Factors affecting the distribution of the genus Uca (Crustacea: Ocypodidae) on an East African shore

Abstract

Four species of fiddler crab, genus Uca, occur within the marine reserve at Watamu, Kenya. Quantitative sampling reveals that although all species may occur on the same shore, populations of each species remain discrete. The main factors controlling species distribution appear to be height above low water and the type of substratum. A detailed study of feeding appendages and gut structure confirms that each species is adapted to feed on a particular type of sediment.