Study On The Characteristics Of Biological Adhesion And Protection Technology Of Nets In Zhoushan Coastal Waters

With the rise of various marine aquaculture models,how to effectively prevent and control the attached organisms on the surface of aquaculture net facilities has become a prominent problem in fishery production.At present,many existing methods for preventing and controlling attached organisms(such as cleaning and replacing net,development of new anti-pollution net facilities,etc.)have practical problems such as difficult operation,high cost.Due to the objective defects of various methods,the application of antifouling paint has always been the working direction of solving the problem of biological adhesion at the present stage.Since antifouling paints have certain selectivity and timeliness on attached organisms,there are also differences between different sea areas in attached organisms.Therefore,it is necessary to conduct specialized research on the biological attachment characteristics of specific aquaculture sea areas and to master the main species of attached orgasms and seasonal variations of sea areas.And provide the evidence for the prevention measures for the attached organisms and the selection of antifouling paints in this sea area.In this paper,the biological attachment characteristics of aquaculture sea area of Tao Hua Island in Zhou Shan were studied through the net-hanging experiment in the sea area.Considering the objective reasons such as inconvenient traffic,difficulty in sampling,limited manpower and material cost,the experiment was conducted in the summer when there was a lot of biological attachment.In order to ensure the integrity of the trial,supplementary net-hanging experiments were carried out in aquaculture sea areas of Chang Zhi Island where shares a similar conditions with Tao Hua Island.The types of attachment organisms,deposition period,degree of adhesion and distribution characteristics of attached orgasms in different water layer in this sea area were studied.The bio-adhesion characteristics of different nets material were tested.The antifouling performance of a new type of quantum biomimetic antifouling paint was tested at the same time.The following conclusions were obtained:(1)A total of seven attachment organisms were recorded in the trial,namely,hydra,skeleton shrimp,ulva,symphyocladia latiuscula,mussels,Chondria tenuissima and Balanus.The compositional structure of the attached organisms in the aquaculture area of Tao Hua Island is relatively single,and the major biological factors affecting the net are hydra and ulva.The hydra adhered from May to August,and the adhesion peak was formed at the end of May.The coverage area rate reached 98%.The ulva was attached from the middle of July.It grew rapidly and had a large quantity.It mostly adhered on the net in 0.5m water layer.The coverage area ratio is about 80%.From September to January the next year,the main types of attached organisms in the aquaculture sea area of Chang Zhi Island were hydra and Chondria tenuissima.Since the sea area had low transparency and low water temperature,the number and types of attached organisms are relatively less,and most of them are concentrated on the net in 0.5 m water layer and 2.0 m water layer,the highest coverage area rate of net was only 44%.(2)The attached organisms in the aquaculture sea area of Tao Hua Island have relatively obvious water layer distribution characteristics: from May to June,attached organisms mainly concentrated on the net in the 0.5 m water layer and the 2.5 m water layer,and the net in 4.5 m water layer attached less;After July,the attached organisms of net in 4.5 m water layer began to increase steadily.In August,it was the peak period of 4.5m water layer of attachment.And the coverage area rate was higher than the 0.5 m and 2.5m water layer.From September to January the next year,there were fewer attached organisms in the aquaculture sea area of Chang Zhi Island,and there was no significant difference in the attached biomass of net in each layer.On the whole,the amount of attachment to the net in 3.5 m layer was less than 0.5 m and 2.0 m Water layer.(3)The biological adhesion characteristics of polyethylene net,fiber net,and basalt net were studied in this experiment.It was found that the polyethylene net is most susceptible to biological attachment,and the fiber net and basalt net have relatively good anti-adhesion capabilities.(4)The new quantum biomimetic antifouling paint tested in this experiment has good antifouling ability.The effective period of the paint is about 3 months,and the use effect of polyethylene net is the best.