Biodiversity in the seagrass beds of the Gulf of Mannar and ... , Gulf of Mannar/Palk Bay, Tamil Nadu, India © SDMRI/MF India, 2012
The objectives of this project are to:
Seagrass meadows are ecologically sensitive and productive habitats of near-shore environments that host many economically and ecologically important species. The Gulf of Mannar and Palk By coasts in Southeastern India support luxuriant seagrass meadows, and the largest extent of seagrass in the country. Thousands of fisher folk depend on the fishery resources associated with seagrass beds for their livelihoods. Seagrass are also a major food source for the endangered marine mammal, Dugong dugon, as well as other endangered species including marine turtles. However, destructive fishing activities such as the operation of bottom set nets and bottom trawling, as well as the discharge of untreated domestic and industrial sewage, have led to the degradation and destruction of seagrass in Tamil Nadu.
MFF had previously sanctioned a Small Grant Project (SGP) for a period of 18 months, from December 2011 to February 2013, to assess the diversity and distribution of seagrass habitats in the Gulf of Mannar and Palk Bay. The study revealed that in the Gulf of Mannar, approximately 101 sq.km is covered by seagrass beds, with 35.89% of seagrass cover along the 140 km coastline between Pamban and Tuticorin. In Palk Bay, approximately 254 sq.km is covered by seagrass beds, with 44.35% seagrass percentage cover along the 130 km long coastal coastline between Pamban and Athiramapattinam. It was also noted that over 20% of the total seagrass beds were damaged or degraded as a result of anthropogenic impacts, as well as natural factors like strong waves and ocean currents.
Results of surveys on seagrass habitats in the Gulf of Mannar, gathered through MFF SGF projects in India and Sri Lanka, were presented at CBD COP 11, in Hyderabad, India on 16th October 2012. One of the outcomes of this meeting was the recommendation that degraded seagrass habitats be rehabilitated and restored in the Gulf of Mannar seascape.
State Departments of Environment and Forests, and Animal Husbandry, Dairying and Fisheries
Local fishing communities
The outputs of this project are:
Monitoring of the seagrass rehabilitated site was conducted between June 2014 and February 2015. The average survival recorded after 9 months of transplantation was 81.5%, 85.7%, and 78.6%for Thalassia hemprichii, Cymodocea serrulata and Syringodium isoetifolium respectively. Percentage cover in the transplanted quadrats started increasing from June 2014, following the transplantation in February 2014. The percentage cover of seagrasses during June 2014 was 28.7%, 30.45%, and 25.48% respectively for Thalassia hemprichii, Cymodocea serrulata and Syringodium isoetifolium. This gradually increased to 62.78%, 68.44% and 50.44% between June 2014 and February 2015. Seagrass shoot density also increased correspondingly from 18.4 no.m-2, 22.4 no.m-2 and 15.6 no.m-2, to 92.7 no.m-2, 118.6 no.m-2 and 64.5 no.m-2 respectively between June 2014 and February 2015, for Thalassia hemprichii, Cymodocea serrulata and Syringodium isoetifolium respectively. Total shoot density was gradually increased from June 2014 to February 2015 (56.20 to 275.80 no.m-2.
Seagrass can sequester and store far more carbon than terrestrial forests. The plantation and restoration of seagrass will contribute towards climate mitigation commitments in the long-term.
Artisanal fishing has been traditionally conducted in the site where the transplantation took place. Some fishing nets, and strong wave action did damage the new growth of seagrass. However, consultations with the fishermen to reduce the fishing pressure in and around the site have been promising, and SDMRI will continue to work with them to ensure healthy growth of the seagrass
Koswari Island, Gulf of Mannar, Tamil Nadu, India
10th Dec 2013 to 10th Mar 2015
Suganthi Devadason Marine Research Institute: INR 266,250
Dr. J. K. Patterson
Director, Suganthi Devadson Marine Research Institute