What is the difference between coastal and littoral?

If an animal is coastal, it means that it lives on or near the coast. 

A ‘coastal zone’ is the area where the ocean water, or sea water, meets the land. It includes sea cliffs, mud flats, and shoreline rocks and ledges. In the ocean, the coastal zone extends to the continental shelf (and the air above it), before the ocean becomes deeper. On land, there are many definitions, such as the low-water line marked officially on a map or the number of kilometres or miles designated by the laws of the country, such as 5-38 kilometres (3-24 miles) inland. Some scientists think that there should not be territorial or boundary limits on the definition of a coastal zone.