The alternative way of breathing will cost a level of energy lost which will slow down their growth. The dissolved oxygen in water is overused and fishes look for an alternative way of surviving through atmospheric oxygen. When the growth becomes less obvious it could be that your pond capacity can no longer support their healthy growth further.ĭepletion in the Dissolved Water Oxygen is a sign of overcrowding especially in pond system. This will help farmer to monitor closely how well his stock convert feed to flesh. It is a normal practice in fish farming to measure some sample fishes regularly so as to monitor the growth of the general stock through sampling. However the best option is to sell off your grow-out fishes after you notice drop in their feeding habit in spite of your effort to improve their water environment.įeed Conversion Ratio becomes lower due to overcrowding. At this point in time, fishes only feed to survive and not to grow. This is due to the fact that water environment condition will no longer be conducive for healthy growth. Response to feed reduces drastically as soon as your pond reaches its carriage limit. Optimum Stock Density: 11-20 Kg/1000 Liter.Oxygen Level: Medium to High (>8-9 ppm).Filtration: Clarifier (Biofilter take 3 to 6 months to become fully effective).As the biofilters become more effective (usually over 6 months) the stock level can be increased. This is the recommended starting fish stock level for a DWC system with biofilter and clarifier filtration system. To calculate Carriage Capacity for your system specifics. Optimum Stock Density: 31-40 Kg/1000 Liter.Optimum Stock Density: 21-30 Kg/1000 Liter.For example for system with the following specifications: Fish Stocking Density In Aquaponic Systems ( critical standing crop)Īquaponic Systems Carriage Capacity is dependent to its specifications. Note: The above calculation is recommended for a mono-culture system of catfish farming and to maintain water quality, each fish should not be fed above 20 g.
#Dwc how to calculate ppm plus#
Assuming your static pond water volume is 2000 meter square and you intend to produce average size of 900 grams of catfish at end of culturing season with an average mortality rate of 5 percent, and then calculation can be done thus:Ģ000 meter square of water volume multiplied by 1.8 divided by 900 gram plus 5 percent expected mortality rate i.e. There is more to the above calculation because we still don’t know the number of fishes to stock. Arithmetically, the calculation is simple: 2000 meter square of static pond water can carry 3,600kg of catfish. Generally, according to the recommendation of the research, a static pond system has maximum stocking capacity of 1.8kg of fish per meter square. Good! Another important thing you must predetermine before calculation begins is target size at harvest as well as expected mortality rate - usually between 5-10 percent. However, the volume of water must be known and I do hope we can all calculate water volume in any form of container based on our knowledge of elementary mathematics. The calculation was done on static water pond with depth not specified. A Simple Method to Calculate Fish Stocking Density For PondĪlthough the research was done in the USA, we can still make use of the recommendations with little or no adjustment to suit our tropical environment and African catfish that we culture in our region.