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In situ Broadband Acoustic Measurements of Age-0 Walleye Pollock and Pointhead Flounder in Funka Bay, Hokkaido, Japan
Title: | In situ Broadband Acoustic Measurements of Age-0 Walleye Pollock and Pointhead Flounder in Funka Bay, Hokkaido, Japan |
Authors: | Hasegawa, Kohei Browse this author | Yan, Naizheng Browse this author | Mukai, Tohru Browse this author |
Keywords: | Broadband echosounder | Target strength | Acoustic discrimination |
Issue Date: | 22-Sep-2021 |
Publisher: | National Taiwan Ocean University |
Journal Title: | Journal of marine science and technology |
Volume: | 29 |
Issue: | 2 |
Start Page: | 135 |
End Page: | 145 |
Publisher DOI: | 10.51400/2709-6998.1076 |
Abstract: | Measurements of the broadband acoustic backscattering from fish should improve acoustic discrimination between species. The pulse compression processing of broadband systems can be used to measure acoustic backscattering with high range resolution and improve signal-to-noise ratio. This may increase opportunities for in situ target strength (TS) measurements, the preferred method of collecting TS data. To evaluate the availability of TS spectra for acoustic discrimination, three Simrad EK80 wideband transceivers and split-beam transducers of 70, 120, and 200 kHz were used to collect in situ frequency responses of TS from age-0 juvenile walleye pollock and pointhead flounder, a swim-bladderless flat-fish, distributed in and around Funka Bay, Hokkaido, Japan. The single echoes were extracted from backscattering data, and the TS spectra of the two species were obtained. However, processing of the broadband acoustic data is under discussion. To ensure the reliability of our data, the TS spectra of standard targets were also calculated. The measured TS spectra of the standard targets were close to the theoretical TS spectra. The individual TS spectra of two species included complex frequency response; however, the mean TS spectrum was relatively stable. The different characteristics of the frequency responses observed for the two species were in good agreement with reported observations. The results available for the acoustic discrimination were similar to the multi-frequency method, which uses two or more single frequencies. The raw TS spectra should aid in not only discriminating between species but also estimating the size of the fish. |
Type: | article |
URI: | http://hdl.handle.net/2115/82701 |
Appears in Collections: | 水産科学院・水産科学研究院 (Graduate School of Fisheries Sciences / Faculty of Fisheries Sciences) > 雑誌発表論文等 (Peer-reviewed Journal Articles, etc)
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