In a composite fish culture system, which one of the following species functions as a bottom feeder?

Correct Option

The correct option is

Mrigal

Explanation

Composite Fish Culture (Polyculture) is a method of aquaculture where multiple fish species with compatible but distinct feeding habits are reared together in a single pond. This ensures that food resources in all ecological zones of the water body are utilized efficiently without inter-species competition.

The species are selected based on their feeding zones:

• Surface Feeders: These species feed on zooplankton and phytoplankton found in the upper layer of the water. Examples include Catla (Catla) and Silver Carp.
• Column Feeders: These species inhabit the middle zone of the pond. An example is Rohu (Labeo rohita).
• Bottom Feeders: These species forage at the bottom of the pond, consuming decaying organic matter and detritus. Examples include Mrigal (Cirrhinus mrigala) and Common Carp.
• Weed Feeders: Species such as Grass Carp feed on aquatic macrophytes and weeds.

Therefore, Mrigal is the species that functions as a bottom feeder in this system.

Key Takeaway: In a standard composite fish culture system, Catla occupies the surface zone, Rohu occupies the column zone, and Mrigal occupies the bottom zone.