Phytoplankton

Aquaculture organisms have to obtain all their nutritional requirements, except for part of the mineral requirements, through the food they consume. In nature, most of the organisms subsist on live food consisting of plants and animals obtained from the environment, but some do ingest and possible utilize detritus along with associated organisms. The initial source of food for many larval organisms is phytoplankton. This is probably associated with the size of the larvae at hatching. After a certain period of time the larvae of most species can be fed exclusively on zooplankton or a combination of plant and animal matter i.e. plankton. The term plankton can be defined chiefly as microscopic drifting or floating organisms in the sea and fresh waters and may be having feasible floating devices. The plant components of all the plankton are the phytoplankton and are the primary producers for the entire aquatic body, whereas the animal components of the plankton are the zooplankton and are the primary consumers.

Phytoplankton
Aqua-farmers pay much attention to the colour of the pond water. In other words, they place great importance on the promotion of phytoplankton in pond water. In nursery and grow-out ponds, they are generally produced as a result of biological cycle initiated by mineral nutrients in water. Using the sun‘s heat and light they transform the inorganic matter and carbonic acid in solution into organic matter, in the form of vegetable tissues consisting of a variety of phytoplankton.

The following objectives are associated with the phytoplankton:

• To increase dissolved oxygen and to decrease toxic gases like ammonia, nitrite, hydrogen sulfide, methane, carbon dioxide in pond water.
• To stabilize pond water quality and to lower the content of toxic compounds.
• To make use of plankton as a natural feed.
• To provide shade and to decrease cannibalism.
• To increase and stabilize water temperature
• To minimize pathogenic and unwanted microbial population by competing with the available nutrients in the water.

So, Phytoplankton plays a significant role in stabilizing the whole pond ecosystem and in minimizing the fluctuations of water quality.