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Hokkaido University Collection of Scholarly and Academic Papers >
Graduate School of Fisheries Sciences / Faculty of Fisheries Sciences >
Peer-reviewed Journal Articles, etc >
Optical and acoustic camera observations of the behavior of the Kuril harbor seal Phoca vitulina stejnegeri after invading a salmon setnet
| Title: | Optical and acoustic camera observations of the behavior of the Kuril harbor seal Phoca vitulina stejnegeri after invading a salmon setnet |
| Authors: | Fujimori, Yasuzumi Browse this author →KAKEN DB | | Ochi, Yousuke Browse this author | | Yamasaki, Shintaro Browse this author | | Ito, Ryohei Browse this author | | Kobayashi, Yumi Browse this author | | Yamamoto, Jun Browse this author →KAKEN DB | | Tamaru, Osamu Browse this author | | Kuramoto, Yousuke Browse this author | | Sakurai, Yasunori Browse this author →KAKEN DB |
| Keywords: | Fishery damage | | Haul out site | | Seal-fishery conflict | | Dual-frequency identification sonar | | Top predator | | Chum salmon |
| Issue Date: | Nov-2018 |
| Publisher: | Springer |
| Journal Title: | Fisheries science |
| Volume: | 84 |
| Issue: | 6 |
| Start Page: | 953 |
| End Page: | 961 |
| Publisher DOI: | 10.1007/s12562-018-1236-z |
| Abstract: | It has previously been confirmed that Kuril harbor seals Phoca vitulina stejnegeri cause damage to the chum salmon Oncorhynchus keta setnet fishery along the east coast of Hokkaido, Japan, but the level of damage has increased markedly with the recovery of their population in recent years. In this study, we attached an optical camera (Trawl Camera) and a dual-frequency identification sonar (DIDSON) acoustic camera to a setnet to observe the behavior of seals as they invaded the setnet, and to determine the number of salmon inside the net, to help inform the development of modified fishing gear. Salmon were observed at all times during daytime with the Trawl Camera, while seals were only observed once. Observations using the DIDSON in its low-frequency mode confirmed that the behavior of seals became vigorous from around sunset to nighttime within the recording time (1530-2100 hours). Observations using the DIDSON high-frequency mode showed that the overall lengths and body widths of seals ranged from 1.0 to 1.6 m and 0.15 to 0.35 m, respectively, while their swimming speeds ranged from 0.4 to 2.6 m/s, increasing around sunset and declining into the night. These results imply that seals mainly invade the setnet from evening to nighttime to predate on salmon. |
| Rights: | The final publication is available at www.springerlink.com | | © [2018] 公益社団法人日本水産学会 | | © [2018] The Japanese Society of Fisheries Science |
| Type: | article (author version) |
| URI: | http://hdl.handle.net/2115/76034 |
| 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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Submitter: 藤森 康澄
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