中国水产科学2018，Vol.25Issue(2)：403-412,10.DOI:10.3724/SP.J.1118.2018.17088
多鳞(鱚)目标强度的模型法研究
Modeling study on the target strength of Sillago sihama
摘要
Abstract
Measurement of fish target strength is one of the core components of fisheries hydroacoustics. Research focused on offshore fish in the South China Sea has not met the needs of fisheries-resource estimations. As a typ-ical offshore fish, little is known about the target-strength characteristics of Sillago sihama. To understand the target-strength characteristics of S.sihama, a Kirchoff ray-mode approximation was used to calculate the theo-retical target strength of 19 S.sihama samples and the morphological parameters,calculated using a model of the fish, were obtained using an X-ray machine (SOFTEX M-100) belonging to the South China Sea Fisheries Re-search Institute, Chinese Academy of Fishery Sciences. The changes in patterns of target strength of S.sihama with tilt angle were obtained by calculating programmatically at different frequencies. The empirical formulas of target strength of S.sihama with body length were established for different frequencies and the distribution func-tion of the tilt angle was produced using a data-fitting method, and compared with the conventional b20expression. The results show that the various patterns of target strength of S.sihama,with tilt angle at 70 kHz,120 kHz,and 200 kHz, show multiple-peak-like distributions, and the variation of target strength with the tilt angle is more sen-sitive at higher frequencies. As the number of crests increased, the maximum target strength corresponding to the tilt angle increased.Maximum target strength of S.sihama occurs between–15°and 5°at 70 kHz,and the maxi-mum target strength appears between –10° to 0° at 120 kHz and 200 kHz. The position of maximum target strength occurred differently at each frequency.The varying characteristics of target strength of S.sihama with body length changed under different frequencies and distribution functions of the tilt angle. When the angle function is (–5°, 15°), frequency is 120 kHz, and when the angle function is (0°, 10°), frequency is 200 kHz, the empirical formula and the conventional b20expression curve of target strength with body length coincide, the degree of fit is higher, and the conventional b 20formula can be used directly for resource assessment of S.sihama.In other cases, there are some deviations in the two formulas, and the direct fitting parameter equation is more appropriate. The study confirms that the Kirchoff ray-mode approximation can reflect the target-strength characteristics of S.sihama, providing a useful reference for the study of target strength of inshore fish in the South China Sea and a scientific basis for improving the accuracy and credibility of hydroacoustic assessment of fisheries resources.关键词
目标强度/多鳞(鱚)/姿态倾角/基尔霍夫近似模型Key words
target strength/Sillago sihama/tilt angle/the Kirchoff ray-mode approximation分类
农业科技引用本文复制引用
李斌,陈国宝,曾雷,王志超..多鳞(鱚)目标强度的模型法研究[J].中国水产科学,2018,25(2):403-412,10.基金项目
公益性行业(农业)科研专项(201403008) （农业）
深圳市科技计划项目(JSGG20141015154342147) （JSGG20141015154342147）
农业部财政项目南海海洋捕捞生产结构调查(640). （640）
