seyedeh lili mohebi nozar

The possibility of algal blooms at the location of the cages and the surrounding water is one of the major risks associated with the management of fish farming in cages. In the present study, the risk of eutrophication (risk of algal blooms), the rate of nutrient enrichment (eutrophication) and the availability of nutrients (for phytoplankton consumption) due to fish farming in the waters adjacent to the cages with Farther from the location of the cages during a six-month rearing period in Qeshm region was compared. In the study, the range of changes related to scale and non-scale trophic indices and trophy efficiency coefficients were equal to 3.75-5.23, 3-4-78 and 3.78-4, respectively. Based on the studied indicators, the trophy status in the waters adjacent to the cages is high (at the mesotrophic level) and the risk of blooming is high, as well as the availability of nutrients by primary producers (phytoplankton) based on the trophy efficiency coefficient was high. However, in the waters farther from the location of the shelves (control station), the trophy status was moderate (at the mesotrophic level) and the risk of blooming and the availability of nutrients were low. The use of superior technologies and proper, principled and scientific management of water and food quality, in addition to reducing the environmental effects of such activities can play an important role in increasing production, exports and further valuation by this industry.

With the arrival of large amounts of effluent during the one period from aquaculture into coastal ecosystems, it can introduce large amounts of pollutants into coastal waters during each breeding period. A review of recent studies in the region shows that the changes in phosphate levels, total suspended solids and BOD levels in the effluents were beyond the scope of the environmental standard. The results of the organic load estimate showed that, during a breeding period, with a minimum of 5% water replacement, approximately 500 tons of soluble Dissolved inorganic nitrogen and 25,000 tons of soluble phosphate entered the Enter the waters of the Tiab estuary through effluents. Therefore, it is suggested that by creating sedimentation ponds (to reduce suspended solids), build a biological treatment system (to reduce nutrients), define environmental standards permissible limited necessary for effluents to enter coastal waters and revision the management of Shrimp farms, from any Effects and environmental risks associated with aquaculture activities in coastal ecosystems be avoided.

In this study, Given the importance of water quality management of shrimp farms, three farms (three pond per farm) in the northern Tiab area of Minab city of Hormozgan province were studied to evaluate the Environmental conditions of shrimp ponds (Litopenaeus vannamei) during a six-month period (June to December, 2014).The results showed that the ranged water temperature were (15.50C-37.40C), pH (7.1 - 8.97), salinity (41 p.p.t -59.5 p.p.t), dissolved oxygen (0.7 mg.l - 9.5 mg.l), nitrite (0.3 μm.l - 54.5 μm.l), Ammonia (0.01mg.l - 0.13mg.l) and Transparency (10 cm - 95cm) . The results of cluster analysis showed that the water quality has varied between shrimp farms together. The high water temperature and salinity of shrimp farms acts as a negative and limiting factor for shrimp production. Also the water temperature, dissolved oxygen, salinity, Transparency and chlorophyll-a were out of range (permissible limits) in shrimp farms for Litopenaeus vannamei.Avoid increasing shrimp density at surface if poor water quality management is not implemented. On the other hand, increasing the concentration of pollutants in waste water shrimp ponds can cause problems in the future for the coastal environment.