Prediction of nitrogen levels in Huso huso (Linnaeus, 1758) culture in Pens located in the south-east of the Caspian Sea using mathematical and dynamic models.

The purpose of this research is to estimate the amount of nitrogen output resulting from raising juvenile Huso huso (Linnaeus, 1758) in the proposed pens located on the southeast coast of the Caspian Sea using the nitrogen dynamics model. In this research, nitrogen excretion was measured by storing 30,000 juvenile Huso huso in 750 square cages, the end of which was connected to the graft (pen) at a depth of 2 meters during 7 months of rearing (June to December) with an initial weight of about 30 grams and The final weight was about 750 grams at the end of the period and the average food conversion ratio was 1.5 and the percentage of survival was 82%, and the production of about 18 tons of fish was estimated. The results showed that at the end of the breeding period, it can be expected that the total amount of nitrogen and phosphorus (inorganic) entering the sea will be 0.919 and 0.123 tons, respectively. According to the dynamic model, the nitrogen discharged into the sea at 20 meters from the cage is estimated to be 0.13 mg/liter and 0.01 mg/liter at 1000 meters, which indicates compliance with the minimum radius of 100 meters from each cage to the next cage. Is.