Giant dredgers in peak summer? They’re fighting mussel invasion

Chennai: It's peak summer in Chennai, so what are giant dredgers, excavators, and boats doing along the coast? Fighting Mytella strigata, an invasive American mussel species locally known as ‘Kaaka Aazhi'.
These mussels, believed to have arrived via ballast water discharged from ships, rapidly colonized a 1.7-kilometre stretch of the Ennore-Pulicat backwaters. Their proliferation threatens native prawn populations and disrupts the delicate ecological balance of the wetlands. To make matters worse, the mussels embedded themselves in layers of fly ash discharged from the nearby thermal power station operated by Tangedco, making their removal significantly more complex.
National Green Tribunal earlier directed the state's Water Resources Department (WRD) to recover 28 crore from Tangedco and use it for immediate cleanup operations. Acting on the order, the WRD recently launched a large-scale dredging drive. So far, two dredgers, four hydraulic excavators, two boats, and a 40-member crew managed to extract nearly 2 lakh cubic metres of a dense, mixed sludge of fly ash and mussel clusters from an 800-metre stretch. Officials estimate that the dredging and restoration of the full 1.7-km affected backwater zone will be completed by the end of May 2025.
To curb further spread of the mussels and avoid re-infestation in the dredged zones, experts from Dr MGR Fisheries College and Research Institute in Ponneri have been roped in. Pilot studies aimed at devising sustainable removal techniques and exploring value-addition possibilities from the extracted mussels are underway at an estimated cost of 33 lakh. These studies are expected to serve as a model for tackling other infested pockets in the Ennore creek.
However, the NGT pulled up the state for the delay. Despite nearly two years since the issue was flagged, authorities are yet to assess the full extent of the infestation.