By-catch in industrial fishing is a significant cause of mortality of seabirds and is thought to be one of the main reasons for the decline of albatrosses. Of 22 species of albatross, fifteen species are threatened with extinction. The birds get hooked on lines dragged behind longline fishing vessels and drown; they also collide with cables and become entangled in the nets of trawlers. Effective mitigation methods do, however, exist. Since 2015, Namibia's hake demersal-trawl and longline fisheries have been required by law to use bird-scaring lines – colourful streamers that move and scare birds away from the back of the boat. Their use reduced the number of seabirds killed by the longline fleet from about 22,000 in 2009 to about 215 in 2018 – a reduction of more than 98 per cent. In the trawl fleet, the number of birds killed declined from about 7,000 in 2009 to about 1,500 in 2017.
From: Da Rocha, N, Oppel, S, Prince, S, Matjila, S, Shaanika, TM, Naomab, C, Yates, O, Paterson, JRB, Shimooshili, K, Frans, E, Kashava, S & Crawford, R, 2021, 'Reduction in Seabird Mortality in Namibian Fisheries following the Introduction of Bycatch Regulation', Biological Conservation, 253: 1–8, doi: 10.1016/j.biocon.2020.108915.
