MoEF sanctions project to assess the impact of exotic seaweed
-First long term comprehensive study to develop appropriate management plan to protect the affected coral and seagrass areas in Gulf of Mannar and Palk Bay
The exotic seaweed, Kappaphycus alvarezii cultivation in the South Palk Bay has invaded over 2 sq.km coral reef areas in the Mandapam coast of Gulf of Mannar in a period of about 5 years. The impacts are visible as the broken seaweed fragments develops a thick green mat on the corals and kill coral by smothering, shading it from sunlight and abrasion within 6 months of invasion, resulting habitat loss and associated fisheries.
The Forest Department started removal of invaded Kappaphycus from the reef area Gulf of Mannar Marine National Park (GOMMNP) to reduce further impact and stress. However, re-growth of the algae following their removal will also be rapid due to the ability of the algae to re-grow from minute attachment points and also the low palatability of the algae to native herbivorous fishes, and thus pose challenge to conservation managers to protect corals from compounded threats of direct local stress and climate change.
The Union Ministry of Environment and Forests (MoEF) has now first time sanctioned a 3 year project with an outlay of Rs. 24.13 lakhs, starting from 01.09.2013 to study the impact of exotic seaweed, K. alvarezii on corals and associated resources and to suggest management measures in GOMMNP through the Suganthi Devadason Marine Research Institute in Tuticorin. The study is being conducted in association with Tamil Nadu Forest Department.
The study includes detailed survey and identification of K. alvarezii affected coral and seagrass areas in GOMMNP, assessment of invasion and damage including mapping of affected areas. Focused studies like damage to corals and seagrasses beds including damage pattern, duration, species-wise, season-wise, and depth-wise; impact on associated fish species and other biodiversity; 3. impact on abiotic factors in particular nutrient level; and 4. impact of cultivation of K. alvarezii using rafts on the seagrass beds, which is the habitat for endangered dugongs.
The comprehensive study would help to develop appropriate management plan to protect the affected coral and seagrass areas in Gulf of Mannar and Palk Bay, which are the lifeline for over 200,000 artisanal fishers.