Status, exploitation and resource management of alginophytes in India: an account and way forward

Abstract

The biodiversity of Indian seaweeds comprises ca. 865 taxa, of which the alginophytes Sargassum spp., Cystoseira spp. and Turbinaria spp. are traditionally exploited. The alginate trade in India evolved as a cottage industry in the rural coastal regions of Tamil Nadu. The resource surveys have assured sufficient feed-stock availability, but landing data between 1978 and 2019 revealed a 54.85 and 33.59% decline in biomass of Sargassum spp. and Turbinaria spp., respectively. Despite this, alginate production continues to register incremental growth from 112 t in 2004–2005 to 262 t in 2018–2019. The higher production was due to feed-stock imported for domestic processing. Self-reliance in production can only be achieved by resource management and developing a viable farming protocol. This shall support sustainable trade by reducing dependency on wild harvesting. The complete valorisation of biomass by employing a high-throughput integrated bio-refinery protocol for sequential extraction of industrial products, viz. bio-stimulant, pigments, mannitol and alginates, is pivotal for profitable enterprise. Since the domestic industry is heavily depending on artisanal seaweed gatherers of the Gulf of Mannar, it is crucial to protect their rights by resolving issues pertaining to ownership of the resource coupled with conservation and sustainable utilisation. Seemingly, there is still a lot to be done on alginophytes in India. This review provides information and data on various domains of alginate trade aimed at developing a national programme and policy.