The spinner shark jumped out of the water, propelling itself into the air — joyously, surely — and before you could say “Look at that,” it did it again. While this Canadian jaw drops, the locals on the beach barely look up. The small spinner sharks don’t worry anyone here too much. A surfer ignores the half-hour “no swim order” after it’s spotted and runs back in after a few minutes: “The waves are too good,” he says, flipping his long bangs as he heads into the water off Hutchinson Island. This 50-kilometre strip of Florida along the Atlantic — from Sebastian down to Stuart — is called the Treasure Coast, for the silver and gold left in the sea after a hurricane wiped out a Spanish fleet in 1715. But that’s not the only bounty here.