Best Practice Technical Guidelines - Summary Advice Statement for reducing impact of pelagic longline gear on seabirds
Streamer lines have been widely promoted to deter seabirds in pelagic longline fisheries since the 1990s. However, recent evidence shows that streamer lines of either conventional or 'light' design, used in either single or double configuration, are inadequate for reducing seabird bycatch unless combined with other mitigation measures. To be effective they must be used with branchline weighting and, preferably, night setting.
The most effective measures to reduce incidental take of seabirds in pelagic longline fisheries are:
use of an appropriate line weighting regime to reduce the time baited hooks are near or on the surface and thus available to birds;
avoiding peak areas and periods of seabird foraging activity;
setting at night; and
actively deterring birds from baited hooks by means of bird scaring lines, in combination with appropriate line weighting.
Responsible management of offal and discards can also assist.
It is important to note that there is no single solution to reduce or avoid incidental mortality of seabirds in pelagic longline fisheries, and that the most effective approach is to use the above measures in combination.
The incidental mortality of seabirds, mostly albatrosses and petrels, in longline fisheries has been of growing global concern. This was a major reason for the establishment of the Agreement on the Conservation of Albatrosses and Petrels (ACAP). A large number of mitigation methods to reduce and eliminate seabird bycatch has been developed and tested over the last 10 to 15 years, especially for pelagic longline fisheries. Although most mitigation measures will be broadly applicable, the feasibility, design and effectiveness of some measures will be influenced by the type of longlining method and gear configuration used. In particular it should be noted that most scientific literature relates to fleets of larger vessels, with longline usage from artisanal fleets receiving less attention. Some of this advice may need to be modified for smaller vessels. ACAP has comprehensively reviewed the scientific literature dealing with seabird bycatch mitigation in pelagic fisheries and this document is a distillation of the review (Annex 6).
Best practice mitigation measures for pelagic longline fisheries are provided; the first recommendation is a general measure followed by those for line setting and line hauling.