Humpback whales are widely known for undertaking some of the longest seasonal migrations in the animal kingdom, traveling between feeding and breeding grounds across entire ocean basins. But a small, isolated population in the Arabian Sea appears to have broken that rule entirely, according to new research published in Frontiers in Marine Science.
The group, known as Arabian Sea humpback whales (ASHW), numbers about 80 individuals living off the coast of Oman. Scientists believe they split from Southern Hemisphere humpback whales roughly 70,000 years ago and have since evolved significant genetic differences. Unlike other populations, they appear to remain in the Arabian Sea year-round, making them the only known non-migratory humpback whales.
Early evidence for this unusual behavior emerged from Soviet whaling records in the 1960s, which suggested the whales’ reproductive cycles were offset by about six months compared with Southern Hemisphere populations. That finding has now been reinforced by modern satellite tracking data.
Over several years, marine scientist Dr. Andrew Willson and an international team deployed 14 satellite tags on whales in two key locations: Masirah Bay and the Hallaniyat Islands off Oman. The tags transmitted more than 1,800 location points over an average tracking period of 53 days.
The data showed that Masirah Bay accounted for 57% of recorded transmissions, while Hallaniyat contributed 18%, suggesting both areas are critical habitat zones for the population. Researchers believe the whales’ movements are closely tied to prey availability along the coast, particularly sardines on the continental shelf, while deeper offshore dives may be linked to feeding on krill in deeper waters.
One whale, a female named Luban — identified by a distinctive tail pattern resembling incense — delivered an unexpected breakthrough in the study. Tracking data showed she crossed the Arabian Sea eastward and was later detected off the western coast of India near Goa, completing a round-trip journey of roughly 7,000 kilometers, an unprecedented movement for the population.
While whale vocalizations had previously been detected between Oman and India, Luban’s tracked journey is the first confirmed long-distance movement of an Arabian Sea humpback whale. She remained in southern Indian waters for about a month, an area known for high biological productivity that attracts large numbers of fish and predators.
Researchers believe Luban may have traveled to feed, reproduce, or potentially both before returning to Masirah Bay. Her movement, Willson said, challenges long-held assumptions about humpback whale ecology and suggests the Arabian Sea population has adapted to a dramatically different environmental system over evolutionary time.
Today, Arabian Sea humpback whales are listed as endangered and face multiple threats, including climate change-driven disruptions to upwelling systems in the Gulf of Oman, as well as human pressures such as fishing activity and ship strikes.
Aida Al Jabri of the Oman Environment Authority, who supported the research, said coastal communities in Oman have long recognized and respected the whales’ presence. Suaad Al Harthi, executive director of the Environment Society of Oman, said the Arabian Sea represents a rare ecosystem where a once-migratory species has fully adapted to a localized environment.
Researchers hope the satellite data will help guide conservation measures, including efforts to reduce fishing impacts by identifying critical habitats and migration corridors.
The study underscores a striking ecological exception in marine biology: a population of humpback whales that may have abandoned migration entirely, surviving instead within a single ocean region shaped by unique environmental conditions.
