Tamil Nadu is blessed with the second-longest coastline in India 1,076 kilometres stretching from Pazhaverkadu in Thiruvallur district to Ezhudesam in Kanyakumari district.
Sixty per cent of the state’s population live within 100 kilometres of the coast. The rivers which originate from the Western and Eastern Ghats, join the sea in the state.
About 26 towns and 2,390 villages are located along the coast. About a million fishers in Tamil Nadu, who live in 608 fishing villages, depend on fisheries for their livelihood. The livelihood of the fishers is threatened due to depletion of natural resources owing to habitat destruction, pollution, and other factors.
In September 2019, the fishing community in Ramanathapuram, Tamil Nadu, was shocked as the sea water turned green and fish died in the thousands.
Scientists from the Central Marine Fisheries Research Institute in Kochi visited the spot, carried out a study and came to the conclusion that the incidents had taken place due to the sudden blooming of Noctiluca, a type of marine microalgae.
The cause of the fish deaths was assessed to be oxygen depletion caused by the sudden blooming of the microalgae. The fishers were advised not to worry as the algae would dissipate when there was a downpour and strong currents in the sea.
Scientists from the National Centre for Coastal Research (NCCR), Mandapam, have said that the Noctiluca scintillans algae bloomed suddenly due to the discharge of ballast water, subsequently causing the fish to die-off and the sea water turning green.
Blooming of the algae took place between the Gulf of Mannar and Mannar areas off the Sri Lankan coast. It could be possible that the discharge of the ballast water was from the Lankan coast.
Down To Earth 2019