An overview of the evolution of cold water fish production in Iran and the world

Aquaponics is a combination of fish cultivation (Aquaculture) and plant cultivation (Hydroponic) in circulating systems. In this system, fish excrement, which are mainly nitrogenous compounds such as ammonia, and non-nitrogenous compounds such as phosphorus, are absorbed by the plant and removed from the water. In the aquaponics system of Valiasr University, Rafsanjan, the water from the fish breeding tank after passing through mechanical filters enters the hydroponic substrate and this substrate as a biofilter creates a suitable environment for the growth of bacteria such as Nitrozomonas and Nitrobacter, which respectively convert ammonia and nitrite of the breeding water. They do fish to nitrite and then nitrate. Some of the nitrates are used to feed the plants and the purified water in the system is re-entered into the fish breeding tank. According to the heat requirement of carp fish (20-30 degrees Celsius) and accessible water temperature, this type of tropical fish was bred. Basil and mint leafy vegetables and cucumber and tomato fruit vegetables according to the proper adaptation to the system Aquaponics were introduced. Basil, mint and tomato showed good compatibility with the aquaponic system, while cucumber dried up in the early stages of growth, probably due to the contamination of the roots with pathogenic fungi. The measurement of photosynthetic and water parameters in mint showed that the amount of photosynthesis And the efficiency of water consumption in aquaponic treatment is higher than hydroponic. In general, the results showed a better ecophysiological condition of mint plants in aquaponic system.