The Bay has the largest known seagrass bed in the world. Sea grass beds contain many species from various phyla. Seagrass herbivory is important in the food chain, and eaten by a number of animals, some of them rare. Species that feed on sea grass include green turtles, dugongs, manatees, fish, geese, sea urchins and crabs. The mangrove swamps in the shallow areas are also quite extensive.