Action: Use bird exclusion devices (BEDs) such as ‘Brickle curtains’ to reduce seabird mortality when hauling longlines
A study of longliners in the South Atlantic found that fewer seabirds were caught on longlines hauled under BEDs with two booms, compared to those with a single boom.
Although most birds caught as bycatch are caught as the lines are set, they may also be vulnerable when the lines are hauled in, with birds attempting to take the remaining baits or even caught fish. Bird exclusion devices (BEDs) such as ‘Brickle curtains’ hang around the hauling point and are designed to prevent birds getting to the line, which will only be visible for a short time as it reaches the boat.
Supporting evidence from individual studies
A study in 2005-8 on longline vessels near South Georgia, South Atlantic (Reid et al. 2010), found that fewer birds were caught during longline hauling operations when ‘Brickle curtains’ were used (28 birds caught by 20 vessels, 19 in a single incident where the line broke), compared to a single boom exclusion device (43 birds caught by 20 vessels). Brickle curtains consisted of two booms extending over the hauling area with streamers attached, the single boom had one or more objects suspended from it. Boats using a third exclusion device consisting of two booms and a line of purse seine buoys (with or without streamers) caught no birds over three years, but the sample size was too small for meaningful comparisons to be made.