Study On Optimization Of The Cage For Flatfish Farming

Flatfish farming is an important part in our country aquaculture industry forproviding high-quality protein. With the decline in capture fisheries, aquaculture hasplayed a positive role to meet the demand for aquatic products. As factory farmingpresence lots of shortcomings such as high energy consumption, high cost inadequateenvironmental protection, so efficient and environmental cage aquaculture developedrapidly especially in the past three decades. Fisheries in developed countries of theworld, such as Japan, Norway, the United States, South Korea, Spain and othercountries have carried out flatfish cage culture. China also continued to promote thedevelopment of flatfish cage culture industry.Flatfish farming has a characteristics of high output and high-risk. As the carrier offlatfishes, cage must be able to provide adequate security and comfortable environment.Once the fish escape from the cages will cause serious losses. Sea cage culture are farfrom land and affected by waves and currents greatly, so stability and adequate waterexchange cages are closely related to the healthy growth fish. Therefore, it isparticularly important to optimize the performance of flatfish cages. Submersible cagesin serial used for flatfish was researched by many domestic experts and scholars. Alsothey study on the netting flow field and have made great achievements. But for theentire flow field distribution inside the cage and composition of netting cage are rarelyinvolved.This paper mainly have studied the optimization of the cage for flatfish from threeaspects f:(a) different types of cages at different velocity hydrodynamic experiments,then they compare the distribution of the flow field and analyze the ability of reducingflow for each cage.(b) they do five combination of different kinds of net with differentmash size, then measure the fixed flow rate and filtrate the best combination.(c) avariety of netting antifoulants tests and screening the best antifoulants.During the hydrodynamic test, there are eight models. The shape of the cageselected square and round. The netting mesh shape are square and diamond. The meshsize is divided into two kinds of4cm and1cm. Thus, there are eight models in totalwith different shapes of the cage, the netting, mesh size. In the test, ADV and PIVtechnology were used to measure the fixed flow rate and flow field. The test resultsprove that round cage with diamond mesh netting is the best one of high reduction ratefor the flow. The small mesh netting were severe deformation, so it should beconsidered when the cage were used.Design and experimental cages type of resistance flow were five models.4cm and1cm mesh combine together with different proportions. The combination of nettingheight dimensions are:15cm+15cm,18cm+12cm,20cm+10cm,22cm+8cm,25cm+5cm. Comparative effects of five kinds of resistance to flow cage, the results showsthat20cm+10cm do the best work.Netting with harmful aufwuch does not only effects of water exchange outside thecage, but also increases the burden on the cage. And it easily lead to the cage damaged that the fish escaped from the cages and other economic losses. According toantifouling experimental hanging experiment and toxicity tests, the best antifouling canbe selected obviously. But in the test all the antifoulants are not very good, so theresearch techniques of netting antifouling also need to be further improved.