Settlement of germlings in some Japanese Sargassaceae

Professor Takeo Okuda (1929-2005) studied egg release and settlement of germling in Japanese Sargassaceae. Some Sargassum species were found to release eggs at non-periodic intervals, and this finding was different from that in previous studies. Germlings remained on the surface of receptacles for periods of one to eleven days. The period where germlings remained on the surface of receptacles varied with species. Settling velocities ranged from 0.12 to 0.56cm/s, with bigger germlings settling at higher velocities. Germlings of intertidal species attached to the substrate immediately, while those of subtidal species required undisturbed condition for settlement.