Studies on the littoral seaweed epifauna of St Croix Island I Physical and biological features of the littoral zone

The physical and biological features of the littoral zone of St. Croix Island are described as a prelude to studies on the seaweed epifauna. Wave action is the most important physical variable and shore community structure is markedly influenced by the differing degrees of wave action around the Island. Sheltered, moderately exposed, exposed and very exposed littoral communities are distinguished and at three transects the zonation of the macrofauna and the percentage cover of the littoral seaweeds is determined. Seasonal variation, particularly in the seaweed Porphyra capensis, is documented, seaweed cover is related to biomass and energy values for 14 littoral seaweeds are determined.