The following is a list of marine ecoregions, as defined by the WWF and The Nature Conservancy The WWF/Nature Conservancy scheme groups the individual ecoregions into 12 marine realms, which represent the broad latitudinal divisions of polar, temperate, and tropical seas, with subdivisions based on ocean basins. The marine realms are subdivided into 62 marine provinces, which include one or more of the 232 marine ecoregions. The WWF/Nature Conservancy scheme currently encompasses only coastal and continental shelf areas.