Standard Talk (15 mins) Australian Society for Fish Biology Conference 2022

King Neptune: influence of shark tourism on the behaviour and physiology of yellowtail kingfish Seriola lalandi at the Neptune Islands (#17)

Thomas M Clarke 1 , Sasha K Whitmarsh 2 , Charlie Huveneers 1
  1. Flinders University, Bedford Park, SA, Australia
  2. Marine Mapping Group, School of Life and Environmental Sciences, Deakin University, Warrambool, Vic, Australia

Marine wildlife tourism is increasing in popularity, with operations targeting a wide range of taxa globally. While previous studies have mostly focused on assessing the effects of provisioning from tourism on focal species, non-focal species that unintentionally feed on supplemental food sources are often overlooked. We used acoustic tracking to determine the effects of shark cage-diving tourism on the behaviours (residency, space use) and physiology (activity, body condition) of 18 yellowtail kingfish (Seriola lalandi) around a cage-diving site at the Neptune Islands, South Australia. We revealed that cage-diving did not affect the overall or weekly residency and space use of kingfish, although daily time spent at the islands and location of kingfish was influenced by the presence of operators. Acoustic attractant did not affect kingfish behaviours, but time spent at the site increased by ~27% (from 230.6 ± 6.8 to 293.8 ± 5.5 min) when food-based provisioning occurred. Kingfish were also observed closer to operators using food-based attractants (217 ± 4.82 m from vessel) compared to an acoustic attractant (412 ± 29.5 m). Kingfish activity (m/s2) was raised by 18% when operators using food-based attractants were present compared to days without provisioning, with burst-swimming events increasing by 60%. Despite increased activity and burst events, the physiological condition of kingfish (measured using bioelectrical impedance analysis) at the tourism site remained consistent with kingfish from a control site not exposed to tourism (n = 113). These findings highlight that the effects of wildlife tourism provisioning can extend beyond changes in focus species and can influence the movements and energetic condition of non-focal animals through increased activity. However, supplemental food or changes in natural foraging may be sufficient to compensate for the increased energy expenditure and lessen the effects of tourism on individual fitness and health.