Brady bird baffler and trawl mitigation

Brady bird baffler and trawl mitigation

The Brady bird baffler was developed by Keith Brady to reduce seabird deaths in trawl fisheries. Keith came up with the idea in 1996, after having spent time as a government observer on deep sea trawlers in New Zealand waters. He knew that birds feeding on fish scraps near the stern of the vessel risked getting killed or injured by the trawl warps - the heavy steel cables that towed the trawl gear.

Keith studied how seabirds behaved as they chased fish scraps in a trawler's wake. He observed how they dislike flying under things or having something above them and used this knowledge in developing the baffler mitigation system.

Keith developed a prototype baffler in 1999 and trialled it on the trawler Tomi Maru 86, fishing in New Zealand waters in the Southern Ocean. In developing and modifying the device, Keith was aware it needed to be tough enough to go fishing in the Southern Ocean, yet not injure seabirds if they accidentally flew into it.

Other vessels then began trialling Keith's baffler. One of these was the trawler San Waitaki. The San Waitaki is a Norwegian factory freezer trawler, built by Sterkoder. Its deck structures are higher above the water than those of the Tomi 86. San Waitaki skipper Dave Webb found the baffler needed fine-tuning to better suit his vessel.

The baffler was thought by some to be the answer to seabird mitigation in New Zealand deepwater trawl fisheries and the industry encouraged vessels across the fleet to adopt this during 2003. Most of these installations were not actually the Keith Brady bird baffler, but were individual skippers and vessel managers' interpretation of his design.

Keith Brady had hoped to protect his baffler design by taking out a patent on it.

On the other side of the Southern Ocean, in the Falkland/Malvinas Islands, fishermen and government officials wanted to address the issue of seabird deaths in their pelagic trawl fishery. They saw the Brady baffler as a possible answer and arranged some scientific experiments using this device. These experiments also included a local device (the 'Falkland Island Warp Scarer') and paired streamer lines (bird scaring) lines.

All three devices were trialled in a trawl fishery where giant petrels and black-browed albatrosses were the main issue. The Brady baffler reduced recorded deaths by around 90%, and potential injuries around 50%; while the paired streamer (bird scaring) lines showed around 100% reduction in deaths and around 98% reduction in potential injuries.

As a result of these trials, Bird Scaring Lines have become a licensing requirement for finfish and ray trawlers operating in Falkland Island waters and for all Falkland-flagged vessels on the high seas.

In 2006, New Zealand's Ministry of Fisheries arranged scientific trials comparing the effectiveness of bird bafflers, warp scarers and paired streamer (bird scaring) lines for seabird mitigation in its southern squid trawl fishery.

The study found paired streamer were the most effective of the three methods at reducing seabird strikes on trawl warps in that fishery. One disadvantage with streamer lines is that when the vessel is turning or when there are strong crosswinds, paired streamer lines often will only end up protecting one warp, leaving the other exposed.

The New Zealand government brought in legislation in early 2008 that required either bafflers, warp scarers or streamer lines to be used on all trawlers over 28-metres length.

Bafflers are still a commonly used seabird mitigation method in New Zealand's deepwater trawl fishery. This is because they are 'set-and-forget' devices. You don't have to put them out each time you set the net is set, or pull them in when the it is hauled - like a streamer line. Nor are they prone to tangling - like a warp scarer.

Some New Zealand deepwater trawlers are required by company policy to run both bafflers and paired streamer lines whenever trawling.

New Zealand trawlers fishing deep for orange roughy have adapted the baffler to completely enclose their trawl warps (fishing deep means these warps enter the water very close to the vessel).

References

Leigh S. Bull (2007) A review of methodologies for mitigating incidental catch of seabirds inNew Zealand fisheries DOC Research & Development series 263 (2007): pp 31-35.

Baffling birds brings benefits Seafood New Zealand magazine 2002 vol. 10, no. 10: pp 60-61.

Trawling for solutions Seafood New Zealand magazine 2005 vol. 13, no. 1: pp 40-41.

A history of mitigation Seafood New Zealand magazine 2009 vol. 17, no. 3: pp 16-19.

Melvin, E; Dietrich, K; Wainstein, M Solving Seabird Bycatch In Alaskan Fisheries: A Case Study In Collaborative Research Washington Sea Grant Program.

http://www.wsg.washington.edu/communications/online/seabirds/seabirdsolvinglr.pdf

Melvin, E.; Dietrich, K; Thomas, T.; (2004) Pilot tests of techniques to mitigate seabird interactions with catcher processor vessels in the Bering Sea pollock trawl fisheryWashington SeaGrant Program. University of Washington, Seattle.

B. J. Sullivan 1, 2 , P. Brickle 3, T. A. Reid1, D. G. Bone 4 and D. A. J. Middleton (2006)Mitigation of seabird mortality on factory trawlers: trials of three devices to reduce warp cable strikes Polar Biology, Volume 29, Number 9; August, 2006. pp 745-753.

http://www.springerlink.com/content/gj635661284m3883/

Middleton, D. A. J. and Abraham, E. R.; (2007) The efficacy of warp strike mitigation devices: Trials in the 2006 squid fishery. Final research report for New Zealand Ministry of Fisheries project IPA2006-02

Bull, Leigh S. (2009) New mitigation measures reducing seabird by-catch in trawl fisheries. Fish and Fisheries, Volume 10, Number 4, December 2009 , pp. 408-427(20)http://www.ingentaconnect.com/content/bsc/faf/2009/00000010/00000004/art00004;jsessionid=fbj9jlibvvco.alexandra