: Research undertaken by Fisheries Development Officer, Gadwal, research scholars and a faculty member of Osmania University, Hyderabad, has revealed that feral fish are causing the decline of presence of other species of Major Indian Carps, Minor Indian Carps and Catfish in river Krishna damaging the piscine diversity of the second largest river in South India.
The four-member research team led by Fisheries Development Officer, Boini Laxmappa observed the presence of Indian Major Carps has been declining year by year, while the population of Feral Fish Nile Tilapia ( Oreochromis niloticus ), which was introduced for aquaculture purposes in India in 1987, has been going up.
Mr. Laxmappa, faculty member at Department of Zoology Prof. Jithender Kumar Nayak, scholars S. Vamshi and P. Sunitha had collected the samples from 15 fishing sites along the 250-km stretch of the river in Mahabubnagar district between January 2012 and December 2014.
During these three years, Mr. Laxmappa told The Hindu , the presence of all kinds of fish, particularly Indian Major and Minor Carps, has started declining.
70 species of Tilapia
There were about 70 species of Tilapia which were primarily found in the rivers of western Africa and the Middle East.
The Thilapia fish is known as most traded food fish internationally.
The fish was flown into the river from aquaculture farms during the recurring floods. The population of the fish has multiplied over the years.
Govt. urged to act fast
Mr. Laxmappa said the presence of Indian Major Carps declined from 11.91 per cent in 2012 to 9.63 per cent in 2013 and 6.96 per cent in 2014, while Tilapia presence increased from 35.99 per cent in 2012 to 42.01 per cent in 2013 and 48.82 per cent in 2014. During the same period, the population of Minor Carps, Catfishes and other fishes started declining gradually. The officer said that the Nile Tilapia is known for its notorious ability even in bad water and creates its own ecology and repopulates other native species.
Mr. Laxmappa said river Ganga faced a similar problem in the past.
The researchers said unless the government initiates a conservation plan, the Nile Tilapia will repopulate the indigenous species in the Krishna very soon.