Black,-K.P. The relationship of reef hydrodynamics to variations in numbers of planktonic larvae on and around coral reefs. PROCEEDINGS-OF-THE-SIXTH-INTERNATIONAL- CORAL-REEF-SYMPOSIUM,-TOWNSVILLE,-AUSTRALIA,-8th-12th- AUGUST-1988.-VOLUME-2:-CONTRIBUTED-PAPERS-MINI- SYMPOSIUM-1-TO-10-14. Choat,-J.H.;Barnes,- D.;Borowitzka,-M.A.;Coll,-J.C.;Davies,-P.J.;Flood,- P.;Hatcher,-B.G.;Hopley,-D.;et-al.-eds.. 1988. pp. 125- 130. The interaction of wind, tidal and shelf currents with coral reef morphology creates zones that can retain relatively high numbers of planktonic larvae. These zones of low flushing, relative to the current orientations, and the factors which control the variations in larval numbers, have been identified using numerical models of small-scale circulation around a series of schematised reef shapes. The reefs were selected to demonstrate the general principles of larval retention. The results indicate that some regions of any reef have high susceptibility to larval or pollutant retention. Implications of these results are applicable to the management of coral reefs, e.g. control of Acanthaster.