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

Protruding bodies,'' such as kelp stems, seagrasses, filiform algae, artificial reefs, and engineered structures, constitute substrata for proliferation of benthic communities of great ecological and economical importance. Unfortunately, very little is known of hydrodynamic aspects 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 larvae 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 flux and low sedimentation rate. The results suggest that hydrodynamic impediments to encounter play a major role in determining the spatial distribution of benthic species on protruding bodies by favoring propagules of species with such adhesive devices.