Aerial surveys of humpback whales

I am just back from the second of three aerial surveys of humpback whales in the four-island regions of Maui, Molokai, Lanai and Kahoolawe we are conducting this spring. Dr. Joe Mobley, Dr. Mark Deakos and The Dolphin Institute are taking on these surveys to understand the present status of humpback whale numbers, production of calves, and habitat distribution in Hawaii. The last surveys took place over 15 years ago.

North Pacific humpback whales in Hawaiian waters have steadily been increasing since the mid- to late-1970s when they were first surveyed by pioneer Dr. Louis M. Herman and his students at University of Hawaii at Manoa.  In his earliest surveys, Dr. Herman estimated less than 1000 whales visiting Hawaii.  By 2006, data from the multi-nation, multi-research group SPLASH project of which TDI was a contributor showed this number had increased more than 10-fold. However, since 2016 there has been a noticeable and concerning apparent reduction in the numbers of humpback whales, including calves, in Hawaiian waters as measured by various research groups using boat-based transect surveys, shore-based systematic scan sampling techniques, and passive acoustic recordings.

On our most recent flight, we had numerous sightings of humpbacks concentrated mainly in the traditional “hot spots” of the Auau Channel and Penguin Bank.  Over the course both aerial surveys this season, we have sighted humpback whales in various groups including mother-calf pairs and competitive groups. We have also seen other cetaceans such as fin whales, pilot whales and spinner dolphins, and even manta rays and a whale shark.

Our objective this season is to complete three surveys. In order to accomplish this goal, we have received about $11,000 from private donations, and TDI will contribute an additional $2,000 to round out the costs of the final flight.

Next year, we have our eye on humpback whale surveys around all the main Hawaiian Islands. This is critical for understanding changes in the number of whales and calves, and their distribution in the main Hawaiian Islands in the face of changes in water temperature and productivity in the North Pacific. In order to conduct this next series of flights, we will need to raise $100,000. We’ve made a great start through a grant for $8,000 from the Maui-based non-profit organization Whale Trust, and now we need your help. Please join this urgent effort to better understand what is happening with Hawaii’s humpback whales and help us raise the remainder of the funds. Your tax-deductible contribution to TDI specifying “2020 aerial survey project” can go a long way to help us reach our goal. Mahalo!

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