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| Last Updated:: 08/10/2015

These migrants need attention, too



Our fish are moving north.


Until about the mid-1980s, important fish species such as mackerel and oil sardines used to be present no further north than the Malabar upwelling zone off the Kerala coast. Because of global warming, sea surface temperatures along India’s west coast rose by 0.6 degrees Celsius over 1967-2007, according to the Kerala State Action Plan on Climate Change. Consequently, these fish species began to find the ocean waters further north also rather salubrious. In the last thirty years, the northern boundary of their range — the geographical area over which any given species is to be found — has extended a staggering 650 kilometres. Having moved beyond Karnataka and Maharashtra, they can now be found in waters off Gujarat. Off India’s eastern coast too, the mackerel’s range has shifted north, from the Andhra coast earlier to waters off parts of West Bengal presently.



This shift in the range of species is also taking place in India’s rivers. Along the Ganga for instance, four species of warm water fish can now be found swimming further north, up to Haridwar, as the average minimum temperatures of river waters in this stretch had warmed by 1.5 degrees Celsius by 2009 over the 1970-1986 average.




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