Gracilaria conferta and its Epiphytes: The Effect of Culture Conditions on Growth

Growth rate experiments for Gracilaria conferta and its four competing main epiphytes were conducted in a growth chamber and on a growth gradient table under various growth conditions. The range of conditions tested was temperature (10-30 °C), irradiance (47-404 μE m −2 s −1 ), salinity (10-50 ppt), pH (7.0-9.0) and green versus white light. The conditions under which the growth of Gracilaria conferta was promoted while that of the epiphytes was limited were formulated as follows: Optimal temperature for Gracilaria conferta (25 °C) was inhibiting for Cladophora pellucida. Optimal irradiance (172 μE m −2 s −1 ) for Gracilaria conferta was inhibitory for Ectocarpus confervoides