Effect of repeated harvesting on the growth of Gelidiella acerosa and Gracilaria corticata var corticata occurring at Mandapam coast

The effect of repeated harvesting on the growth of Gelidiella acerosa was studied for one year from August '87 to July '88 and Gracilaria corticata var. corticata for two years from July '87 to May '89. The growth of these agar yielding seaweeds depended on the harvesting season and the interval between successive harvests. The regrowth of these red algae continues as long as the basal rhizomatous portion is intact with the substratum. Hence harvest should be done by pruning the plants leaving the basal portions instead of plucking the whole plants. The commercial exploitation of G. acerosa should be made only during April to July and G. corticata var. corticata during April to June and September to November giving ample interval for their regrowth to harvestable size.