Impact Of Water Refreshment Rate On Turbot (Scophthalmus Maximus) Recirculating Aquaculture And Its Economy

As one of the most important operating parameters of turbot (Scophthalmus maximus) RAS (recirculating aquaculture system), water refreshment rate impacts on turbot growth and water quality significantly, also affects the cost and profit of turbot aquaculture directly, but there are few studies about the water refreshment rate of turbot recirculating aquaculture now. The thesis studied the effect of different water refreshment rates on turbot growth and water quality by field experiment, founded the basic mathematical relationships between the water refreshment rate and the breeding cycle, FCR (feed conversion ratio), cost or profit based on the experiment, then tried to optimize water refreshment rate in the actual aquaculture farm. Main conclusions were as follows,(1)Through the experiment on site and survey, we had a comprehensive understanding of RAS and its production management, found that the RAS has high resource efficiency, little environmental pollution, good product quality and safety, and it is the inevitable choice of achieving sustainable development of marine aquaculture in the future.(2)The result of breeding experiment showed that, when water refreshment rate increased, the turbot growth rate speeded up, the feed efficiency increased, the concentration of TAN (total ammonia nitrogen) and nitrite nitrogen reduced and the water quality optimized significantly. Therefore, increase water refreshment rate has positive significance to improve the situation of the actual production of turbot.(3)Predicted breeding cycle and FCR of turbot by experimental data and existing studies, used Origin8.0 to fitting the predicted results and founded the basic mathematical relationships between the water refreshment rate and the breeding cycle and FCR. Made a further study about cost components of turbot recirculating aquaculture and derived the mathematical relationships between the water refreshment rate and the cost and profit.(4) Authenticated the mathematical relationships that have been founded by on site survey of two turbot aquaculture companies, General Aquaculture Co., Ltd and Samuels Industrial & Commercial Co., Ltd. Results showed that the mathematical relationships is consistent well with production conditions, reflects the actual variations basically and can guide the choice of water refreshment rate. Then, we provided some proposals of optimizing water refreshment rate for the two companies.The dissertation studied the basic mathematical relationships between the water refreshment rate and the breeding cycle, FCR, cost or profit. It can provide a reference to the choice of water refreshment rate in commercial aquaculture productions, help to improve the operation status of RAS, optimize the production management and make the business administration more sophisticated and standardized.