Kochi, Dec 4 (UNI) The alarming intensity of ecosystem degradation in Kerala rivers will totally wipe-off the fish biodiversity in these rivers in the next 10 to 15 years, according to a study.
The four-year study, conducted by Dr B Madhusoodhana Kurup, T G Manoj Kumar and R V Radhakrishnan, scientists of the Cochin University of Science and Technology reveals that the ecosystems of major rivers like Bharathapuzha, Periyar, Kallada, Pamba and Kabbini were degrading at an alarming rate, which is manifested by the decline in the fish biodiversity of these rivers.
The 'health status' of the rivers were assessed through globally accepted indices like the Index of Biotic Intergrity (IBI) developed by the Ohio Environmental Protection Agency in Canada, Habitat Quality scoring (HQ) and Diversity Indices (DI).
'' Around 170 species of fish were present in the State rivers of which 18 were critically endangered and 39 endangered, and if the present situation continues, the fish population will be wiped off in the next 10 to 15 years,'' Dr Kurup told UNI.
He said the ecosystem degradation was a result of changes in morphology, substrata, instream cover, pollution, shrinkage of river width, reduction in flow rate and velocity and severity of drought in the rivers due to various anthropogenic interventions.
Dr Kurup said the present situation could be reversed only by reducing pollution, increasing flow rate, maintaining the river flora and banks, banning sand mining and proper guidelines for constructing check dams across the rivers.
The HQ scoring, which shows the ecosystem status of the rivers computed on the basis of 56 geo-bio-chemical and physical properties of the river system, should be at least 50 as per international standards for treating them under 'good health' category.
The health condition of Bharathapuzha and Kabbini is alarming as these rivers had low score values of 39 and 34 repectively. Pampa, Kallada and Periyar had score levels in the range of 40 to 45. The only river, which had healthy score was Chalakudy with a value of 57.
The IBI, which unfolds the relationship between fish community structure and habitat quality, should have a score of above 40 to denote a compatible situation.
The score value of Bharathapuzha, Pampa, Periyar, Kallada and Kabbini were in the range of 21 to 34 while the Chalakudy river had a creditable value of 44.
The study revealed that an imbalanced situation prevailed between the fish population and habitat, which further unfolds the severity of human interventions in the rivers of Kerala.