Branchline Weighting on Two Japanese Joint Venture Vessels Participating in the 2009 South African Tuna Fishery: A Preliminary Report

Citation
Melvin EF, Guy TJ, Rose B (2009) Branchline Weighting on Two Japanese Joint Venture Vessels Participating in the 2009 South African Tuna Fishery: A Preliminary Report
Abstract

Research was carried out aboard two tuna longline vessels, the F/V Fukuseki No. 5 and the F/V Wakashio No. 83, participating in the Japanese tuna joint venture fishery in the South Africa EEZ from August 4 to September 7, 2009. The principal objective was to compare the performance of two tori line designs: "light" tori lines with short streamers and the Alaska-Japanese line which mixes streamers that extend to the water with short streamers (see Melvin et al. 2009). A secondary objective was to introduce weighted branchlines into the fishery as a seabird bycatch mitigation measure using the safest line weighting system available. Our intention was to monitor the sink rate of weighted and unweighted branchlines to inform the distance astern that birds have access to baited hooks and require protection with a tori line. We also aimed to gauge the reaction of the fishing master and the crew to using weighted branchlines.