New study reveals whale sharks use man-made structures to navigate oceans

whale sharks (Rhincodon typus), the largest fish in the world, are known for their great migrations across the oceans in search of food-rich environments. Of course, we know that they often follow plankton blooms, fish spawning events, or seasonal changes in water temperature. But a recent study led by scientists from the Australian Institute of Marine Science and the University of Western Australia has found that these gentle giants are attracted to both natural underwater features such as seamounts and canyons, as well as man-made structures such as oil rigs. and offshore gas. . These features, whether natural or man-made, provide critical foraging opportunities by increasing the availability of prey in the surrounding waters.

The study analyzed satellite tracking data from 78 whale sharks tagged over 14 years at Ningaloo Reef and Shark Bay, two known aggregation sites off the coast of Western Australia. “We mapped their movements across the eastern Indian Ocean and the Northwest Shelf. The latter area in particular contains a number of oil and gas platforms and associated infrastructure,” lead author Ben D’Antonio, a PhD candidate from the AIMS@UWA program, said in a press release. The data revealed that whale sharks tend to follow pathways that connect key food bases, with seamounts and industrial infrastructure acting as stepping stones along their journey. Ocean currents surrounding underwater pinnacles and seamounts increase the availability of food resources such as plankton. Interestingly, the same phenomenon appears to occur around oil and gas platforms, where artificial lights can attract plankton, creating similar feeding opportunities. While natural features can extend for tens of kilometers, the relatively small platforms seem to offer a comparable level of attraction for these massive filter feeders.

The study’s findings may have important implications for the future management of offshore oil and gas infrastructure. As platforms reach the end of their operational lives, their removal can disrupt migration patterns. “Removing platforms at the end of their productive lives can change the connectivity of the seascape by removing migratory stepping stones that connect important whale shark habitats,” he said. “There is still a need to understand the details in the relationship between whale sharks and individual oil and gas rigs, such as how often and for how long they visit.” The team emphasized the importance of considering natural and man-made features when planning conservation strategies such as Marine Protected Areas.

However, the presence of industrial infrastructure is not without risks for whale sharks. Co-author Dr Luciana Ferreira of AIMS said: “There are records of fatal interactions between whale sharks and ships and a significant proportion of the whale shark population at Ningaloo Reef have injuries attributable to ship strikes.” Moreover, she argues, the artificial presence of oil rigs can inadvertently alter natural migration routes and disrupt connectivity between key feeding and breeding grounds. “Having said that, whale sharks are at risk across large areas of their distribution from vessel strikes and fishing and entanglement, and we need to do more research to better understand the threats.”

The research was carried out with the support of several institutions, including the Australian National University, ECOCEAN, the University of Queensland and Murdoch University, with funding provided by Santos Ltd and AIMS.