Looking at the poor catch of the day, U.A. Ananthan, a fisherman of Venkitangu, a village on the banks of the Chettuva estuary, sighed deeply. The declining fish catch from the estuary, along the west coast of Kerala, has triggered a wave of worry amongst the fisher families living along its shore.
“The backwaters never used to disappoint us like this earlier,” says Ananthan, president of the Inland Fishworkers Welfare Society, Venkitangu, who has been fishing on the stretch from the Enamavu regulator to the Chettuva estuary for more than 25 years. Hundreds of families in Venkitangu, Mullassery, Manalur, and Engandiyur, who depend solely on fishing for their living, echo a similar lament. “There are no fish in the canal. Many times, we return almost empty-handed.”
Three rivers
The Chettuva estuary is a crucial fish habitat along the west coast of the country as it forms an integral part of the Kole wetlands ecosystem, a tropical wetlands hotspot and a designated Ramsar site. This estuary, starting from the Enamavu regulator with an opening to the Arabian Sea, covering approximately 7-8 sq km and fed by three rivers (Kechery, Puzhakkal, and Karuvannur), plays a vital role in the economic and ecological functioning of the region.
A recent study conducted by a research team from the Kerala University of Fisheries and Ocean Studies (KUFOS) on the ecosystem services of the Chettuva estuary also unveiled a decline in fish wealth in the area and significant loss of fish habitats.
The loss of fish habitats is mainly attributed to the reduced depth of the estuary and water-carrying capacity due to siltation, says G.B. Sreekanth, who led the KUFOS study.
“It is estimated that the depth has decreased by 1 to 1.5 metres over the last two decades. Unfortunately, the study was unable to accurately assess the decline in fish production resulting from the habitat damage as there is no prior fish catch data available for the region,” he noted.
80 tonnes of harvest
The study estimated a total fish harvest of about 80 tonnes for the period from April 2022 to March 2023 from the Chettuva estuary. Capture fisheries contributed 86% of this harvest, while aquaculture accounted for the remaining 14%. The approximate economic value of the harvested fish was ₹3.26 crore. The disposition of the fish catch from the estuary primarily includes fresh fish for local consumption (60%), exports, especially crabs (10%), drying purposes (20%), and consumption by local fisher folk (10%).
The estuary is facing widespread degradation, largely due to factors such as eutrophication, heavy metal pollution, indiscriminate fishing for fish and bivalves, resulting in significant alterations to estuary’s physical, biological, and structural properties, Dr. Sreekanth noted.
Just a narrow canal
“Over a period, especially after the 2018 floods, the stretch from Enamavu to Chettuva has been reduced to a narrow canal at many places due to siltation. Recently, when the main canal of the Kole system was dredged, the silt and sludge too reached the backwaters through the Enamavu regulator,” says Ananthan. “We have been protesting against dumping of water hyacinth and other weeds cleared from canals of the kole fields to the backwaters. These weeds affect fisheries,” he says.
The KUFOS study cited another threat to the estuary in the form of untreated sewage from nearby cities in the upper zone of the estuary. Excessive growth of green algae, aquatic vegetation, pufferfish and jellyfish blooms, otter populations during monsoon and post-monsoon seasons, and technical difficulties in fishing due to the presence of plastics and discarded shells are the other challenges.
Suggestions
The study highlights the urgent need for comprehensive action to protect and rejuvenate the Chettuva estuary’s fragile ecosystem. The key interventions suggested include: Ensuring proper functioning of sewage treatment plants; dredging to increase the depth from the Chettuva harbour region to Kunduvakadavu over a 4-5 km stretch; developing sustainable aquaculture systems; diversifying livelihood activities including integrated farming systems; mangrove conservation programmes to revive dead patches of mangroves and establishing patrolling and monitoring to control indiscriminate fishing practices in the Chettuva estuary. All these activities can be coordinated in a participatory mode with the support from local inhabitants, users of the estuary, organisations and line departments.
