Pollution and climate change have put 12 indigenous fish species on the brink of extinction in India. Research is being conducted in the area between Bengaluru and Melekote in 10 lakes by Dr. M. Ramachandra Mohan, HoD, Department of Zoology and some students.
“Of the 12 species, five are under the vulnerable category and the rest are endangered. Two foreign species are also in danger,” explained Dr. Mohan. The Karnataka Labeo (Labeo Calbasu) and Indian Glassy fish (Pseudambassis Ranga) are two of the at-risk species.
Climate change is impacting water temperatures, water chemistry, water levels and rainfall patterns. Habitat destruction is occurring too due to human activities like dam construction, and exploitative fishing practices.
“Despite this higher level of tolerance, neither the indigenous nor foreign varieties are able to sustain themselves in the 10 lakes which were part of the study. Agricultural pollution and destruction of lakes due to agricultural and layout encroachments are other major problems,” stated Dr. Mohan.
The presence of exotic species like carps, african catfishes and tilapia in the lakes doesn’t help matters either, because they can compete with the indigenous fishes for food and habitat.
The indigenous fish are not just isolated elements within the lakes, they are part of an ecological balance that was evolved over many years. if they all die, the lake ecology will also be altered permanently. Birds that live in the area, which eat fish they hunt for, and/or fish remains would have less to eat, and then their existence might also be threatened. Sometimes, when a native species, or more than one dies out, there can be a chain reaction within the interconnections between species.
If humans use the fish for food, their absence would obviously negatively affect them too.
Karnataka has about 201 freshwater fish species, and approximately 40 of them are in some state of vulnerability, so conservation measures are needed.