the practice.