Two endemic fish varieties - catfish and eel - are feared to have disappeared from the Pamba.
No individuals of these species have landed in the nets of fishermen for the last three years triggering suspicion of their population loss. The catfish (Nadan Mushi) and the eel (Malanjil) were once found in abundance in the river system.
The disappearance of the popular varieties was noted during an evaluation of the harvested fishery wealth of the river by the School of Industrial Fisheries of the Cochin University of Science and Technology.
The three-year assessment of fish landing at six centres was carried out as part of a project “database on fish germplasm, capture fisheries and biodiversity threats of rivers of Kerala” for the Kerala State Council for Science, Technology and Environment.
A research team led by B. Madhusoodana Kurup, Director, School of Industrial Fisheries, had M. Harikrishnan and C.R. Renjith Kumar as members.
The analysis identified the presence of 60 fin fish species and one prawn variety in the river. Of this, 26 were regularly caught by the fishermen. This also included a few species namely Vaka Varal, Kooral, Manjakoori, Aral, Muthukila, Arinjil and Paral, which had high ornamental value in overseas market.
It was estimated that 42 tonnes of fish having ornamental value was being indiscriminately caught annually from this river. They were used either as poultry feed or manure. The annual average fish landing was found to be 394 tonnes worth Rs.3.70 crore.
The fishery wealth of the river was found to be dominated by Thooli. The other varieties that were netted include Varal, Vala, Karimeen, Vayambu and Karuva Paral. The researchers had earlier developed captive breeding techniques for the species and carried out ranching for restoring its population, the report said.
Habitat decline and degradation due to increased sedimentation in river bottom, pollution from sewage and agriculture were rampant in the river.
Illegal fishing activities using poison, electricity and some plant extracts, poor water quality and invasion of exotic and alien fish species were also posing serious threats to the fish germplasm.
The study recommended setting up of a local-level management body for the conservation and judicious utilisation of the fishery resources.
