Recirculating Aquaculture Breeding – Step Two
In a closed-circuit fish farming system, high quality feeds are beneficial because it minimizes the amount of fish waste and thus reduces its impact on the water treatment system. In an unprofessional management system, all inappropriate foods added to the feed are eaten, but the conversion rate (FCR) explains how many pounds of feed are consumed per kilo you produce, and aquatic life. The farmer should know that a higher quality feed will have a higher impact on fish growth and less impact on the return water treatment system. Inadequate nutrition is a waste of money and in addition has no effect except increasing pressure on the filtration system. It should be noted that proper nutrition is available for use in modern systems. The purpose of combining such foods is to maximize protein uptake in fish and to minimize ammonia excretion in water.
Environmental conditions in the fish breeding pool should meet the needs of the fish depending on the quality of the water and the design of the pool. Choosing the right pool design, such as size and shape, water depth, cleaning ability, etc. can have a significant impact on its performance.
If the fish are at the lowest level, the pool water level is very important and the water depth and water flow rate can be reduced (depending on the type, size or species of fish), while the fish species will benefit from a larger volume of water. And show better performance at higher water velocities.
In a round pool, or in an octagonal pool, water moves in a circular pattern that drives the entire water column around the center. Organic particles provide a relatively short residence time of a few minutes, depending on the size of the fish pond due to the hydraulic flow of water and the self-purification effect of the fish pond structure, vertical inlet adjustment is an efficient way to control water flow in such ponds.
Of course, if fish ponds are effectively stored with fish, the effect of self-purification of fish ponds with fish activity will be better and more appropriate. In designing a fish pond, the slope of the pond (depending on the species and type of fish) does not have much of an effect on waste disposal performance, but makes it easier when fully discharged.
Round or octagonal pools have a higher construction cost compared to raceways pools and take up more space than round pools. In octagonal pools, fish breeding seems to be a proper design of the octagonal pool, which results in better spatial use than the circular pools, in addition to the positive hydraulic effects of the round pool. It is important to note that in the construction of large pools, circular or octagonal pools always have better results than other structures, as this is the strongest and best design in fish pool construction.
Adequate levels of dissolved oxygen are important for the well-being of fish in fish breeding, and the amount of dissolved oxygen in the fish pond is usually maintained by increasing the level of oxygen in the inlet water. Direct injection of pure oxygen into the fish pond using a variety of aeration and diffusers can also be used, but they are less effective than pure oxygen.
Controlling and adjusting dissolved oxygen levels in round or octagonal pools is relatively easy because the water column continuously mixes dissolved oxygen mixtures almost everywhere in the fish pond. This means that maintaining the optimal oxygen level in the fish pond is very easy. An oxygen meter or water-soluble oxygen probe, which is located near the outlet of the fish pond, gives you a good indication of the soluble oxygen available. The time required to evaluate the amount of dissolved oxygen added to a round pool or octagon pool will be relatively short. This probe or oxygen meter should not be placed where pure oxygen is injected or where dissolved oxygen rich water is injected.
However, in a raceway pool, the oxygen content at the upper and lower inlets will be higher at the outlet, giving a different environment depending on where each fish swims. Oxygen meter or oxygen probe To measure the amount of dissolved oxygen in water, it must always be located at the lowest oxygen level near the outlet. Control of dissolved oxygen is usually important at the outlet and makes it more difficult to regulate dissolved oxygen because the delay in regulating dissolved oxygen at the inlet and outlet of the fish pond can take up to an hour. This may cause the dissolved oxygen to rise and fall at the selected level. Installing modern dissolved oxygen control systems using algorithms and scheduling avoids these unwanted fluctuations.
Behruz Alinia Fard
Fisheries Analyst and Complicator