Question

In the polyculture of carps, the maximum production per unit area was achieved by research institutions with the following species combination

• A. Catla : Rohu : Mrigal : Silver carp
• B. Catla : Rohu : Mrigal : Common carp
• C. Catla : Rohu : Mrigal : Common carp : Silver carp : Grass carp
• D. Rohu : Mrigal : Silver carp : Grass carp

Hint:

Composite Fish Culture 6-Species Combination: Catla, Rohu, Mrigal (IMCs) + Silver carp, Grass carp, Common carp (Exotics) maximizes pond production per hectare.

Answer 1

The Correct Option is C

Step 1: Understanding the Concept:
Composite Fish Culture (6-species polyculture system): combining three indigenous Indian major carps with three compatible exotic carps to optimize all ecological trophic niches in the water column.
Key Formula or Approach:
\[ \text{6-Species Composite Fish Culture} = \underbrace{\text{Catla (Surface)} + \text{Rohu (Column)} + \text{Mrigal (Bottom)}}_{\text{Indian Major Carps}} + \underbrace{\text{Silver Carp (Surface)} + \text{Grass Carp (Macrophytes)} + \text{Common Carp (Bottom)}}_{\text{Exotic Carps}} \]

Step 2: Detailed Explanation:
In freshwater aquaculture technology (ICAR-CIFA Composite Fish Culture):
- 6-Species Composite Fish Culture System achieved record production yields ($10 - 15\text{ tons/ha/year}$) by utilizing all ecological feeding niches in a pond without interspecific competition:
1. Surface Feeders: Catla (zooplankton) $+$ Silver Carp (phytoplankton).
2. Column Feeder: Rohu (omnivorous filamentous algae periphyton).
3. Bottom Feeders: Mrigal (detritivore) $+$ Common Carp (benthic omnivore scavenger).
4. Macrophyte Feeder: Grass Carp (aquatic submerged vegetation, producing fecal pellets that fertilize bottom food webs).
- Therefore, the full 6-species combination maximizes production.

Step 3: Final Answer:
Therefore, maximum production was achieved with Catla : Rohu : Mrigal : Common carp : Silver carp : Grass carp, matching option (C).