Different breeding systems of native Iranian salmon

Fish farming techniques refer to solutions that produce fish at the maximum sustainable level using different tools and methods in the form of scientific principles. The main goal of management in aquaculture production is to achieve profitability through the integration of basic breeding factors such as pool, water, environment, fish larvae, investment and labor. According to the type of tools and techniques of aquatic production, fish breeding methods are divided into four categories. Types of these methods are described here:

Extensive fish farming system:
In this method, fishes are bred at no cost or at a very low cost. In these farms, a small number of fry are released in the pond and no fertilizers or additives are used in the pond, in a way, the fish are completely dependent on the natural food in the pond. In addition, in the extensive breeding system, no scientific and technical activities are carried out in the field of fish production. As a result, only 1-2 kg of fish per cubic meter is produced annually. For example, it is possible to add fish to the pond irregularly without doing calculations and without paying attention to the breeding stage and harvest time

Small water resources with a flow of less than fifty liters per second and water storage in natural and semi-natural reservoirs, dams or earth dams and large pools for use in the agricultural sector include this situation.
Extensively upgraded fish breeding system:
In this slightly modified farm management method, fish are stocked at relatively low densities after removing weeds, weeds, and predatory fish. Also, in this breeding system, the fish are fed irregularly and the fields are fertilized sporadically. Currently, this type of breeding system is used more in rural communities. In the improved extensive breeding system, the annual production of fish is 5-12 kg/m3

In large-scale breeding of warm water aquatic species, filter aquatic species are usually used in the main composition of co-cultivation, and other cultured aquatic species that use manual food are used as a secondary composition with a very low cultivation percentage.
Semi-dense fish farming system:
In this breeding method, manual food is also used, which is more productive than the extensive method. The density of the number of fish per unit of volume in this method is higher than that of the widespread method, and in some cases, in addition to manual food, natural food from the bed pool and water tank is used. Also, in this method, earthen pools, concrete pools and pools with different artificial covers are used. Breeding systems and species are very different in this method

In the semi-dense breeding system, modification of the water body, complete control of predatory fish and weeds, medium stocking density, regular fertilization and manual feeding, partial harvesting and restocking after 3-4 months and if necessary water exchange and Oxygen supply (aeration) is done. In this situation, some modern fish breeding technologies are used under the semi-intensive breeding system

The composition and type of species depends on the condition of the reservoir bed or pool. Semi-dense breeding of warm water fish is done in earthen ponds. Therefore, special measures such as water enrichment, multi-species release or co-cultivation of carp should be considered in this type of method, but if the water change is increased in any order, the selection of species, composition and percentage of culture should be changed accordingly.
In pools covered with concrete or other artificial materials, only fish that use manual food should be used. Therefore, if the reservoir is made of soil, knowing the quantity and quality of water, the climate of the region, and the quality of the soil, it is necessary to choose the type and percentage of cultivation. According to this type of breeding system, the annual production of fish per cubic meter may reach 15 to 30 kg or even more

Intensive fish breeding system:
Fish breeding using highly advanced technologies after creating expensive infrastructure is known as intensive breeding system. This breeding system requires high investment and careful work.
In this method, fish are raised in concrete and polyethylene pools and other artificial materials, and feeding is done manually, and due to the low amount of water in the water sources, the breeding in this activity is completely mechanized and the water is circulated. Although the intensive breeding system is very profitable, it is associated with a high risk, for example, the potential negative impact on the environment can be mentioned.
The rate of fish production in this system can be exploited up to more than one hundred kilograms per cubic meter according to different types of fish such as tilapia