Tamil Nadu to incentivise Kakka Aazhi harvesting to curb alien species

CHENNAI: Even as the laboratory trials conducted by Dr MGR Fisheries College in Ponneri on invasive Charru mussel (Kakka Aazhi), confirming potential source for high-quality bio-fertilisers and mineral mixes for agriculture and aquaculture, the Tamil Nadu State Wetland Authority has decided to develop a commercial plan for local fishermen to enable sustainable harvesting and value addition.

Per the report submitted by the Authority to the southern bench of the National Green Tribunal (NGT), the laboratory trials on the mussel's meat, shell and byssus thread have been completed. Moreover, directions have been given to the fisheries college to initiate heavy metal testing, standardisation, and machinery procurement to expedite the project.

Meanwhile, areas of Kosasthalaiyar River and Ennore Creek, where the invasive mussels were removed by dredging, showed the presence of larval stages of native competitors and bio-indicator species such as yellow mussel, gastropods, fish larvae and others, highlighting the possibility of restoration of Ennore Creek ecosystem, the report added.

It may be noted that the NGT is hearing a case filed by Kumaresan Sooluran, a fisherman in Kathivakkam in Ennore, seeking directions from the Tribunal to remove the invasive species from the water body. While hearing the case, the Tribunal directed the Water Resources Department to dredge out the invasive mussels.

Based on the direction, the WRD commenced dredging for 1,700 metres from Kattupalli to Puzhuthivakkam, and works have been completed for 1,050 metres. About 2.60 lakh cubic meters of mussels and fly ash (from the thermal power plant) were removed. Moreover, the National Centre for Sustainable Coastal Management has been given an assignment to identify infested areas along the 20-km stretch of Ennore Creek and Kosasthalaiyar River.

The applicant also submitted that the government has combined the dredging operations for the removal of invasive species and fly ash, pursuant to orders of the Tribunal in two separate proceedings.

"Even the dredging that is currently taking place is happening in a completely unsystematic manner, which has led to different points of the subject area being dredged to different extents. The ideal depth for fishing grounds in this area is 3.2 – 5 feet. However, the ongoing dredging work has led to vast differences in the depth of the water body in the very same area, ranging from 14.75 to 1.29 feet," the applicant pointed out.