HYDRODYNAMIC IMPEDIMENTS TO SETTLEMENT OF MARINE PROPAGULES, AND ADHESIVE-FILAMENT SOLUTIONS

Protruding bodies,'' such as kelp stems, seagrasses, filiform algae, a rtificial reefs, and engineered structures, constitute substrata for p roliferation of benthic communities of great ecological and economical importance. Unfortunately, very little is known of hydrodynamic aspec ts of settlement in such habitats. Based on flow-tank experiments and theoretical considerations, we discuss hydrodynamic interference with settlement of larvae on protruding-body habitats. We suggest that larv ae may overcome these interferences by producing mucous threads up to 100 body lengths in size. These adhesive threads enable propagules of suspension feeders to settle in environments of high food-particle flu x and low sedimentation rate. The results suggest that hydrodynamic im pediments to encounter play a major role in determining the spatial di stribution of benthic species on protruding bodies by favoring propagu les of species with such adhesive devices.