Importance of Plankton in Fish Culture Pond

Characteristics of Plankton as Fish Food

• It has easy availability.
• It is easy to handle.
• It performs as a feed.
• Its production cost to serve as feed is low and the rate of capital return is viable.
• It has particle size of 10-500μm dia.
• It stays suspended in the water column for a considerable period (suspendability / water stability).
• It does not pollute the water system.
• It possesses attractability as a feed for the fish.
• It is acceptable, palatable and possesses a low BOD, reducing any chance of rapid microbial degradation.
• It has an appreciable shelf life.
• It is easy for culture / rapid propagation.                                                                                   

Other Roles of Plankton:

• Plankton regulates transparency and dissolved oxygen thereby regulating sun’s ray penetration and temperature and decreasing accumulation of CO₂, NH₃ NO₂, H₂S etc. in water.
• Pond with a definite phytoplankton is observed to keep prawns calm and reportedly minimize cannibalism. They consume phytoplankton and thereby regulate NH₄⁺ and tie up with heavy metals.

The proximate composition and nutritional details of some natural food groups of the plankton species

Microalgae

• The nutritional status depends on the cell size, digestibility, production of toxic compounds and biochemical composition.
• Although marked differences are exhibited, the range for the level of protein, lipid and carbohydrate are 12.0-35.0%, 7.2-23.0% and 4.6-23.0%, respectively on dry weight basis.
• Microalgae could be considered as a rich source of highly unsaturated fatty acids (HUFA) and ascorbic acid (0.11-1.62% dry wt).

Cladocerans

• It has low essential fatty acid contents, particularly HUFA.
• Daphnia contains broad spectra of digestive enzymes, such as, proteinases, peptidases, amylases, lipases and even celluloses, which ultimately facilitate extrinsic digestion in the predator fish.

Copepods

• These contain 44-52% protein and a good amino acid profile with the exception of methionine and histidine.