While the dioecious brown alga Fucus serratus releases its sexual products in two phases - gametangia at outgoing tide and gametes at incoming tide - the monoecious species Fucus spiralis releases gametangia and gametes with the incoming tide. The monoecious species releases fertilized egg cells; in the dioecious species, the gametes must find each other on the sea floor. Biotope photography, partially with time-lapse.