Coastal Ecosystem Restoration

SDMRI has initiated coastal ecosystem restoration particularly coral reefs and seagrassess restoration and artificial reefs since 1999. SDMRI has successfully restored over 4 sq.km degraded reef area in the Gulf of Mannar using low-tech and low cost transplantation techniques and various artificial substrates (concrete frame and fish houses) and native coral species (branching and massive) with high survival (> 85%) and growth rates. Regular monitoring of restored coral sites in Gulf of Mannar is also in progress.

As a part of degraded habitat restoration and enhancement of biodiversity, artificial modules constructed using ferro cement and fly ash were used and monitoring of artificial reef sites is still going on.

Coastal Ecosystem Monitoring

SDMRI is involved in coastal ecosystem monitoring particularly reef and seagrass ecosystems monitoring in the Gulf of Mannar since 1999. SDMRI has surveyed the entire Gulf of Mannar area to assess the status, diversity, distribution and abundance of corals and seagrasses, health and associated fishery resources. The regular environmental monitoring in 20 sites in Palk Bay and Gulf of Mannar is in progress.

Integrated Coastal & Disaster Management

Studies involving resource Mapping, developing ICZM approach to reduce long term impact of natural hazard; Identification of elements at risk in coastal region and mapping of zones of risk; and listing of mitigation measures and to identify the gaps, are conducted.

Post tsunami environmental impact assessments

SDMRI played lead role immediately after tsunami in informing the country about the status of coral reefs in the Gulf of Mannar Ecosystem. A rapid assessment on the status of corals of Gulf of Mannar was conducted within a week (04-10 January 2005) after tsunami and submitted report to the Union and State Governments.

The Tamilnadu State Department of Environment assigned a project on "Rapid environmental impact assessment of tsunami along Tamil Nadu Coastal areas". In this study, the entire Tamil Nadu coastline, covering 950 km distance was assessed. The tsunami impact on physical, chemical and biological properties in water and sediment in the intertidal, subtidal and coastal landward areas were assessed. The shoreline changes in the tsunami affected coasts were also assessed. The study was completed in 40 days during February-March 2005.

Post tsunami reef ecosystem assessment and monitoring

SDMRI initiated long term regular coral reef monitoring in the Gulf of Mannar after tsunami since January 2005 in order to assess the status of health of the reefs, including coral diseases, and bleaching due to climate change. Annual bleaching during summer is a regular phenomenon in the Gulf of Mannar since 2005. Thus the monitoring helps to know the status of the coastal ecosystem and this is very important component in any viable management mechanisms.

Biodiversity studies

SDMRI is actively involved in the biodiversity studies particularly survey, assessment and identification of marine resources. A field guide for the identification of stony corals from Tuticorin coast was published in 2004. Other field guides on the identification of cephalopods, gastropod and fishes are in the process of preparation.

Coral biology and larval recruitment pattern

Studies involving spawning season, annual spawning cycles and spawning synchrony for different species; Gonadal development and gametocyte; Factors favourable for multi-synchronous spawning; Role of lunar periodicity and the possible physical stimuli for spawning; and Larval recruitment pattern of different coral species, are conducted.

Monitoring of endangered / threatened species

Regular monitoring of endangered / threatened species like sea turtles, sea horses, and mollusks is in progress.

Fish Spawning Aggregations

Reef fish spawning aggregations (FSA) are a vital part of the cycle of many commercially important fishes. SDMRI is involved in the FSA survey in the Gulf of Mannar since 2007 in order to collect the baseline data on the reef fish spawning aggregations, species, season, and habitats. The data would help not to protect and conserve the fishery resources and their spawning sites for sustainable utilization through proper management strategies, but also would assist in further regular monitoring. The survey is in progress.

Aquaculture and sea ranching

The research work on hatchery technology development of commercially important shellfishes like cephalopods (squids, cuttlefishes and octopus) gave very successful results. These studies are mainly conducted to perform sea ranching of hatchery raised juveniles into coastal habitats in order enhance natural stock and to maintain ecological chain.

The pilot scale project on "Seahorse population recovery" implemented by Tamil Nadu Forest Department through SDMRI proved great success in 6 month with the laboratory production of 571 young one and successfully sea ranged in 2010.

Biofouling

Biofouling is a unique phenomenon in marine ecosystem often resulting in damages to man-made structures and corrosion. SDMRI is studying the biofouling sequence in Tuticorin coastal waters. Also, investigation is being carried to find out a non-toxic and eco friendly antifouling substance from marine organisms.

Pollution

TBT (Tributyltin), used as a toxic biocide in marine antifouling formations, is an endocrine disrupter in molluscs with females developing male sex organs (imposex) at very low concentrations. Imposex in marine gastropods is considered as a bio-indicator of TBT pollution. First imposex incident along the east coast of India was recorded by SDMRI at Tuticorin in the year 2002. SDMRI is monitoring the imposex in marine gastropods along Southern coast of India from Visakhapatnam on the east coast to Mangalore on the west coast. So far, imposex has been observed in six gastropod species along the east coast. Four species exhibited advanced stage of imposex, which is considered as the last fertile stage.

Monitoring of sedimentation in coastal ecosystem

SDMRI is conducting this study in Gulf of Mannar and Palk Bay by fixing sediment traps near the reefs in different directions to study the sedimentation rates due to different current patterns. The sampling is carried out once in a month to study the total quantity and grain size of the deposited sediments. This study has been initiated in Gulf of Mannar since 2003 and in Palk Bay since 2007.

Marine Natural Products

Marine organisms are rich in novel chemical substances of biomedical importance. Investigations are being carried out in SDMRI to find out a unique compound of value to humans. Marine organisms like mollusks, ascidians, seaweeds, sea grass, mangrove, bacteria etc are screened for bioactivity. The active substances are screened for pharmacological property also.

Microbiology

SDMRI is the Australian Quarantine and Inspection Service (AQIS) approved certifying laboratory for microbial quality of coir pith products exported to Australia.

The symbiotic/surface-associated bacteria from the marine environment are isolated and screened for bioactivity. The role of microbes in seafood processing is very important. So, the microbial quality of the seafood is assessed at the fish landings.

Seafood processing

Research work involves development of value added products using under utilized marine mollusk resources. Popularization of the newly developed products among the local community is also going on.