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Invasive seaweed in someone's hands
Tamil Nadu, India

Concern for Corals in Indian Marine National Park over Plans to Farm Invasive Seaweed

The government of India is reportedly pushing for large-scale commercial cultivation of an invasive alien seaweed — Kappaphycus alvarezii — inside the eco-sensitive zone of Gulf of Mannar Marine National Park, which is one of the world's richest regions for marine biodiversity and coral reefs.

Gujarat-based Central Salt and Marine Chemicals Research Institute (CSIR-CSMCRI) has identified five locations in the Gulf of Mannar and two locations in Gulf of Kutch for seaweed cultivation and submitted the proposal for NITI Aayog — the National Institution for Transforming India — to initiate pilot-scale cultivation, and has already received funding.

Official sources confirmed to The New Indian Express that the following five locations in Gulf of Mannar have been identified for Kappaphycus cultivation.

  • Pattinamaruthur in Ottapidaram block, Thoothukudi
  • Vellapatti in Ottapidaram block, Thoothukudi
  • Periyasamypuram in Villathikulam block, Thoothukudi
  • Erwadi in Kadaladi block, Ramanathapuram
  • Seeni appadharga in Mandapam block, Ramanathapuram

Sources said the multipurpose seaweed park announced for Tamil Nadu by India’s finance minister Nirmala Sitharaman in the last budget is being used as gateway to push cultivation of exotic species, rather than promoting native seaweed varieties.

Kappaphycus, a fast-growing algae known to absorb high amount of nutrients from seawater is already under rampant cultivation in Palk Bay region. Indigenous to Indonesia and Philippines, the exotic seaweed was introduced to India in 1995 for cultivation. The commercial significance of Kappaphycus lies in its role in production of an industrially lucrative polymer called carrageenan.

underwater coral
Coral reefs of Krusadai island invaded by Kappaphycus / Credit: The New Indian Express. 
  • Watch underwater footage from Krusadai island here.  
aerial view of island
Aerial view of Krusadai island in Mandapam coast in the Gulf of Mannar / Credit: The New Indian Express. 

This is highly problematic considering that the global invasive species database maintained by the International Union for Conservation of Nature (IUCN) placed the Kappaphycus in the 'red list'. The IUCN’s Invasive Species Specialist Group has described Kappaphycus as "destructive invasive species and “a serious danger” to coral reefs.

Numerous scientific studies and research papers published over the years by Suganthi Devadason Marine Research Institute (SDMRI), Thoothukudi and National Institute of Oceanography, Goa hint of possible bio-invasion of corals of Gulf of Mannar islands by Kappaphycus, if left unchecked.

In 2018, a four-year underwater research study by SDMRI, with the funding support of India’s environment ministry, showed that Kappaphycus had invaded Shingle, Kurusadai and Mulli islands in Mandapam cluster and Valai island in Kilakarai of Gulf of Mannar.

Considering the vast impact on corals, the report recommended that the cultivation of exotic seaweed in and around Gulf of Mannar Marine National Park and Marine Biosphere Reserve areas should be completely stopped.

"Government should not grant permission to introduce any alien species in Gulf of Mannar areas including for experimental purposes, as they are capable of altering the ecological balance as well as depleting the health and community structure of key resources like coral reefs and its eco services, and thereby the livelihood of dependent fisher community," the report said.

In fact, there is a 2005 Government Order that restricts cultivation of the exotic seaweed only to the seawaters north of Palk Bay and south of Thoothukudi coast.

Commissioner of Fisheries KS Palanisamy told The New Indian Express that a consultant has been appointed to prepare a detailed project report for the proposed seaweed park. Feasibility studies are being conducted in Thoothukudi, Ramanathapuram, Pudukkottai, Thanjavur, Nagapattinam and Tiruvarur.

Palanisamy distanced himself from CSMCRI efforts to promote Kappaphycus inside the eco-sensitive zone of Gulf of Mannar Marine National Park. "I am not aware of it. We will not promote anything in violation of the 2005 Government Order. Cultivation will be carried out outside the notified area."

Chief Wildlife Warden Shekhar Kumar Niraj told The New Indian Express that: "Kappaphycus is an invasive species and every year the department carries out manual clean-up of coral reefs in the islands invaded by the exotic seaweed.

“We don't have any problem if native seaweed species are cultivated, but at no cost will Kappaphycus be allowed to be cultivated inside the Gulf of Mannar,” he said. “This species can regrow from fragments as small as 0.5 cm making it an extremely difficult to control."

Krishna Chaitanya produced this story with a grant from EJN’s Biodiversity Media Initiative. It was first published by The New Indian Express on 22 December 2021. It has been lightly edited for length and clarity. The Biodiversity Media Initiative is supported by Arcadia — a charitable fund of Peter Baldwin and Lisbet Rausing.

Banner image: Kappaphycus alvarezii in St. Martin's Island / Credit: Md. Simul Bhuyan via Wikimedia Commons