Marine, intertidal, gravel, partially exposed, eulittoral

Gravel beaches seldom have one uniform grain size; most surveys report some sand mixed in with gravel.  Some partially exposed habitats in the Strait of Juan de Fuca have nearly uniform gravel, and very low biological diversities.  Due to the instability of the substratum, the exposed habitats are relatively unproductive with virtually no plant life, and are occupied solely by mobile burrowing animals or epibenthic forms such as shrimp. Gulls sometimes forage in these habitats, and oystercatchers may nest in high intertidal gravel areas.