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Fisheries Science

, Volume 77, Issue 4, pp 479–485 | Cite as

Effectiveness of tori-lines for further reduction of incidental catch of seabirds in pelagic longline fisheries

  • Kosuke YokotaEmail author
  • Hiroshi Minami
  • Masashi Kiyota
Original Article Fisheries

Abstract

To improve the performance of tori-lines (bird-scaring lines) in reducing incidental catch of large seabirds (albatrosses and giant petrels) in the pelagic longline fishery, we analyzed factors affecting the performance of tori-lines based on data collected by Japanese scientific observers in the southern bluefin tuna Thunnus maccoyii fishery from 2002 to 2005. We classified the variety of tori-lines by the main tori-line length and the streamer type. Two types of streamers were identified: type A, several long streamers made of nylon cord attached to the main tori-line by metal swivels; type B, many short streamers made of polypropylene packing bands braided into the main tori-line. In a model analysis, we found that the main tori-line length was an important factor affecting tori-line performance, and the two types of streamers had similar effectiveness. Since the light type B streamer has the advantage of practical feasibility, this type can be another option for use in tori-lines if used with a main tori-line of sufficient length.

Keywords

Albatross Bird-scaring line Bycatch Mitigation measure Seabirds Streamer line Tuna longline Tori line 

Notes

Acknowledgments

We are grateful for the effort of scientific observers in collecting data and valuable information often under severe conditions at sea. We thank Dr. O. Sakai of National Research Institute of Far Seas Fisheries for information on the southern bluefin tuna fishery. Two anonymous reviewers provided helpful comments on a draft manuscript. The scientific observer program has been managed by Federation of Japan tuna fisheries and Japan Fisheries Resource Conservation Association. This study was conducted as a part of the Program on the International Fishery Resources Survey, Fisheries Agency, Japan.

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Copyright information

© The Japanese Society of Fisheries Science 2011

Authors and Affiliations

  1. 1.Marine Fisheries Research and Development CenterFisheries Research AgencyKanagawaJapan
  2. 2.National Research Institute of Far Seas FisheriesFisheries Research AgencyShizuokaJapan
  3. 3.National Research Institute of Far Seas FisheriesFisheries Research AgencyYokohamaJapan

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