Use of light streamer lines and line weighting on longline vessels and the implications for seabird bycatch

Citation
Brouwer S, Walker N, Guild R (2008) Use of light streamer lines and line weighting on longline vessels and the implications for seabird bycatch. WCPFC, Port Moresby, PNG
Abstract

This paper examines two commercial longline fishing vessel's seabird bycatch rates before and after gear was re-configured in an attempt to reduce incidental seabird capture. The data were collected using fishery observers. Both vessels were setting longlines at night and used multiple light streamer lines to deter seabirds from diving on the baited hooks during the set. Vessel 1 used three light streamer lines attached to poles of varying heights, and initially had no line weighting. Vessel 2 used two light streamer lines to deter seabirds and used line weighting to increase hook sink rates. Vessel 1 added line weighting and added long streamers to the streamer line. The result was a reduction of seabird captures from 12 captures in 12 sets to one capture in the subsequent 26 sets. The Vessel 2 used streamer lines with long streamers and a line weighting regime. This vessel caught 10 birds but 8 of which were thought to have been caught on the haul. The implications of these results are discussed and the advantages of using fishery observers on commercial longline fishing vessels as a platform for research are discussed.