Hyderabad: Fish at the Ameenpur lake near the city, recently declared a biodiversity heritage site by the Telangana state government, are under threat from an alien invasive fish species named Tilapia, a native of Africa.
Nine fish species have been recorded from the lake. Officials of the Telangana State Biodiversity Board say that all these species are under threat from Tilapia, introduced in India many years ago for commercial benefit because they breed agressively.Unlike other local fish, Tilapia breed more than once in a year. Of the nine species in the Ameenpur lake, only 4-5 were easily spotted and their population was very less.
A senior official of the board said, “While Tilapia is considered herbivorous, there are research papers which consider them omnivorous. If there is a decline in quantity of herbivore food they might start eating the local fish.”
The Ameenpur lake is not the only water body facing a problem from Tilapia; it is common to rivers and tanks in the state where aquaculture is practised.
A study conducted by the fisheries department of Telangana that analysed fish catch over two years from 15 sampling stations on the Krishna river found that a large percentage was of a variety of Tilapia called as Nile Tilapia, which is known to adapt easily and suppress the native species.
The study found that 36-49 per cent of the catch was of the Nile Tilapia variety. African catfish, another invasive alien species, turned up in nearly 5 per cent of the catch.
Other alien species like silver carp, grass carp and common carp which were introduced for boosting fisheries are also posing a danger. Gambusia, introduced for killing mosquito larvae, has been found to be invasive in some water bodies.
