Invasive Kakka Aazhi spreads to Pulicat Mouth
Kaaka Aazhi had grown aggressively up to a height of 0.15m to 0.30m below from the top of water level
CHENNAI: An analysis done by the state water resources department (WRD) has revealed that invasive Charru Mussels (Mytella strigata), commonly known as Kakka Aazhi, has spread to Pulicat mouth Kosasthalaiyar backwater and Ennore Creek.
According to a report submitted by the department to the southern bench of National Green Tribunal, it is observed that, the species like Charru Mussels have been spread over a length of 6 kilometres from Kosasthalaiyar backwater to Ennore Creek and Pazhaverkadu (Pulicat) mouth, which also affected the growth of white prawns, tiger prawns black prawns, sand prawns, green crab, mullet and others.
"Invasive species Mytella strigata native to South America, spread along the stretch of the Kosasthalaiyar backwater, Buckingham canal and Pazhaverkadu mouth, " the report said.
Kaaka Aazhi had grown aggressively up to a height of 0.15m to 0.30m below from the top of water level. Due to Kaaka Aazhi infestation, severe choking with 0.30m depth of sludge and also disruption to the boat movement in the Kosasthalaiyar backwater.
Generally the Kosasthalaiyar River acts as a breeding ground for crustaceans like prawn, crab and molluscan species like shells, calms. Owing to the presence of Charru Mussels in the Kosasthalaiyar backwater Buckingham canal and water bodies, the vast diversity of the flora and fauna species has been drastically depleted.
In a petition to the Tribunal, local fisherman S Kumaresan stated that the mussels spread like a carpet over the river and canal bottom preventing prawns from grazing or burying themselves in the river sediment. Phytoplankton availability is also depleted, as a result of which shrimps cannot survive in these waters.
A technical team has already inspected the affected areas in October, 2022 and recommended that the Kosasthalaiyar River at Karrukumaram Paadu (fishing ground) area is required to be dredged in order to facilitate to boat movement in the river and ecological development of fishes, prawns, and crabs to ensure fishermen's livelihood.
On the other hand, the recent oil spill incident in Kosasthalaiyar River and Ennore Creek did not affect the invasive species, while some of the native species died. "Kakka Aazhi would usually thrive in a polluted environment, " Kumaresan said.