Astronomically speaking, fall is here. The autumnal equinox was Sept. 22. Days will be shorter and nights longer until the end of December. This decrease in sunlight hours will cause our waters to cool. This is welcome news to anglers who have been dogged by hot midday temperatures and slow fishing. Migratory baitfish such as sardines and threadfin herring are highly sensitive to water temperature. The slightest hint of cooling in the northern gulf will inspire them to start moving this way. As the bait masses begin to flow into our region, a host of coastal migratory species such as mackerel, cobia, kingfish, bonito and blacktip sharks arrive with them. Expect to start seeing frenzies of fish attacking bait just off our beaches each morning. This increase in baitfish supply, coupled with a host of minnow-munching surface predators get the bottom fish fired up. On a fall dive trip a few years ago we dropped in on a dense swirling tornado of sardines that was holding vertically over a rock pile. A school of kingfish had them surrounded. Periodically the kings would dart into the middle of the bait pod. At that same moment, gag grouper would dash upward from the bottom and strike. This symbiotic teamwork is just one reason that upper column fish and benthic reef dwellers both turn on when bait migration returns. Ed Walker charters out of Tarpon Springs. He can be contacted at email@example.com.