Question

What is TRUE for Tenualosa ilisha?

• A. It matures and spawns in marine water
• B. It matures and spawns in freshwater
• C. It matures in marine water and spawns in freshwater
• D. It matures in estuary and spawns in freshwater

Hint:

Remember the difference:
1. Anadromous (e.g., Hilsa, Salmon): Sea $\rightarrow$ River (for spawning).
2. Catadromous (e.g., Anguilla eels): River $\rightarrow$ Sea (for spawning).
Hilsa is the most important anadromous fish of the Indian subcontinent.

Answer 1

The Correct Option is C

Step 1: Understanding the Question:
The question asks about the life cycle and migratory behavior of Tenualosa ilisha, commonly known as the Hilsa shad.
Detailed Explanation:

• Anadromous Migration: Tenualosa ilisha is a classic example of an anadromous fish. This means it lives most of its life and reaches maturity in the marine environment (sea) but migrates into freshwater (rivers) specifically for the purpose of spawning.

• Life Cycle:
• Adults live in coastal marine waters.

• During the monsoon seasons, they ascend into large rivers (like Ganga, Hooghly, Padma) to spawn.

• Spawning occurs in the freshwater reaches of these rivers.

• The young ones (known as Hilsa juveniles or Jatka) gradually migrate back to the sea to grow and mature.

• Analysis of Options:
• Option (A) is incorrect because they migrate out of marine water to spawn.

• Option (B) is incorrect because they do not spend their entire life cycle in freshwater.

• Option (D) is less accurate because while they pass through estuaries, the primary growth and maturation phase is marine.

Step 2: Final Answer:
The correct statement is that it matures in marine water and spawns in freshwater.