open access

https://hdl.handle.net/2115/68584

Comparison of the effectiveness of acoustic measurements between 2 frequencies (38 kHz, 120 kHz) for monitoring of 0+ Japanese jack mackerel, Trachurus japonicus, off the Tottori coast in the Sea of Japan

マアジ当歳魚

2018-02

日本水産工学会

水産工学

54(3)

163-172

The aim of this study was to compare the effectiveness of acoustic measurements between two frequencies (38 kHz, 120 kHz) for estimations of the distribution and abundance of 0+ Japanese jack mackerel, Trachurus japonicus, off the Tottori coast in the Sea of Japan. The vessel Tottori Maru No. 1 collected acoustic data off the coast of Tottori at frequencies of 38 and 120 kHz (KFC3000). Sampling was also conducted using a midwater trawl net and an 80-cm ring net. A sound scattering layer was found to overlay the echo of the Japanese jack mackerel when sampled at 38 kHz, presenting an inherent problem to acoustic studies at this frequency. However, signals from Japanese jack mackerel could be identified on an echogram at 120 kHz. Also, the density of one individual per m3 (n) of Japanese jack mackerel, determined using the trawl net, was positively correlated with the value of the volume backscattering strength (SV) at 120 kHz　(Mean SV120 kHz = 10 log n ? 58.01 (r = 0.68)). Therefore, it is possible to estimate the distribution and abundance of 0+ Japanese jack mackerel more accurately using 120 kHz data.

学術雑誌論文

Accepted Manuscript

0916-7617