Pre and Post Monsoon Management in Fish Culture

Proper and healthy growth of fish requires adequate supervision, continuous monitoring and management. Timely renovation, stocking of proper size of fish seed, species ratio and stocking number govern the growth rate of fish culture in pre and post monsoon months.

To maintain the proper fish growth, role of adequate management is crucial. Timely renovation, stocking of proper size of fish seed, species ratio and stocking number govern the growth rate of fish. Monitoring of physiyo-chemical parameter of water and soil guides for the application of organic and inorganic fertilizer and lime in pond also helpful to counteract any chance of disease outbreak in fish. Overall management controls the input extravagancy and increase the output in terms of income.

Fish culture like agriculture involves judicious management to rear the fish in pond. Management under fish farming includes pre-stocking and post-stocking management, which depends on the season/weather condition to minimize the inevitable risk. Fish species to stock, pond repair, species combination and inorganic and organic fertilizer application in pond and supplementary fish feed to cop-up the growth stradding throughout the year. Pre-stocking and post-stocking management can be divided into following:

• Pre-monsoon management

  • Pond evacuation/cleaning
  • Pond/bundh repair
  • Maintenance of water supply

• Post-monsoon management

  • To ensure fish seed availability
  • Supplementary fish feed
  • Organic/inorganic fertilizer
  • Water supply

• Post-stocking management

  • Regular monitoring
  • Feed supply
  • Water supply
  • Sampling proper

Pre-monsoon management renovation:

Before renovation of fish pond, evacuation of pond is must, so harvesting of fish through dewatering to complete harvesting should preferred. After complete harvesting draining is done. Pond remains vacated for sometimes to sun drying because for sun drying lifecycle of host fish pathogen is broken. To maintain high and stable yield, renovation should undergo following steps:

• Shallow pond should dug up to deeper pond up to 2 m depth, to increase water volume per unit area which creates a favorable condition for composite culture of different species.
• In order to prevent any damage during rainy season, repair the pond dykes, make them in a proper slope and width should be maintained to integrate with agriculture or livestock.
• Desilting: In due course of time organic matter and silt deposited on the bottom of the pond. The silt causes damage of fish gill during turbidity. This bottom silt need to be removed and can be used for agricultural crops. Repair of bundh dykes crest and water supply are necessary for routine smoothening practices. Pond cleaning should be done through deweeding/uprooting of weeds because they put obnoxious effect in water body through making imbalance in oxygen budget of pond.

Stocking management

• Pond preparation
• Water supply
• Use of lime
• Use of organic/inorganic manuring
• Fish seed availability
• Supplementary feed

Water supply

Water supply should be ensured properly prior to stocking. The dissolved oxygen and free oxygen, free carbon di-oxide are essential repository gasses which should be in right proportion to support the metabolic requirements of the fish. Water level in the pond through out the year should be in between 1.25-1.50m.

Fish seed availability

Before stocking, fish farmers should ensure the fish seed availability at hatchery for proper stocking.

Seed stocking

At each level of food chain considerable amount of original energy is lost during transfer. That is why to minimize the energy loss, proper stocking of species combination is a must. During stocking, a mixture of plankton, phytoplankton feeder, zooplanktophagus, macrophytes and omnivorous fish species are stocked. Surface feeder: Catla and Silver carp and bottom feeder: Nain and Common carp should take into consideration for stocking to utilize the natural fish food available in pond at each level.

Liming and manuring

Application of lime and organic and inorganic fertilizer in pond water is must to enhance the rate of fish production through development of natural fish food organism viz. phytoplankton and zooplankton. Lime in water gives multiple effects such as disinfectant, supply calcium into water and fertilizer. Buffering action of lime is a boon to fish culture which maintains the pH under control and provides a healthy environment to fish, that is why liming of pond is highly desirable. The dose of lime depends on the soil quality viz. soil pH which is given in Table 4.

Dose of organic and inorganic fertilizer is decided on organic carbon content present and soil quality 'high' 'medium' and 'low' criteria of the soil.

The application of phosphate and nitrogen fertilizers may be so that the phosphate and total dissolved inorganic nitrogen contents of water do not exceed 0.25 and 1.00 PPM respectively. Application of fertilizer should resorted to only in specified circumstances where there is a real need to boost production of plankton and must be based on chemical analysis of soil and water of the pond.

Depending upon the level of organic carbon in the soil, the amount of cow dung should be adjusted. Proper mode, sequence and timing are important to get good results. Lime should be applied first then the organic manure, followed by inorganic fertilizers. These fertilizers should be applied only when other physical conditions of water are most suitable such as plenty of sunlight, oxygen, optimum temperature, adequate water level and not much wind. The desired total doses of fertilizers are best applied in small periodical installments to ensure maximum utilization. The oxygen budget of the medium of organic manuring should be taken in to account. The quality of manure to be applied also depends on the organic carbon content of the soil as well as on the organic carbon of the soil.

Management practices

• Regular monitoring of water level and water level and water quality.
• Adequate supply of supplementary feed to fish for proper growth.
• Periodical netting to check the fish health and growth.
• Maintain input-output register for cost-benefit in fish culture.
• Give preference to periodical harvesting to promote the fish growth and harvest the fish as cash crop.
• Do not store the feed for longer period.
• Avoid excess and low feeding to fish.
• Do not keep the gap in feeding.
• Apply organic and inorganic fertilizer to maintain the natural food in the pond as per needs.

Reference: Singh, C. P; Kumar, Anup, Singh, R. N; and Danish, M (2011). "Pre and Post Monsoon Management in Fish Culture"