Question

Which of the following shows catadromous and anadromous migrations respectively?
(A) Eel
(B) Clarias
(C) Salmon
(D) Both A and C

Answer 1

In this case we must know the exact definitions of the both the migrations that are catadromous migration and anadromous migration. Also we should be aware about some common examples of each migration respectively.

Complete step by step answer
Let’s first see definition of both the migrations respectively and also some common example of each migration:
A fish which is born in fresh water and spends most of its life span in the sea but it again returns to freshwater to spawn(to produce or deposit eggs) , these types of migration is called anadromous migration.
Example: Salmon, Smelt, Shad and so on.
A fish which mostly lives in freshwater and it enters the salt or salty water just to produce eggs( to spawn), these types of fish migration are known as catadromous migration.
Most of the eels are catadromous.

So, option D is correct.

Additional Information:
Salmon fishes which are known in the category of anadromous fishes, travel long distances in the sea and run up in fresh water to produce and lay eggs. After laying the egg, the fishes return to their feeding places in the sea.
Eel which come under catadromous fishes, travel several thousand km starting from rivers to the spawning grounds in sea. After they lay their eggs, the river dies and the larvae drift back to the freshwater. It almost takes three years to reach back the rivers.
Amphidromous fishes are those for whom migration from fresh water to sea or from sea to fresh water is not for the reason for breeding. It occurs regularly at definite stages of their life cycle. For example: myers.
Potamodromous fishes are such whose migrations are limited to freshwater only. For example: carps and trout.

Note
Key points to remember are: Salmon belongs to anadromous fishes/migration and eel belongs to catadromous fishes/migration. Also the main thing is we should know the definition of each migration and the reasons for their migration.