A New, Sustainable Solution for Managing Seal Predation on Fish Farms: The Targeted Acoustic Startle Technology (TAST)

Many fish farmers use high-power acoustic deterrent or harassment devices (ADDs & AHDs) to keep seals away from their fish. However, there are several disadvantages to these devices:

Genus Wave
  • These devices cause pain to the seals by emitting sound at very high source levels and duty cycles (i.e. the time that sound is produced)1
  • These devices do not provide long-term success. Seals become habituated to the devices, so they gradually stop responding to the signal.
  • These devices create a conservation problem, since they cause extreme habitat exclusion in non-target species (harbour porpoises, dolphins, and other animal species that do not pose a direct threat to the fish). 1
  • These devices can cause permanent hearing damage to the target species (seals) and to non-target species (porpoises, dolphins, etc.).

There is a new alternative that can help fish farmers keep seals away from their fish. This new solution activates the acoustic startle reflex in the seals, and addresses concerns raised by the ADD and AHD devices:

  • This approach eliminates the pain to the seals from conventional ADDs because it does not use aversive sounds to deter target animals rather it triggers an animals flight response and conditions the animal to avoid the area (like a dog whistle, but in reverse).
  • Eliminates widespread noise pollution because it only requires low noises, by using short, isolated sound signals at very low duty cycles (~1%).
  • Experimental studies have shown that repeated activation of the startle reflex provides long-term success. The seals avoided approaching the fish without the habituation effect; most seals did not stop responding to the deterrent.
  • This approach does not harm other species. Seals are specifically targeted by choosing a sound frequency to which they are highly sensitive, but to which other species are not sensitive. 4
  • This method successfully keeps seals away from a fish farm, but it does not negatively affect the behaviour and distribution of harbour porpoise. 4
  • There is no risk of hearing damage in target species (seals) or non-target species (harbour tortoises, dolphins, etc.) because this device uses much lower noise doses than regular ADDs.4

This method works! Studies conducted in Argyle showed 91-97% less seal predation over one year when using the startle-reflex system.

A prototype of the targeted acoustic startle technology (TAST) has been used experimentally in an industrial setting, and is now in production (www.Genuswave.com). TAST has recently been granted a variance request by a leading industry body, the Aquaculture Stewardship Council (ASC) which now permits its use on their certified farms. The ASC accepted TAST as a sustainable predator management tool that ‘…promotes both environmental protection and healthy fish’

References

1 Götz, T. & Janik, V. M. (2013). Acoustic Deterrent Devices to Prevent Pinniped Depredation Efficiency, Conservation Concerns and Possible Solutions. Marine Ecology Progress Series. 492, 285–302. https://doi.org/10.3354/meps10482

2 Götz, T. & Janik, V. M. (2010). Aversiveness of Sounds in Phocid Seals: Psycho-Physiological Factors, Learning Processes and Motivation. Journal of Experimental Biology. 213, 1536-48. doi: 10.1242/jeb.035535 https://jeb.biologists.org/content/213/9/1536.long

3 Götz, T., & Janik, V.M. (2011). Repeated elicitation of the acoustic startle reflex leads to sensitisation in subsequent avoidance behaviour and induces fear conditioning. BMC Neuroscience, 12(1). doi: 10.1186/1471-2202-12-30 https://doi.org/10.1186/1471-2202-12-30.

4 Götz, T., & Janik, V.M. (2015). Target-specific acoustic predator deterrence in the marine environment. Animal Conservation, 18(1), 102-111. https://doi.org/10.1111/acv.12141

5 Götz, T & Janik, V. M. (2016). Non-lethal management of carnivore predation: long-term tests with a startle reflex-based deterrence system on a fish farm. Animal Conservation, 19(3), 212-221. https://doi.org/10.1111/acv.12248

6 ASC https://asc-portal.force.com/interpret/s/article/VR334-Salmon-v-1-2-2-5-1