Fish Target Strength Measurement Model

Target scattering strength is an important research content in fisheries acoustics, and it isalso an important parameter for the marine resource acoustical surveys. The studies of targetscattering strength of fish started late in domestic. In recent years, some domestic scholars used‘wild fish observing’ method to measure the target scattering strength. The empirical formulas ofcalculating target strength of Sardine’s and Bering Strait pollock’s had been found. But the modelfish target scattering strength studies has little been reported across the nation.This experiment was made in Honkaido University Ocean Ranch Technical ResearchCenter. The size of test tank is5m×5m×5m. MFT-90and FB-8are used as acousticmeasuring instrument. The transducers’ working frequency are28kHz、50kHz and98kHz. Theresult of this experiment is basically consistent with the theoretical characteristics of the fish.Because of the density of different’ model，there are differences between model fish and real fish.Finally, give some suggestions for improving the measuring system.Fish target strength is made of fish, fish size (body length, body weight), fish (meat, bonestructure, such as fish, swim bladder) causes the movement range of gestures and so on andproduce complex changes.95%of TS is contributed by bladder. The swim bladder has exertedan important influence on the size of target strength. Based on these, the experiment used and noBiao fish and swim bladder of fish density similar simulation material, selected materials forfoamed polystyrene, silica gel, and the introduction of a reference material of metal iron, thelength were5cm,7cm,10cm, a total of9sticks, the experiment is carried out in28kHz,50kHzand98kHz, try to conclude the relationship between target strength, length, frequency andmaterial...