Swarms of jellyfish have invaded the inland water bodies of Kochi, making life miserable for fishers.
The presence of the marine species has been reported from many parts of Vembanad lake. The jellyfish, which is a passive swimmer, flows along with the current. They get entangled in the stake nets, making fishery impossible during the infestation period, complain fishers.
It is during the peak summer months that jellyfishes moves from the sea to freshwater bodies. The animals usually settle down on the ocean floor and coral and rock structures. They also get attached to the sea walls and groynes that are laid in the sea for preventing sea erosion. As the salinity and temperature of the fresh water bodies increase during the peak summer months, they leave the ocean floors to the inland water bodies. It’s during March April period that the presence f the animals is recorded in Kochi, explained those at the Central Marine Fisheries Research Institute, Kochi.
Climate change, pollution and turbidity can trigger jellyfish bloom as they have the capacity to outlive the extreme conditions. They may survive in the inland water bodies during the pre-monsoon period and perish during the monsoon period when the water temperature and salinity come down with the influx of fresh water. The bloom would subside during the monsoon season, explained researchers.
Researchers have identified the species present in the Kochi estuary area as belonging to the genus “Acromitus”, which is a relatively harmless one. However, Chrysora, its cousin, which is known in local parlance as Theechori, could cause health hazards if one comes into contact with it. The Chrysora species could cause severe itching and other discomfort and in some cases, medical support may be needed, warned researchers.
Crambionella orsini, another variety of jellyfish, is harvested in large quantities by trawlers of Kollam, Kanyakumari, and Thoothukudi during November to be exported to south Asian countries. The tentacles of the species are used for export while the bell-like structure of its body is discarded.