Humpback whales are returning to American Samoa!
Whales can be seen in the waters around American Samoa from about mid July to November, though dates of arrival can vary from year to year.
These long-distance migrants are arriving in our waters from feeding grounds in the Antarctic. They spend winters in the warm waters of the South Pacific. Amazingly, they do not feed here at all while they are here, but instead spend their time mating and giving birth.
You might see them from land at any point on the island that has a view of the ocean, especially sites on the western side like Sliding Rock.
Mothers, especially, can spend time very close to shore with their young calves.
Humpback whales can be individually-identified from their natural markings, especially on the underside of their tails.
The pattern on the tail is unique to a humpback whale in the same way that our fingerprints are to us. Humpbacks are studied at American Samoa based on these markings, as well as from genetics and recordings of the song that males use as a breeding ground display.
This research has been conducted since 2003, led scientists from the Center for Coastal Studies (Provincetown, Massachusetts) and the American Samoa Department of Marine and Wildlife Resources.
Past project partners on the island have included the U.S. National Marine Sanctuary Program and the U.S. National Park Service.
Researchers work under special permits required by both American Samoa and the United States for approaching marine mammals.
American Samoa is a relatively low-density breeding site, with fewer than ten whales typically seen on most days at the peak of the season.
However, through long-term research we know that nearly 400 individuals have visited Tutuila at least once over the past 15 years.
American Samoa even appears to be one of the favored destination for humpback whales in the South Pacific.
However, there is exchange with other areas and our whales can have been seen as close as Samoa and as far away as New Caledonia, Tonga, the Cook Islands, French Polynesia and Colombia.
Some of our whales pass the Kermadec Islands on their southbound migration to the Antarctic each spring.
Two whales studied at American Samoa once held a scientific record for the longest distance movement by a mammal by migrating to remote feeding grounds off the Antarctic Peninsula (18,840 km round-trip, spanning 108 longitudinal degrees).
Although humpback whales that we see at American Samoa have recently been removed from the Endangered Species List, the population is still recovering from historic whaling.
Whales face threats from a range of modern human activities, including entanglement in fishing gear and vessel strikes. A more surprising threat to humpback whales in our waters is climate change.
Scientists have recently found that the waters around Tutuila are quite warm for a humpback whale breeding ground, and they predict that increasing water temperatures may cause these animals to shift away from our waters in the coming decades.
Thus, the more that we can reduce our impacts on the environment, the longer we may have the benefit of these amazing animals off our coast.
Written by Dr. Jooke Robbins, Director of the Humpback Whale Studies Program, Center for Coastal Studies, Provincetown, MA.