Question

Triploid fish is a

• A. A fertile fish and capable of producing young ones
• B. Hermaphrodite
• C. Semi-fertile
• D. Sterile fish

Hint:

Genetic Mnemonic:
- Gynogen = All Female.
- Androgen = All Male.
- Triploid = Sterile (Good for growth and environment).

Answer 1

The Correct Option is D

Step 1: Understanding the Question:
The question asks about the reproductive status of a "triploid" fish, which is an organism that has three complete sets of chromosomes ($3n$) instead of the normal two sets ($2n$).
Detailed Explanation:

• Production of Triploids: Triploid fish are produced by subjecting newly fertilized eggs to environmental shocks (temperature, pressure, or chemical shocks). This prevents the extrusion of the second polar body, resulting in three sets of chromosomes ($2n$ from the egg + $n$ from the sperm).

• Sterility (D): Triploid organisms are almost always sterile. This is because the three sets of chromosomes cannot pair up correctly during meiosis (the cell division process that produces gametes). This leads to the failure of gonad development or the production of non-functional eggs and sperm.

• Advantages in Fisheries:
• Growth: Since they do not waste energy on gonad development and spawning behavior, triploids often show faster growth rates and better meat quality.

• Escape Management: Sterile triploids (like triploid grass carp) can be used for weed control without the risk of them becoming an invasive species by breeding in the wild.

Step 2: Final Answer:
Triploid fish are functionally sterile.