基于基尔霍夫近似模型的大眼金枪鱼目标强度估算研究OA

To accurately determine the Thunnus obesus fishery resources,acoustic methods were used and a single individual was selected and scanned using CT to obtain morphological parameters of the fish body and swim bladders.Based on the Kirchhoff approximation model,its'target strength was estimated at frequencies of 50,70,90,120,200 kHz under different tilt angles.Acoustic instruments were used to collect incidents and reflected voltage data at the same frequencies,and the actual measured target strength was obtained through formula conversion.Additionally,empirical values of target strength were calculated using high-frequency empirical formulas.A comparative analysis and statistical test of the model values,measured values,and empirical values showed that:1)At low frequencies(such as 50 and 70 kHz),the measured values had higher accuracy,and the model values were highly consistent with the measured values;2)At high frequencies(such as 120 and 200 kHz),the model values were closer to the empirical values;3)At high frequencies(≥90 kHz),the differences between the model and the measured values were mainly related to the performance characteristics of the acoustic instruments,the measurement environment,and the internal structure of the fish.This study preliminarily verified the effectiveness of the Kirchhoff approximation model in estimating the target strength of T.obesus,providing a reference for fishery resource acoustic assessment research.