Preliminary Study On Principle And Technology Of Efficient Automatic Jellyfish Fishing

Rhopilema esculentum, Rhopilema hispidum, Lobomema smthi, Lobonemoidesgracilis, etc. these jellyfishes belong to edible jellyfish which are the traditionalfishing object of China. They are special sea food with nutritious characteristics anddelicious crispy tastes. Furthermore, the most mentionable one is that they have veryhigh medicinal value. It has a long history for the Chinese people who take sometypes of jellyfish as a kind of food. The earliest records can be traced back to the Jindynasty. The economic output of jellyfish plays an important part in Chinese fisheryoutput, especially in the summer fishing moratorium, jellyfish can be as the mainfishing species. The current situation of the jellyfish fishing and production methodare still sheer and primitive manual operation which consumes an enormous amountof time and resource. Meanwhile, fishing jellyfish is very hard. Moreover, theorganization of jellyfish has particularity which means the water content of jellyfish’sorganization is more than95%. In other words, although the jellyfish fishing yield ofsingle voyage is higher than other species, the fishing boat also carry back muchworthless water at the same time. So, the actual profit of jellyfish fishing are not veryhigh. The efficiency of this type of the manual operation mode is so low that it limitsthe development of the jellyfish fishery to the further open sea. In addition, the lowefficiency also increases the fishing cost. Therefore, the innovation of the fishingmethod has been one of the effective way to improve jellyfish fishery.It is the first time this research presents a theory around a kind of automaticfishing machine. First, the machine will cut each jellyfish into strips automaticallyunder the water and then pump these strips up directly. The whole innovativeproduction technology makes the entire productive process can be automated. Therelevant prototype machine has been developed successfully. In addition, it has beentested by carrying out the pilot projects on the sea and the result is perfect. The designof the underwater automatic cutting device can cut the jellyfish into strips with thelength between4.36cm to20.36cm, means12.36±4cm. Based on the actual requirement of jellyfish fishery production, this research presents operational factorsof the tailor-made jellyfish pump which is according to the design theory ofcentrifugal pump. Through the process of analysing the theory of centrifugal pumpwith a series of calculation and demonstration, the final design parameters areoptimized and confirmed.Moreover, this research design a system which can separate the collection ofjellyfish strips and the removal of sea water. This system combines the underwaterautomatic cutting equipment and the jellyfish strips pump can be assembled to form aset of equipment of jellyfish automatic fishing production. Using this equipment forthe trial production on the sea and the result have showed that the length of theNemopilema nomurai strips are between4.36cm to12.36cm, and the yield reached12.9t/h. The jellyfish strips by automatic fishing could be comparable with the ready-to-eat jellyfish goods in market. The fishing and production efficiency is25.8timesthan the hand-made fishing productivity under the same operation time. It shows thatthis equipment has greatly improved the efficiency of jellyfish fishing. Furthermore,in terms of specifications, there is not much difference between the instant jellyfishcommodities which can be bought in the market and the strips which are pumped bythe equipment. Therefore, the jellyfish automatic fishing technology and equipmentcan completely meet the requirements of the subsequent process cycle of jellyfishfishing and production. This device has a good market prospect.Furthermore, this efficient automatic fishing equipment can also be used forcleaning and preventing the disaster jellyfish bloom. It has the advantages ofconvenience and saving-time which can be regarded as a effective device to be usedfor controlling the jellyfish bloom which lead the sea water cooling pipe clogging inthe Coastal Engineering.