Investigations of a prehistoric Maya island community on Moho Cay, located near the mouth of the Belize River, Central America, led to discovery of a Middle Classic Period (400--700 A.C.) midden with well preserved animal bone and shell. The midden is described, and recovered animal remains quantified by the total bone or shell weight of each species. Estimates are made of total edible meat weights. The Moho Cay midden data define a subsistence economy based on the exploitation of marine resources and centered on manatee hunting. Artifactual and animal remains indicate that the island Maya had an effective fishing technology for recovery of offshore marine resources. Implications for animal resource exploitation strategies for prehistoric Maya coastal and inland populations are discussed.