Light the grill. Rinse the fish; dry the surfaces and cavities thoroughly. Cut shallow incisions in a crisscross pattern, about 1 inch apart, in each side of both fish.

Season each fish cavity with 1/8 teaspoon of the salt. Put a rosemary sprig in each cavity or rub each with 1/2 teaspoon dried rosemary.

Rub the surface of both fish using 2 tablespoons of the oil, the garlic, the chopped fresh or remaining 1 teaspoon dried rosemary, and the remaining 3/4 teaspoon salt.

Sprinkle the breadcrumbs on both sides of each fish. Drizzle both sides with the remaining tablespoon oil.

Put the fish in a grill basket or onto a very clean grill rack. Cook over moderately high heat for 7 minutes. Turn and grill until golden and just done, about 7 minutes longer. Remove the fish carefully so it doesn't stick.

Serve the fish on a platter. Run a knife between the flesh and the bones and lift off the fillet. Turn the fish over and repeat. Repeat with the other fish. Pass lemon wedges.