With reference to the role of biofilters in Recirculating Aquaculture System, consider the following statements:
1. Biofilters provide waste treatment by removing uneaten fish feed.
2. Biofilters convert ammonia present in fish waste to nitrate.
3. Biofilters increase phosphorus as nutrient for fish in water.
How many of the statements given above are correct?
(a) Only one
(b) Only two
(c) All three
(d) None
Answer: B
The correct answer is (b) Only two.
Let’s analyze each statement:
- Biofilters provide waste treatment by removing uneaten fish feed.
- This statement is correct. Biofilters in a Recirculating Aquaculture System (RAS) help in waste treatment by removing uneaten fish feed and other organic matter from the water. The biofilter media provide a surface for beneficial bacteria to grow, which help in breaking down and removing these wastes.
- Biofilters convert ammonia present in fish waste to nitrate.
- This statement is also correct. One of the primary functions of biofilters in a RAS is to convert toxic ammonia (produced from fish waste) into less harmful nitrate. Beneficial bacteria in the biofilter media perform nitrification, a process where ammonia is first converted to nitrite and then further converted to nitrate.
- Biofilters increase phosphorus as a nutrient for fish in the water.
- This statement is incorrect. Biofilters do not increase phosphorus as a nutrient for fish in the water. Their primary role is to remove wastes and convert ammonia to nitrate. Phosphorus levels in the water are managed through other means, such as fish feed formulation and water quality management.
Therefore, out of the given statements, only two (Statement 1 and Statement 2) are correct. The correct answer is (b) Only two
