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

Going beyond the effects of wildlife tourism on target species: does white shark cage-diving change the spatiotemporal distribution of silver trevally (Pseudocaranx georgianus) (#154)

Joshua D Dennis 1 , Lauren Meyer 1 2 , Thomas M Clarke 1 , Charlie Huveneers 1
  1. College of Science and Engineering, Flinders University, Adelaide, SA, Australia
  2. The Georgia Aquarium , Atlanta, Georgia

Many wildlife tourism industries use food to attract charismatic megafauna within view of the participants. While food-based attractant can impact the target species of tourism operations, there is limited understanding of its effects on the typically smaller, non-target species. At the Neptune Islands Group Marine Park, South Australia, bait and berley are used to attract white sharks (Carcharodon carcharias). Previous studies have shown that the food used by the cage-diving industry affects the behaviour and activity of the pelagic yellowtail kingfish (Seriola lalandi), but whether it also influences other teleosts, including benthic species is currently unknown. We used acoustic telemetry to monitor the position, depth, and activity of 25 silver trevally (Pseudocaranx georgianus) over 34 months in relation to the presence and location of cage-diving vessels. Our results show that weekly activity space (km2) was not affected by cage-diving operators, but trevally spent extended period close to the surface (~5 m vs. ~25 m) and increased activity (m/s) when operators were present. Weekly residency decreased from ~0.9 in summer to ~0.2 in winter months and was positively correlated with water temperature and number of days operators were present. Such changes to natural behaviours have the potential to affect health, metabolic rate, energy budget, and overall fitness of individuals. Our findings will contribute to a better understanding of the effects of wildlife tourism on non-target species and will support the ongoing management of Australia’s only white shark viewing tourism industry.