Oral Presentation Australian Society for Fish Biology Conference 2024

Do Electrical Shark Deterrents Attract Sharks? Assessing the risks of an emerging animal management strategy (110250)

Casey O'Connor 1 , Laura Ryan 1 , Nathan Hart 1
  1. Macquarie University, Macquarie Park, New South Wales, Australia

The consequences of shark bites on humans have prompted governments worldwide to implement lethal measures such as culling. These actions harm not only sharks but also non-targeted and endangered marine animals. Electrical shark deterrents offer a potential solution for preventing negative shark-human interactions, and therefore the need for such strategies. This technology works by emitting strong pulsed electric fields designed to overstimulate the sharks' electro-sensory organs and prompt a retreat response. Widespread use is however being hindered by several critical issues, including the concern that such pulses might mimic prey biopotentials when at a distance from the device. Though the deterrent efficacy of various pulse waveforms has been evaluated, potential attraction effects have yet to be assessed. Captive white-tip reef sharks were exposed to four low-voltage pulses which resemble the weakened gradient strength of deterrent-emitted fields. We observed for behaviours indicative of heightened foraging, curiosity, or aggression. A constant direct current pulse was the only to cause significant behavioural changes, particularly an increase in rapid shifts in swimming direction. No other pulse had any noticeable effect. Though promising, more experiments are needed to ascertain the signature characteristics which may cause some stimuli to cause animal attraction and others not to.