Grazing effects on the mariculture of the red algae <I>Hypnea musciformis</I> (Rhodophyta, Gigartinales)

Abstract

H. musciformis is the only species utilized so far in Brasil as raw material to the production of k-carrageenan. As natural production is erratic in space and time, different experiments were made to assess the viability of its cultivation in the sea. In this work, the influence of grazing in the mariculture of this species was followed during a 2 year period, by the weight comparison of protected and unprotected inocula. It was showed that, after 15 days experiments, herbivore predation was responsable for great biomass losts, near 100% on the unprotected ones, leading to the inviability of these cultives in most of the year. The use of horizontal nets on rafts to attach the inocula and the choose of culture sites were showed to be successiful ways to prevent the grazing.