BENGALURU: Interlinking of rivers and other factors has led to a lot of exotic, invasive species of fish being introduced into our rivers, said Jagdish Krishnaswamy, Senior Fellow, Suri Sehgal Centre for Biodiversity and Conservation, ATREE.
These species often do well when there is a disturbance in the flow or degradation in the condition of rivers. They are able to compete better than native species, he said, urging people to exercise caution when linking rivers.
He was talking at the first in the lecture series of ‘Submerge’, a 45-day exhibition by Bangalore Science Gallery at Bangalore International Centre, on Sunday.
Krishnaswamy said that in some parts of India, you have piranhas biting people. “When the Krishna and Godavari rivers were linked, you had exotic species jumping from one river basin to another. It poses a lot of problems in terms of native fish productivity and the wellbeing of people who bathe and fish in these rivers.”
He saw a possible solution in retaining groundwater and river water with a robust policy on saving water.
Agriculture and industry must move to less water-intensive practices, he said. For instance, a water-intensive crop like sugarcane which does not provide essential nutrients can be reduced in scale, and less water-intensive millets that are high in nutrition can be cultivated. While food pattern changes would take time, like shifting from rice to millets — although parts of Karnataka traditionally eat millets — he said incentives should be given to farmers to grow millets.
He said that water conservation and management strategy would have better impact in terms of ensuring flow of river downstream, and one needs to relook at industrial and agricultural activities upstream.
‘River water flowing into sea not a waste’
Krishnaswamy also pointed to the need to relook at the notion that river water flowing into the sea is a waste of resource. “Sediment which reaches the sea is important for sustaining mangroves that sequester carbon dioxide. Productivity of estuarine and coastal fisheries also depends on this confluence. Carbon brought by the river is deposited in the bottom of the sea, so there is a mitigation of carbon content,” he said.