Ecological observations on the gorgonian sea fan Eunicella cavolinii'in the Bay of Naples

Abstract

Sea fans Eunicella cavolinii (Gorgonacea) do not grow above 15 m water depth on a vertical wall off the island of Ischia, Italy. There is a 90" change in orientation from parallel to the sea surface above 20 m to perpendicular to the sea surface below that depth. The vertical component of wave motion seems to determine orientation above 20 m, whereas below 20 m sea fans orient, as they do normally, to the horizontal water current. Sea fans were evenly spaced at all depths studied and did not overlap or shade one another. At 20 to 25 m gorgonians are larger in effective area than at 15 to 20 m and exhibit a greater size range.