SEASONAL-VARIATIONS IN AGAR YIELDS AND QUALITY FROM NORTH-CAROLINA AGAROPHYTES

Four species of agar producing seaweed were examined for agar yield and quality on a quarterly basis. Gracilaria blodgettii, Gracilaria tikvahiae and Gelidium pusillum showed only slight seasonal variability in agar yields of both native and alkali modified agars. Of these three, Gracilaria tikvahiae had the lowest agar yields. Gracilariopsis lemanieformis showed strong seasonal variation in agar yields. Agars from all four species had strong seasonal variations in gel strength and these patterns appeared to be species specific rather than related to some common environmental factor. Gracilariopsis lemanieformis produces an unusual native agar which had no detectable gel strength in March and June samples, but produced higher gel strengths (918 and 1245 g cm-2, respectively) after alkali modification. Of these 4 agarophytes, Gracilariopsis lemanieformis, Gracilaria blodgettii and Gelidium pusillum produce agar of commercial quality and should be considered as candidates for aquaculture possibilities.