I realize your newer to this, but we have had that! My contention having done many shark dives and been with hundreds of sharks is they don't know they are being chummed! 400million years has made the apex predator and scavenger of the ocean! But they have very small brains and there is NO evidence they associate man with that activity anymore than the other fish that show up! If it were not the case sharks would show up with just the boat showing up and they don't! We are just bystanders while they do what they do whether it is a kill or a clean up!