Reproductive ecology, of Fucus distichus (Phaeophyceae):an intertidal alga with successful external fertilization

Patterns of natural gamete release and fertilization success are reported for the open-coast macrophyte Fucus distichus L. (formerly Fucus distichus ssp. distichus), which is restricted to tide pools in the upper intertidal zone. The release and settlement of eggs and zygotes of E distichus occurred during daytime low tide periods (DLT), largely on days when the low tide fell between 10:OO and 14:OO h EST; very few gametes were released when high tides fell during the same time interval. Gamete release during nighttime low tides was very low. During the DLT series, gametes were released in all pools and this was better correlated with the time of day than with time of low tide per se.