Comparative trials of Lumo Leads and traditional line weighting in the Brazilian pelagic longline fishery

Sliding lead weights (Lumo Lead) were tested in the Brazilian pelagic longline fishery. Four cruises were conducted in 2015. Three treatments were used to compare catches of target fish species, seabird bycatch and identify sink rates:
1) Lumo Lead 60 g at 1.0 m from the hook;
2) Lumo Lead 60 g at 3.5 m from the hook and
3) Traditional 60 g weighted swivel at 3.5 m from the hook.
There was no difference in the catch rates of target species among treatments. Eleven seabirds were caught during the experiment (five black browed albatrosses, five white chinned petrels and one great shearwater). All birds were caught at night and without torilines. One bird was caught on treatment 1 (0.11 BPUE), three birds in the treatment 2 (0.33 BPUE) and seven birds in the treatment 3 (0.85 BPUE). Lumo Leads placed at 1.0 m from the hook sank faster than Lumo Leads and weighted swivel placed at 3.5 m. The high seabird mortality rates on treatment two and three suggests that the combination of night setting and line weighting placed at 3.5 m is not enough to reduce seabird bycatch in the SW Atlantic to negligible levels.
RECOMMENDATIONS
1. SBWG note that despite the utilization of line weighting and night setting (two of three recommended mitigation measures) a high seabird bycatch rate was found on branch lines with line weights placed at 3.5 m. This reinforces the need for toriline use simultaneously with line weighting and night setting in the SW Atlantic in order to reduce seabird bycatch rates to negligible levels, or the modification of ACAP line weighting recommendations.
2. The establishment of observer programmes and/or electronic monitoring is recommended in order to ensure compliance with mitigation measures.