Marine, intertidal, gravel, semi-protected, eulittoral

Gravel beaches seldom have one uniform grain size; most surveys report some sand mixed in with gravel.  Due to the instability of the substratum, these habitats are relatively unproductive with virtually no plant life, and are occupied solely by mobile burrowing animals or epibenthic forms such as shrimp. Protected habitats with gravel intermixed with sand fall under “mixed-coarse.”