THOOTHUKUDI : Artisanal fishing activities that are linked to livelihood of fishermen have rendered little success to the conservation efforts of coral reefs at the Gulf of Mannar.
An analysis of fishing practices of Gulf of Mannar Biosphere Reserve conducted by Thoothukudi Fisheries College and Research Institute (FC&RI) reveals that coastline along the bay has witnessed an increase of 34 per cent of population, which translates to 57 per cent increase in the number of mechanised trawlers and 71 per cent increase in vallam (motorised country boat) since 1990's. Many farmers and palm climbers have also turned into fishing, the report says.
Marine researchers told TNIE after two of the 21 islets of Gulf of Mannar - Vallanguchalli and Poovarasanpatti - submerged, the conservation projects have technically been enhanced.
Moreover, 29 per cent of the reef area has been degraded due to various anthropogenic and natural factors. Nearly 20 per cent of the seagrass beds spanning to an extent of 152 square kilometres in the Gulf of Mannar region, have been damaged so far, they said.
"The population of dugong, also called as sea cow, an umbrella species of the region, that relies on the seagrass meadows has drastically declined owing to the destruction of seagrass," they pointed out.
Among many of the artisanal fishing practices in vogue is the shore seine operation (kara valai), in which a group of nearly 20 fishermen manually bottom trawl from the shore. Along with fishes, it sweeps the sea grasses, dead corals, juvenile fish away and disturbs all benthic flora and fauna.
A marine researcher, K Diraviam Raj, in his study published in 'Indian Journal of Marine Sciences' said an average of 67.76 per cent of the catch using shore seine nets are found to be juveniles. Similar to the shore seine operation is the push-net operation that is practised off the shore, he added.
The conch diving that is practised only in Thoothukudi causes damage to the sea bed, as the divers dig the bed haphazardly for sunken chunks which has good market value in the fancy industry, the researchers say.
The researchers said the promotion of Kappaphycus alvarezii along the calm waters of Gulf of Mannar is becoming a grave threat to the coral reefs. Kappaphycus alvarezii spreads over the water surface and hinders photosynthesis process in seagrasses. It also leads to coral mortality. These consequences damage fish habitat that result in migration of fishes. The International Union for Conservation of Nature (IUCN) had categorised Kappaphycus alvarezii in the 'red list', he said.
Referring to a study conducted on the bio-invasion of the Kappaphycus alvarezii in Krusadai island, the marine biologists said it destroyed over 1.2 square kilometres of coral colonies within two years.
The researchers said the dependence of the people on the resources should be reduced through alternative income generation and livelihood security programmes, so that conservation efforts could bear fruit.
State secretary of fishermen association attached to AITUC, CR Senthilvel, said such pre-historic practices exist only in the Gulf of Mannar region. The damages caused are low when compared to the magnitude of the bottom trawling by mechanised vessels, he said. These fishermen remain poor because they have little access to advanced technology. "So, the government should help them find alternative livelihood programmes related to the fishing industry," he said.
Seeking anonymity, an official of Gulf of Mannar Forest Biosphere told TNIE trap fishing has greatly reduced after 2016. "The government is promoting alternative livelihood programmes including palmyra value added products, manufacturing fish pickle, karupatti for fishermen through village marine conservation and eco-development committees being operated from 252 villages and 271 women self help groups functioning in coastal villages. These committees were provided a fund of `6 crore during the fiscal 2021-22," he said adding these alternative livelihood measures will yield good results in another few years.
Artisanal fishing activities
Shore seine fishing, Trap fishing, Spear fishing, Conch diving, Push-net operation, Poaching of ornamental fish, Cultivation of exotic weeds such as Kappaphycus alvarezii.