A seven-year research project, recently published in the international scientific journal Animal Conservation, has shown that using “scare lines” to keep birds away from trawl cables during trawl fishing can dramatically reduce seabird deaths.
The research, which monitored trawl fishers off the coast of South Africa from 2006, showed that the use of the lines resulted in a reduction of 90% in seabird deaths and 99% in albatross deaths.
Seabirds, especially albatrosses and petrels, are drawn in their thousands by the offal discarded from onboard processing factories. While they’re scavenging, they become tangled in the trawl cables and drown.
Trawlers (mainly the hake fishery) use large nets, held in the water by thick cables, to trawl the seafloor. The scare lines – a simple 30m length of strong rope with five to 10 paired lines of visible streamers attached – work by distracting and confusing the birds, keeping them away from the trawl cables.
Accidental seabird deaths during fishing pose the single biggest threat to seabird populations around the world, says co-author of the paper Dr Ross Wanless, a UCT research associate and seabird division manager and the Africa co-ordinator of the BirdLife International Marine Programme.