基于基尔霍夫近似模型的南海大黄鱼声学目标强度研究

Research on acoustic target strength of Larimichthys crocea in South China Sea based on Kirchhoff Approximation Model

  • 摘要: 渔业声学是评估鱼类丰度和分布的重要方法,而大黄鱼 (Larimichthys crocea) 的声学评估常受限于目标强度 (Target strength, TS) 数据不足。基于此,利用基尔霍夫近似模型 (Kirchhoff approximation model) 对南海地区养殖大黄鱼的目标强度进行了测定和计算,并探究了其姿态倾角、体长 (L) 及声波频率等因素与目标强度的关系,旨在补充大黄鱼的目标强度数据,为南海渔业资源的声学评估提供科学参考。结果表明,在38、70、120和200 kHz频率下,大黄鱼的目标强度与体长间的拟合关系分别为TS=20logL−74.12、TS=20logL−74.34、TS=20logL−71.98和TS=20logL−70.01。在相同频率下,大黄鱼的目标强度随体长的增加而增大,并且在姿态倾角介于 −20°~−10° 和10°~20° 时表现出较高的目标强度,这与其体鳔夹角、运动姿态和生活习性相符。当频率超过70 kHz时,大黄鱼的目标强度随频率的上升而增加,但非线性关系。

     

    Abstract: Fisheries acoustics is as an important method for assessing fish abundance and distribution, but the acoustic assessment of Larimichthys crocea is often limited by insufficient Target strength (TS) data. Thus, we employed the Kirchhoff Approximation Model to measure and calculate the TS of cultured L. crocea in the South China Sea, and analyzed the relationship between its attitude inclination, body length (L), acoustic frequency and the target intensity, so as to supplement the target intensity data of L. crocea, and provide scientific references for the acoustic assessment of fishery resources in the South China Sea. The results show that at the frequencies of 38, 70, 120 and 200 kHz, the relationship between TS and body length can be approximated by TS=20logL−74.12, TS=20logL−74.34, TS=20logL−71.98, and TS=20logL−70.01, respectively. At the same frequencies, the TS of L. crocea increased with increasing body length, with higher values at angles of −20°−−10° and 10°−20°, aligning with their swim bladder orientation, movement posture and behavioral patterns. Moreover, when the frequency was over 70 kHz, the TS of L. crocea increased with increasing frequency but without a direct linear relationship.

     

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