Reducing Bycatch with Sensory Deterrents
Published:27 Nov.2022    Source:ScienceDaily
A new study has revealed the potential for sensory deterrents to reduce marine megafauna bycatch in fisheries.
Sensory deterrents are designed to provide sensory cues for marine megafauna to avert their contact with fishing gear, whilst maintaining target catch quantity and quality.There are several types of sensory technologies designed to reduce bycatch, including acoustic sound devices, using alternative bait type, using water hose or cannon for deterrent, the use of lights and magnets, and changes to standard gear colour, such as lines and nets.
Multiple technologies were found effective at reducing bycatch in some studies, yet ineffective at reducing bycatch in others. LED lights were the only technology to date found successful in trials across all marine megafauna groups. However, they had also led to increased bycatch in some seabird and elasmobranch (shark and ray) species.

Publishing their findings in the journal Reviews in Fish Biology and Fisheries, the authors argue that sensory deterrents can help reduce bycatch in some circumstances. However, variable results, caused by environmental factors and differences in species biology, make generalisations difficult. Further problems include the cost of equipment and potential for unintended broader environmental harm.Variability in study results highlights the importance that scientists and policymakers must consider all available evidence when designing bycatch reduction plans for fisheries. This study collates evidence of the use of sensory deterrents in fisheries, contributing to these decision-making processes.The study's authors conclude that it is likely multiple measures will be needed to address bycatch in most fisheries. They suggest that bycatch mitigation programmes should be made on a case-by-case basis, tailored to the needs of each fishery, species and local community needs