Linking environmental variability to seasonal individual occurrence of male sperm whales Physeter macrocephalus in the Northeast Atlantic

Seasonal variability in Arctic regions strongly shapes prey distribution, which in turn determines the spatial scale of predator-prey interactions and drives animal habitat use and foraging behaviour. Thus, using environmental factors can help in studying the ecology of male sperm whales Physeter macrocephalus living in dynamic high-latitude ecosystems. We asked how environmental variables influenced their monthly detection and emigration probabilities using multistate capture-recapture models within a Bayesian framework. We used 4 yr (2020-2023) of photo-identification data from a foraging ground in Northern Norway. Models accounted for individual heterogeneity previously described in the study area through behavioural clusters based on seasonal occurrence, site fidelity and social behaviour. Detection probabilities differed across seasons (winter: p = 0.22; summer: p = 0.35) and clusters. During winter, emigration probability (ψ1 = 0.23) was negatively affected by sea surface temperature (5-7°C) and greater Northeast Ekman transport. These variables were related to coastal upwelling, which attracted potential demersal and pelagic prey in shallower waters. During summer, emigration probability ( p = 0.62) was negatively affected by higher net primary production. This was consistent with increased pelagic prey availability over deep-water habitats such as the Bleik Canyon. Overall, our results suggest that seasonal habitat use and foraging behaviour of male sperm whales are shaped by environmentally driven shifts in prey fields. These seasonal variations were also affected by individual behavioural strategies. Our findings emphasize the importance of considering a fine-scale approach and individual heterogeneity to understand the ecology and foraging behaviour of male sperm whales in high-latitude ecosystems.