Results of field investigations during two years (2009 and 2010) shows that there are 133 species of marine algae in the sea surrounding Ly Son
and there are up to 45 species with economic values (accounting for about 33.8 percent of the total number of species). The marine algae with economic values can be divided into main groups of food (Asparagopsis taxiformis, Gelidiella acerosa, Ulva latuca...), pharmaceuticals (Asparagopsis taxiformis, Gelidiella acerosa, Gracilaria euchemoides ...), and fertilizer product (the genus Ulva, Chnoospora, Sargassum ...). The major part of the economic marine algae is found in dry season. Natural reserves of economic marine algae at Ly Son Archipelago are estimated as 2310 F. T. (230 D. T.), but on(v a few species are being exploited and used (Gracialaria, Sargassum). The rest is abandoned (Chnoospora spp., Ulva spp.).