The Bait Ball

Not a place but the event every expedition chases: a sphere of sardines herded to the surface and held there by common dolphins, at which point the ocean's food web arrives all at once. Gannets fold and hit in white columns, copper and dusky sharks rise through the core, seals strafe the edges, and a Bryde's whale may take the whole ball in a single engulfing pass. Swimmers work the perimeter on snorkel — fast, close to the guide, hands to themselves — and drop to scuba only on a stable, long-lived ball. Events last minutes to hours, and no operator can conjure one on demand.

その瞬間のために: The full predation event — dolphins, sharks, gannets, and whales on one sphere of fish

地形: Wherever the predators pin the sardines — open water, no fixed location

流れ（カレント）: The ball itself moves — driven by dolphins from below and wind from above; swimmers reposition constantly.

危険生物・リスク: Feeding sharks and lunging whales in zero-structure open water; positional awareness is the entire safety plan.

保全: The event is natural predation; the ethical duty is simply not to disrupt it — no swimming through the ball, no blocking the dolphins' working lanes.