The Florida Keys palolo hatch is the strangest tarpon fishery in North America, and much of what anglers think they know about it is wrong. The worms don’t hatch — they disassemble. The full or new moon isn’t the primary trigger — the tide is. And the guides who consistently put clients on fish during the chaos have largely stopped trying to match the hatch, because when the surface is paved with thousands of three-inch naturals, a fly that behaves like one more natural is a fly the tarpon never sees. Here’s what late May in the Keys actually asks of an angler.

An Evening, Not a Date

The folk calendar fixes the event on the May full moon. The guides who have worked it for decades don’t. Bruce Chard, whose long-form accounts remain the most detailed guide-voice description, has argued that the “strength and timing” of current flow matter more than moon phase. In Keys waters, activity can stretch from early May into July, with sequences of four to six consecutive nights under the right conditions. Some May full moons produce nothing. Some cold-fronted June tides produce the event of the year.