Action: Use a sonic scarer when setting longlines to reduce seabird bycatch
Key messagesRead our guidance on Key messages before continuing
A single study from the South Atlantic found that seabird bycatch rates did not appear to be lower on longlines set with a sonic scarer, and that changes in seabird behaviour due to the scarer were only temporary.
It might be possible to stop birds from taking baits from longlines by scaring them away from boats using loud noises.
Supporting evidence from individual studies
A study on a commercial fishing boat in the South Atlantic in April-May 1994 (1) found that longlines set with a sonic scarer did not appear to catch fewer seabirds than lines set without a scarer. Lines set with and without the scarer were not analysed separately (with 15 birds caught on six sets without a scarer and six with, as well as three with a streamer line), although the authors observed changes in behaviour when a scarer was first used, but that birds quickly got used to the noise. The scarer emitted periodic bursts of compressed gas. This study is also discussed in ‘Set longlines at night to reduce seabird bycatch’ and ‘Use streamer lines to reduce seabird bycatch on longlines’.