One of South Australia’s most popular game fish, the yellowtail kingfish, has become an attraction for tourists to dive with great white sharks at Australia’s only cage-diving site.
Researchers from Flinders University’s Southern Shark Ecology Group examined the effects of berley and bait (southern bluefin tuna) used to attract white sharks on kingfish activity and body condition.
Yellowtail kingfish (Seriola lalandi) become regular residents of the Neptune Islands, spending months alongside white sharks around the cage diving boats operating near the islands of South Australia’s southern Eyre Peninsula.
The leader of the study, Dr. Thomas Clarke, from the College of Science and Engineering, said acoustic transmitters were attached to 18 yellowtail kingfish that were tracked for two years by an array of acoustic receivers at the Neptune Islands Group Marine Park.
“We found that the kingfish’s daily activity increased by 15% when using food-based attractants such as berley, and the frequency of ‘bursting behaviors’ (more than 4 m/s).2) also increased by 60%,” he said.
“However, despite the increase in activity and frequency of (fast) swimming, the physiological condition (body) of the fish remains the same as healthy kingfish from control areas not exposed to tourism.”
The research concluded that the supplemental food sources provided by wildlife tourism—in the case of the South Australian shark tourism industry, southern bluefin tuna high in natural proteins and oils—may be sufficient to offset the additional costs of energy and minimize the impact of tourism on individual health and well-being.
The study highlights that the effects of providing from wildlife tourism can go beyond changes in behavior and movement, and can influence the energy “budgets” of non-focal animals through increased activity.
“Unfortunately, these non-focal species are often not represented in studies examining the impacts from wildlife tourism,” concluded Dr. Clarke.
The research was published in ICES Journal of Marine Science.
Thomas M Clarke et al, Influence of shark tourism on the activity and physiological state of a non-focal pelagic fish, ICES Journal of Marine Science (2023). DOI: 10.1093/icesjms/fsad093
Provided by Flinders University
Citation: Kingfish adapting to shark tourism, study finds (2023, July 19) retrieved 19 July 2023 from https://phys.org/news/2023-07-kingfish-shark-tourism.html
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