Distribution of the tropical seaweed crops Eucheuma spp. and Kappaphycus spp. inside and outside of their native range

Abstract

Seaweed aquaculture is a fast-growing industry worldwide and has the potential to change the seascape of coastal regions, including the movement of species outside their native range. Two of the crops with the highest global production are the tropical red algal eucheumatoids, Kappaphycus spp. and Eucheuma denticulatum. Cultivation of these species has become an important source of income for coastal communities especially in many areas in South East Asia and the Western Indian Ocean. Low initial investment and a simple vegetative propagation through cutting fostered a rapid expansion of eucheumatoid cultivation and its introduction in diverse tropical and subtropical countries around the world. Despite the economic importance of eucheumatoid cultivation, its relevance for many coastal communities and its global expansion knowledge on genetic variation between and within cultivars of Eucheuma and Kappaphycus and their wild counterparts is yet limited. Through an international consortium we designed a global sampling campaign of cultivated and non-cultivated eucheumatoids from seaweed farms and natural habitats with focus on South East Asia (the Philippines, Malaysia and Indonesia) and the Western Indian Ocean (Tanzania and Madagascar), as well as specimens from non-native areas including islands in the Pacific (Hawaii, Kiribati, Fiji and Solomon Islands). In this talk, we will give an update of this ongoing project and outline initial results from a new initiative to determine diversity within cultivated eucheumatoid specimens from Tanzania. Our project aims at providing novel knowledge on the genetic resources of eucheumatoids in support of a sustainable seaweed industry.