Longlining fishing activity can present a serious danger to seabirds. As they are attracted by the bait and the fish being hauled on board, they can get caught on the baited hooks and drown. Worldwide concern for the decline in petrel and albatross populations over the last 20 years has led to significant changes in fishing practices which are simple, cheap and can be 100% effective in avoiding seabird mortalities:
- Weights: by placing heavy weights regularly along the line, the lines sink much faster during setting operations and the seabirds have no time to target the baited hooks before they disappear beneath the surface.
- Tori lines: tori lines consist of long lines with streamers attached deployed from the stern of the vessel which are towed along behind the boat during setting. The effect of the streamers is to ring-fence the hooked longlines and so discourages the birds from attacking the line.
- Hook Removal and Disposal: ensuring that the crew are alert and properly trained in the factory to remove any hooks caught in the discards and to dispose of them properly is critical to ensure that birds are not getting hooked when feeding off the discards from the vessel.
- Brickle Curtain: a simple mechanism around the hauling area consisting of rope lines connecting poles at right-angles to the vessel, prevents birds from becoming hooked as the line is winched up from the sea-bed. The device was developed by a former employee at CFL, Paul Brickle, and is now used on vessels around the world.
Perhaps the most effective measure to mitigate seabird mortality has been the change in the fishing system used by longliners principally in Chile and the Falkland Islands. The use of “umbrellas”, devised originally to combat depredation by whales, has been wholly effective in protecting the seabirds from hooks. To see how this works see “Fishing Systems”