Fucus species (Phaeophyceae) inhabit intertidal rocky shores in temperate regions. It is a very important primary producer and an ecosystem engineer. The first event in the life history of Fucus is the production of gametes and, subsequently, zygotes by external fertilization, which is influenced by many environmental factors. What are the optimal conditions for Fucus species to spawn? I will elaborate on this and conclude that optimal conditions for the reproductive success of Fucus are to synchronously spawn during the afternoon (Fucus needs to be photosynthetically active) at low tide or slack high tide with calm water conditions (due to the water motion mechanism). Males and females should be in close proximity. Also the high quantity and longevity of gametes, the large egg cells (to increase the target area for sperm) and chemotaxis heighten the reproductive success. It depends on the species if lower temperatures are advantageous – for some species the reproductive success and dispersal is good, but the germling survival is very low at lower temperatures (i.e. during winter or early spring).