Effects of shark tourism on the daily residency and movements of a non-focal pelagic teleost

Abstract

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 have largely been overlooked. This study improves our understanding of the effects of shark-cage-diving tourism on the movements and behaviours of a non-focal pelagic fish. We used acoustic tracking to determine the effects of shark-cage-diving tourism on the residency and space use of 17 yellowtail kingfish Seriola lalandi at the Neptune Islands, South Australia. We revealed that while cage-diving did not affect the overall or weekly residency and space use of kingfish, 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 operators using food-based attractants increased the average time spent at the Neptune Islands by ~27% (from 230.6 ± 6.8 to 293.8 ± 5.5 min). 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 from vessel). Our findings identify changes in the daily behaviour of kingfish at the Neptune Islands as a result of food-based attractants from shark-cage-diving, which demonstrates that non-focal large pelagic species can be affected by shark-diving tourism. These effects may lead to long-term effects on the physiological condition and energetic responses of these individuals.