Flow-driven patterns of whale shark movement in the Red Sea

Dynamic ocean features (e.g., currents, eddies) can drive large-scale transport of water masses and nutrients, facilitating localized plankton blooms and affecting the migration patterns of higher trophic levels. The whale shark, Rhincodon typus, is a highly migratory planktivore known to aggregate in areas of ephemeral food abundance. While the species’ presence has been widely correlated with environmental variables such as water temperature and chlorophyll-a, the Red Sea population appears to be primarily associated with other oceanographic variables. Here, we investigated factors influencing juvenile whale shark presence within the Red Sea by correlating previously published tracking data with remote sensing measurements of environmental variables using Generalized Additive Mixed Models (GAMM). Model results revealed a significant correlation between whale shark presence and mixed-layer depth, wind direction, north-south current velocity, and temperature. The model trends and satellite-tracking analysis also indicated that whale sharks would spend more time actively following eddies within the basin. This new insight can help understand how whale sharks rely on ocean dynamics in this nutrient-poor subtropical basin, as regions influenced by wind, chlorophyll enrichment, and vertical mixing offer increased foraging opportunities for the species. It may also serve as a reference point for future research that identifies key whale shark habitats and considers the impact of climate change on preferred environments.