From breeding grounds to feeding stopovers: modeling the seasonal habitat use of migratory humpback whales off Peru (3–18°S Southeast Pacific)

Humpback whales migrate to tropical and subtropical regions during winter and spring to breed, returning to subpolar or polar feeding grounds in summer and autumn. However, some individuals may feed at mid- and low latitudes if prey is available. We analyzed sighting data from 26 cruise surveys (2000–2019) covering Peru’s marine ecosystem (3°–18°S) and compiled 16 feeding and one defecation event from social media and independent observers (2023–2025). We employed hierarchical Bayesian models to predict the seasonal breeding distribution and stopover feeding areas of humpback whales off the coast of Peru. Results reveal that the Peruvian marine ecosystem is a highly suitable habitat during winter and spring, between 3°S and 14°S, with many groups migrating toward low latitudes to breed. During the summer, the model predicted a coastal distribution between 6°S and 18°S, with whales recorded mainly between 14°S and 18°S. A widespread offshore distribution occurred in autumn, with scattered individuals likely migrating northward. For the first time, we present feeding stopover areas predicted at 8°S–9°S, 12°S–14°S, and 17°S–18°S in productive coastal upwelling regions during the summer and autumn seasons. Groups with calves migrate through neritic areas, compared to those without calves. Migrating whales rely on energy stored in fat reserves; however, feeding stopover areas in tropical regions can offer prey for replenishing energy before reaching high latitude foraging grounds. This study highlights the importance of understanding humpback whale seasonal habitat use and behavior, particularly during migration, and their association with high-productivity upwelling areas.