Summer distribution and habitat preference of beluga whale social groups in the Eastern Beaufort Sea

In social animals, group composition can cause variations in individual needs that can influence responses to habitat trade-offs, such as predator exposure or foraging opportunities. The Eastern Beaufort Sea beluga whales (Delphinapterus leucas (Pallas, 1776)) form different group types and cover multiple habitat types in summer. This study compares the habitat preference of three beluga social group types: (1) individual belugas, (2) groups of adults, and (3) groups with at least one calf. Observations were collected during aerial surveys in July and August 2019. For each month, beluga distribution was analyzed with hier-archical generalized additive models, as a function of group type and four covariates: sea surface temperature, bathymetry, slope, and distance to the coastline. Group type, water temperature, and bathymetric features best explained beluga distri-bution. In July, groups of adults preferred the continental shelf, whereas individual belugas and groups with calves preferred the continental slope. In August, groups of adults and groups with calves were found in Amundsen Gulf at similar depths. For both months, individual belugas associated more with deeper and colder areas. The preferences often corresponded to previously published distributions of the beluga's main prey species, suggesting that foraging opportunities and size-related energy requirements strongly influence habitat use.

Automated summary

Group composition in social animals can influence individuals' responses to habitat trade-offs. This study focuses on the habitat preference of three social group types of Eastern Beaufort Sea beluga whales and identifies water temperature and bathymetric features as key factors influencing their distribution. The research found that the preferences of beluga groups often corresponded to the distributions of their main prey species, suggesting a strong influence of foraging opportunities and energy requirements on habitat use.