Fish Farming: March/April to October/November is the best period for fish growth in north-western states and smart management tips can increase production as well as farmers income significantly.
Dr. Meera D. Ansal, Dean of College of Fisheries, Guru Angad Dev Veterinary & Animal Sciences University says that although, summer season is favorable for fish growth, but protection against temperature exceeding 350C is essential. Hence, farmers must maintain 5-6 feet water depth during peak summer months to provide adequate comfortable zone to the fish below the hot surface layer.
Dr. Meera apprised to check ‘Oxygen’ levels during this period, which may drop to lethal levels during dawn due to enhanced biological activity. Hence, ventilate the ponds during early hours of the day before sunrise, either by putting fresh water or using aerators, to maintain oxygen levels above 5 mg/l. She said if disease and fish gasping for air at water surface is observed, provide aeration, add fresh water, apply disinfectant & suspend manuring and feeding to improve the water quality. Periodic water exchange will further boost fish growth and production.
She advised adding fresh water to the ponds and using the nutrient-pond water for irrigating the paddy fields during this period as it will improve water quality in the pond & reduce fertilizer requirement in the paddy fields as well.
Sustained plankton (natural food) production in the pond and feeding with quality feed according to recommended regime helps in achieving optimized production targets. Keep the pond rich in plankton through mixed utilization of organic manures & inorganic fertilizers.
Fish farmers must use farm-made pellet feeds to reduce feed wastage and achieve better feed conversion efficiency. In case water turns dark green, brown or, greenish-brown in color and a green, brown, or red-colored algae mat appears on the water surface then suspend manuring and feeding till the condition improves back to normal.
Also, check day-night variation in water pH that may cross 9.5 during peak day hours and drop below 7.0 during night hours. Maintain optimum pH range (7.5-8.5), with lime or alum/gypsum application as per expert advice.
Farmers must refrain from anticipating higher production through increased inputs i.e., seed, feed, and manure. It not only enhances input cost but also leads to less production or crop failure. Water quality deteriorates (high BOD and ammonia levels) because of overstocking, overfeeding, and over manuring. Further, ammonia toxicity increases with an increase in temperature and pH, leading to stress & subsequently disease outbreak or mortality. Under such conditions, keep the ponds well-aerated, add common salt & apply gypsum/alum as per expert advice.
Dr. Meera also advised the farmers to follow the suggested prophylactic measures with lime (50-100 kg/acre, if pH< 8.0), potassium permanganate/KMnO4 (1-2 kg/acre) or ‘CIFAX’ (400 ml/acre) to maintain health of fishes and take care of recommended biosecurity measures to check entry of harmful pathogen. In case of any disease, immediately consult an expert for proper diagnosis and treatment.
