FLOW AND FEEDING IN FAN-SHAPED COLONIES OF THE GORGONIAN CORAL, LEPTOGORGIA.

Field studies demonstrate that the gorgonian coral Leptogorgia virgulata assumes a fan-shaped morphology oriented at right angles to prevailing tidal currents. Laboratory studies using a recirculating water tunnel and Artemia salina nauplii as food show that fan-shaped colonies oriented perpendicular to water currents capture more Artemia per unit time than the same colonies oriented parallel to water currents. Several feeding strategies which may operate at various current speeds are suggested. Possible mechanisms controlling feeding response and the selective advantage of colony morphology and orientation as related to feeding and resistance to hydrodynamic forces are discussed.