Ask the Experts: How is the Targeted Acoustic Startle Technology (TAST) target-specific?
Question:
How is the Targeted Acoustic Startle Technology (TAST) target-specific?
Answer:
A foundational issue with high-powered acoustic deterrent devices (ADDs) lies in their lack of target-specificity, meaning that they can have adverse impacts on non-target species. A key feature of TAST is the ability to achieve taxon-specific targeting (minimising impact on non-target species).
Target-specificity can be attained by choosing a frequency band where hearing sensitivity in pinnipeds is higher than the non-target species of concern (Götz & Janik, 2013; 2015). The method has empirically been shown to be successful in keeping seals away from a fish farm while not adversely affecting the behaviour and distribution of non-target species (such as porpoise, otter, and baleen whale) (Götz & Janik, 2015; 2016). A later study on inshore gillnet fisheries in Ireland also demonstrated that TAST caused no change in the presence of delphinids, confirming earlier results on target-specificity (Cox et al., 2024).
Conversely, the startle reflex can also be elicited in odontocetes by using a different (mid- or high-frequency) signal that falls in a frequency band where these species are more sensitive than seals (Götz et al., 2020). TAST can therefore be used in applications where odontocetes are a target species (such as reduction of bycatch in fisheries), and successful deterrence has been demonstrated in the wild (Hiley et al., 2021). In a latest series of experiments, TAST deterred orcas from purse seine nets resulting in an up to 92% reduction of surface activity in close sectors (Langstein, 2023; Tenningen et al., 2025).
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