Question

Which of the following fish led to the extinction of an ecologically unique assemblage of more than 200 species of cichlid fish in the lake Victoria of E.Africa?
A.Catla catla
B.Dog fish
C.Nile perch
D.African catfish

Answer 1

Hint: The term extinction is defined as the death or termination of a particular living organism which can be a plant or animal either due to the natural process of evolution or human activities.

Complete answer:
Lake Victoria is the world’s largest tropical lake which consists of approximately 500 different species of cichlid fish. They belong to the class Actinopterygii and characterised by fusion of the lower pharyngeal bone into a tooth bearing structure, a single nostril on each side of the forehead and no bony shelf below the eye. The extinction of cichlid fish in Lake Victoria occurred due to the introduction of other invasive fish species. Among the options given in the question Catla catla is a freshwater fish belonging to the class Cyprinidae. They are characterised by a large and broad neck, upturned mouth and protruding lower jaw. Dog fish belongs to the class Squalidae and do not contain dorsal and anal fin. Nile perch is also a freshwater fish belonging to the class Actinopterygii. It has dark black eyes and bright yellow outer ring and is also one of the largest freshwater fishes. African catfish belong to the class Actinopterygii and have an eel-like appearance. The extinction of cichlid was mainly due to introduction of Nile perch in Lake Victoria.

Hence, the correct answer is option (C)

Note: Nile perch was introduced in Lake Victoria in the 1950s and has been seen to be ecologically disruptive as it caused extinction of a wide range of species from the lake leading to a change in the native ecosystem. Nile perch led to extinction of cichlids because it used to feed on them. Apart from this they also contributed in indirect ways to deforestation and soil erosion.