Seasonal changes in growth rate, morphology and alginate content in Undaria pinnatifida at the northern limit in the Sea of Japan (Russia)

The growth, morphology, alginate yield and composition of Undaria pinnatifida was studied from March to August in 2000 and 2001 at the northern limit of distribution of the species in Peter the Great Bay, the Sea of Japan (Russia). The changes in morphology, alginate yield and composition were caused by sporophyte growth and sporulation. The average rate of biomass change was 2-5% d(-1). The highest alginate content (51% d. wt) was obtained from blades, with lower values for sporophylls and midribs. An increase in alginate content was detected before sporulation. The conditions seem favourable for farming the alga in this region, with June the optimum month for harvesting.