Question

Given below are two statements:
Statement (I): In the recirculatory aquaculture system, requirement of water is minimal.
Statement (II): In the recirculatory aquaculture system, water pass through biological filters.
In light of the above statements, choose the most appropriate answer from the options given below.

• A. Both Statement (I) and Statement (II) are correct.
• B. Both Statement (I) and Statement (II) are incorrect.
• C. Statement (I) is correct but Statement (II) is incorrect.
• D. Statement (I) is incorrect but Statement (II) is correct.

Hint:

RAS = Conservation of water + High density stocking + Intensive filtration. If a question mentions "water reuse" or "biofilters," the answer is almost certainly RAS.

Answer 1

The Correct Option is A

Step 1: Understanding the Concept:
Recirculatory Aquaculture Systems (RAS) are intensive farming systems designed to minimize environmental impact and maximize production per unit of water and land.
Detailed Explanation:
Analysis of Statement (I): In traditional pond or raceway culture, water is used once and discharged. In RAS, up to 90-99% of the water is treated and reused within the system. This drastically reduces the daily water requirement compared to any other aquaculture method. Thus, Statement (I) is correct.
Analysis of Statement (II): To reuse water, it must be treated to remove metabolic wastes, primarily ammonia. Water in RAS passes through biological filters containing nitrifying bacteria (Nitrosomonas and Nitrobacter). These bacteria convert toxic ammonia into nitrite and then into relatively harmless nitrate. This biofiltration is the "heart" of any RAS. Thus, Statement (II) is correct.

Step 2: Final Answer:
Both statements are correct as they describe the core operational principles of RAS.