Question

Which of the following is an example of alien species invading a new ecosystem resulting in biodiversity losses?
A) Introduction of Nile Perch into Lake Victoria in East Africa
B) Introduction of Water Hyacinth into India
C) Introduction of African Catfish into Indian waters
D) All of the above

Answer 1

Any plant or animal species that is introduced into another region outside of its normal habitat is said to be alien. When this introduction affects the growth, distribution, and survival of species already present in the new location, it is said to be an invasive species.

Complete answer:

The Nile Perch was introduced in the 1950s into Lake Victoria as a boost to the fishing industry. However, this led to the extinction, or near extinction of several species of cichlid, and led to changes in habitat and water clarity. Besides destruction of the ecosystem, it damaged the local fishing industry. Option A is correct.
The water hyacinth was brought into India at the end of the 18th century because of its beautiful flowers. However they have such a dense, prolific growth, that light and oxygen cannot enter into the water bodies, killing the fish and submerged plant species. Along with species like lantana, the Water Hyacinth has caused great damage. Option B is correct.
The African catfish Clarias gariepinus was introduced illegally into India because of its ability to grow in waters that are very poor quality. It very quickly spread and has colonised water bodies all over including those in national parks. This has severely damaged the populations of native fish species, and the ecosystems around them. Option C is correct.
As all three options are correct, the answer to this question is option D.

Hence the correct answer is option ‘C’.

Note: Another extremely invasive species is the giant African snail, Achatina fulica. One of the most invasive species in the world, it not only affects the food chain, but is also a major agricultural pest.