HYDERABAD: Red-bellied Pacu, a fish from River Amazon in South America, has made inroads into the aquatic ecosystem of Telangana, raising serious concern of alien species invasion of state’s river ecosystem.
Reports of the fish being found in East Godavari district of the neighbouring Andhra Pradesh date back to 2012 but a recently published study by B Laxmappa, District Fisheries Officer, Gadwal, reports that the fish has been spotted in Rivers Krishna and Godavari in Telangana state as well.
The fish is cultured illegally by some aqua-culture farmers as it has a high demand in the market. However, some of them escape from the aqua-culture tanks and enter the rivers and slowly start reproducing thus populating the waters.
The Pacu, a relative of the red bellied Piranha, is known to be a ‘vegetarian’ fish. As per records, it can grow up to 88 centimetre and weigh up to 25 kg.
However, there have been reports from various countries where the fish got introduced as alien species that during times of food scarcity they can turn carnivore and start feeding on other fishes too.
Alien species
Telangana’s rivers are increasingly becoming populated by alien fish species. Most of them have been let out into the natural ecosystems from aqua-culture tanks and aquariums where they are reared as ornamental fishes.
Laxmappa said, “There is a need for two things. One is conducting detailed studies at various water bodies across the state to assess population of alien fish species which gives a clear idea of the problem. The other is to have strict policy on aqua-culture and control of illegal fish tanks. Bio security measures should be enforced so that alien species do not get into natural ecosystem.”
dangerous waters
As per a study by B Laxmappa, state’s aquatic ecosystem is now home to alien fishes including:
Amazon sailfin sucker catfish (South America)
Pangasius (Southeast Asia)
Silver carp (Central and Southern China)
Grass carp (Region from Vietnam till Siberia)
Bighead carp (Southern and Central China)
African catfish (African continent)
Guppy (South America and the Caribbean)
Mozambique Tilapia (Southern Africa)
Giant Gouramy (Southeast Asia)
Mosquito Fish (southwest USA)
A major threat to local species, which has been raised earlier, is from Nile Tilapia, native to Egypt and parts of Africa. A study published earlier after analyzing fish catches from 15 sampling stations of River Krishna reported around 49 per cent of the catch was that of Nile Tilapia