Expert Advisory Details

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Posted by Guru Angad Dev Veterinary And Animal Sciences University, Ludhiana
Punjab
2022-07-12 14:14:26

Management of fish ponds in rainy season

Although monsoon is a favorable season for fish farming, smart water management skills are required to avert any unforeseen damage to fish ponds and loss of fish stock. Dr. Meera D Ansal, Dean, College of Fisheries, Guru Angad Dev Veterinary and Animal Sciences University, Ludhiana shared important management practices for fish farming in the monsoon season. She advised that keep the pond dykes be planted with grass to check erosion, However, in case water becomes muddy due to erosion, apply limestone in accordance with water pH. Further, leave about 2 feet of freeboard over the water surface for accommodating rainwater and preventing overflow. An automatic meshed overflow pipe may also be provided for maintaining desired water levels. Net fencing around the pond is recommended to prevent fish escape with overflow in case of high-intensity rainfall. The dykes shall be kept 3-4 feet raised above ground level, to fend off inflow from the catchment area, which otherwise may bring lots of organic load and pesticides from the adjoining agricultural fields and pollute the water.  

It is vital to ensure that water pH does not fall below 7.0, which is detrimental to fish survival and growth. To prevent such conditions, it is advised to sprinkle limestone on the pond dykes (@ 10 kg/100m2), so that it mixes with rainwater and neutralizes its acidic effects. Further, to prevent any chance of sharp decline in top layer pH, the surface wheel aerator shall be kept running during rainfall for proper mixing of water. Also, adjust feed quantity in accordance with temperature change to prevent wastage. 

As most of the fish species breed during monsoon, it is recommended not to fill the ponds with canal water during this season. In case it is the only source of water, fix a very fine mesh net on the mouth of the inlet pipe to check the entry of eggs and larvae of unwanted fish species (weed and predatory) into the pond. In case cloudy conditions prevail for long hours during daytime and plankton crop crash occurs due to rainfall, it is suggested to maintain oxygen level through an effective aeration method and stop feeding till the next sunshine. It is advocated to periodically replenish 20-25% of pond water with fresh water to maintain optimum pH and oxygen levels during this season, where nutrient-rich pond water can be efficiently utilised for irrigating paddy fields, with significant saving on fertilizer costs.