Seasonal changes in the habitat suitability of immature white sharks (Carcharodon carcharias) driven by ocean warming

Ocean warming is redistributing marine biodiversity globally. Assessing shifts in species distributions is particularly interesting for large, highly mobile marine predators, as their movement ecology increases their propensity to respond to changing environments and move to more suitable habitats. We built multi-variable and temperature-only habitat suitability models for white sharks (Carcharodon carcharias) under historic and future climate scenarios throughout south-eastern Australian bioregions. Models used satellite tag data from 41 white sharks over 6 years (2015-2020) and associated environmental variables. Future model projections were applied using downscaled sea surface temperature to quantify changes in suitable habitat based on temperature between 2024 and 2080 under moderate (SSP2-4.5) and high (SSP5-8.5) climate change scenarios. Suitable thermal habitat for white sharks will likely shift poleward during Austral winter and spring, and equatorward in summer and autumn. By 2080, equatorial bioregions may become unsuitable year-round, while some poleward regions will likely increase in suitability by 27-38% in autumn, winter, and spring. Shifts in thermal suitability will likely alter the timing and extent of seasonal temperature-triggered equatorial migrations and may alter trophic dynamics and human-shark interactions. Our findings will help regional management prepare for ecological and safety implications of changing white shark distribution.