A study undertaken over a 14-year time span has unveiled how whale shark migration is influenced by underwater topography. Researchers from the Australian Institute of Marine Science and The University of Western Australia analyzed satellite tracking data from 78 whale sharks tagged off Western Australia’s coast, revealing previously unknown migration patterns.
The study found that seamounts, canyons, and pinnacles serve as critical waypoints during long-distance migrations. These underwater structures concentrate plankton and prey, creating reliable feeding grounds for whale sharks. This effect, known as the "island mass effect," helps the sharks conserve energy during vast oceanic crossings.
Importantly, these natural features are not just random stops but function as an interconnected network of feeding stations. Seamounts, in particular, were found to have the strongest impact on habitat connectivity, suggesting that these formations may serve as natural navigational aids through their magnetic signatures or distinct environmental conditions.
Surprisingly, offshore oil and gas platforms appear to mimic the role of natural features in attracting whale sharks. Although much smaller than seamounts, these artificial structures create localized feeding opportunities through mechanisms like:
However, the interaction between whale sharks and offshore platforms introduces new risks. Increased service vessel traffic raises the likelihood of ship strikes, with many Ningaloo Reef whale sharks already showing scars from vessel collisions. Additionally, these sharks may be exposed to pollutants from operational discharges and produced water near these structures.
The study suggests that oil and gas platforms might be creating new ecological corridors, potentially altering historical migration routes. While these artificial corridors could enhance connectivity between natural feeding grounds, they also risk disrupting long-established movement patterns evolved over millions of years.
The findings raise critical conservation questions as the energy industry faces decisions about decommissioning aging offshore platforms. Many of these artificial structures have inadvertently become stepping stones between natural whale shark habitats. Removing them could disrupt migration routes, affecting not just whale sharks but also other marine megafauna.
This highlights the need to reevaluate marine conservation strategies and consider "rigs-to-reefs" programs, which convert decommissioned platforms into permanent artificial reefs. By incorporating both natural and artificial structures into marine protected areas (MPAs), conservation efforts can better support seascape connectivity and sustainable ocean development.
Further research is urgently needed to determine how frequently whale sharks visit offshore platforms, how long they stay, and the long-term ecological impacts of these interactions. With marine biodiversity conservation at stake, balancing the benefits of artificial reef creation against the risks to endangered whale sharks will be crucial in shaping sustainable ocean development.
