NOAA Research Discovers Wintering Humpback Whales in the Northwestern Hawaiian Islands

photo of humpback whale
Humpback whales engage in competitive group behavior in the Northwestern Hawaiian Islands.
Photo by Marie Chapla, PIFSC

Every winter, many humpback whales in the North Pacific make lengthy migrations from their feeding grounds near Alaska to breed in the warm waters of Hawaii - and it now appears they have a greater range of vacation destinations available than previously realized. New findings published on September 20, 2007 in the peer-reviewed journal Endangered Species Research reveal that some humpbacks spend their winters in the Northwestern Hawaiian Islands in the protected waters of the Papahānaumokuākea Marine National Monument.

Whale researchers from NOAA's Pacific Islands Fisheries Science Center have discovered that endangered humpback whales - once severely depleted by commercial whalers in the North Pacific but now on the road to recovery - are using part of the Northwestern Hawaiian Islands as wintering habitat. These observations where made during a research survey by the NOAA Ship Oscar Elton Sette across the western end of the archipelago in March 2007. "It was quite surprising actually," stated Dr. Dave Johnston, the team leader for cetacean research at the Pacific Islands Fisheries Science Center. "Whenever we surveyed in shallow, warm areas, we would find humpback whales." Johnston and his colleagues were especially intrigued when they observed small calves accompanying some of the larger whales and witnessed humpbacks behaving in ways usually associated with breeding - further evidence that humpbacks were wintering in these remote waters.

Prior to this study, it was thought that humpbacks wintering in Hawaii occupied only the main Hawaiian Islands farther south. "This is a significant finding," noted Dave Mattila, the Science Coordinator of the Hawaiian Islands Humpback Whale National Marine Sanctuary. "We've seen humpbacks expand their use of the main Hawaiian Islands, but were unaware that they also used the Northwestern Hawaiian Islands as wintering habitat." In fact, researchers estimate there is about twice as much suitable wintering habitat in waters of the Northwestern Hawaiian Islands than in the main Hawaiian Islands..

The new finding underscores how little is known about the whales and dolphins inhabiting waters of the Northwestern Hawaiian Islands and the need for further research. A follow-up cruise on the Sette is scheduled for February 2008. "I'm excited to get back up there," stated Johnston. "Every time we leave port, we embark on a voyage of discovery."

The open-access Endangered Species Research article is available online at http://www.int-res.com/articles/esr2007/3/n003p249.pdf (pdf)