Question

Which one of the following fish is being illegally introduced for aquaculture purposes and is posing a threat to the indigenous catfish if Indian rivers?
A.Clarias gariepinus
B.Nile perch
C.Climbing perch
D.Protopterus

Answer 1

Hint: The African catfish grows fast and can tolerate poor water quality conditions and it can be cultured in dense numbers. The fish can breathe air and can crawl on dry ground and even it can survive in mud during the rainy season.

Complete step by step answer:
-Clarias gariepinus, also known as the African catfish, has been illegally introduced for aquaculture purposes and is posing a threat to the indigenous catfish of Indian rivers.
-In India, the Clarias gariepinus is a banned variety of fish. It is a black and shiny eel-like species that can be cultured illegally in water bodies across South Indian states like Andhra Pradesh and Kerala, and some East Indian states.
-This fish was first noticed in Andhra Pradesh – in a biodiversity hotspot of Indian aquaculture. This fish has colonized in major water bodies like rivers, invaded wetlands etc. -This fish has been spotted across all over the country – ranging from the Bharatpur Bird Sanctuary, Rajasthan in North India to the Periyar National Park, Tamil Nadu and Kerala border in South India.
-The fish was first introduced illegally in Brazil, Vietnam, Indonesia and then came to India for aquaculture.

So, the correct answer is option A.

Note:
Since the fish has spread into natural water bodies, it affects the native fish species in many ways like genetic impact, introduction of diseases as well as ecological impacts such as predation, competition and environmental modification is also done by this African catfish. The Indian government has forbidden its culture in ponds and tanks but several state governments are not enforcing the banning law and culturing it which leads to illegal farming of the species and makes it a threat to the other Indian water species.