By Kevin Heath
A $200 device that can be fitted to trawlers has been demonstrated to reduce albatross by-catch deaths by 95% and scientists are now calling for the devices to be made mandatory. The bird scarring lines also reduce by-catch deaths of other birds by between 73% and 95% during the winter months.
A research paper published in Animal Conservation show how successful a simple bird-scaring line attached to trawlers can be to prevent birds from becoming entangled in nets and cables. The study used data collected from trawl fisheries in the South African deep-water hake trawl fishery.
In 2004, 9300 birds died in the fishery including 7,200 albatrosses. The researchers then studied the by-catch of trawlers fitted with the single deterrent of bird-scaring lines during the years 2006 – 2010. If the fitting of bird-scarring lines were mandatory the research estimated that 990 sea birds would have been killed with 83 albatrosses killed.
The bird-scarring lines were particularly effective with albatrosses – in by-catch of unfitted trawlers albatrosses made up the majority if killed sea birds while in trawlers fitted with the line the percentage of by-catch being albatrosses’ dropped to 22%.
Albatrosses are the most threatened group of birds on earth, with fishery-related deaths being the biggest threat to this group. Due to the many months they spend at sea at a time, Albatrosses produce few off-spring, meaning that these deaths have a disproportionately damaging impact on the global population.
The sea birds are most at risk during the winter when nets are being set and bait being laid.
Paper reference: Maree, B. A., Wanless, R. M., Fairweather, T. P., Sullivan, B. J. and Yates, O. (2014), Significant reductions in mortality of threatened seabirds in a South African trawl fishery. Animal Conservation. doi: 10.1111/acv.12126