Posted on :- 11 Sep 2024

Description

Ammonia is a gas of great concern in aquaculture. Gaseous ammonia is primarily released from the gills of Fish, Prawns and Shrimps as a metabolic waste from protein breakdown and from the lesser secondary sources such as decomposition of uneaten feed and organic wastes by bacterial actions. Ammonia concentration is increased because of reduced algal population in the pond and due to reduced rate of assimilation of ammonia by plankton algae. Additionally, lower water temperature slows aerobic bacterial nitrification process whereby ammonia is converted to nitrates. High aquatic pH also severely accounts for the enhanced aqua concentration of ammonia. Ammonia is extremely toxic and its toxicity is attributed mainly to its un-ionized form. Ammonia tends to block oxygen transfer from the gills to the blood and can cause both immediate and long-term gill damages. The mucous producing membranes can be destroyed, reducing both the external slime coat and damaging the internal intestinal surfaces. Fish suffering from ammonia poisoning usually become sluggish, often remain at the water surface as if gasping for air. Dangerous short term levels of un-ionized ammonia are capable of killing fish over a few days starting at about 0.6 ppm. Chronic exposure to toxic ammonia levels as low as 0.06 ppm can cause gill and kidney damage, reduction in growth, brain malfunctioning and reduction in oxygen carrying capacity of the fish. Disease susceptibility also increases in fishes exposed to chronic ammonia intoxication. Since aquatic animals perform all their bodily functions in water, good water quality in aquaculture system should essentially be maintained, particularly in reference to ammonia concentration. (APPROX PRICE)