Great Whale Count

Project Name:

The Great Whale Count

Project Site(s):

Twelve coastal sites along the southern and western shores of the island of Maui, in an area extending from Makena to Kapalua. The last site is located at Hookipa Beach Park on Maui’s north shore. All sites, except Hookipa, are situated within the Hawaiian Islands Humpback Whale National Marine Sanctuary.

Project Aims:

Using citizen science to engage members of the public and promote environmental stewardship, while contributing toward a long-term humpback whale sighting dataset.

Project Methodology:

This study consists of one day of point-counts each year conducted simultaneously from multiple coastal sites along the southern shores of the island of Maui. The count takes place annually on the last Saturday in February, which generally coincides with the peak of the breeding and calving season. Sites are monitored by teams of observers consisting of a site leader and a group of volunteers.

Teams perform scans within concurrent 20-minute intervals between 0830 and 1200. During the first 10 minutes, observers report all sightings of humpback whales within the survey area (three nautical mile radius from each site). During each scan, number of pods, individuals in each group, presence of calves, distance and compass bearing to each pod are noted. Environmental conditions are also recorded including sea state, glare percentage, as well as wind speed and direction. Immediately following this scan, observers devote five minutes to recording conspicuous behaviors (e.g. breaches, pectoral fin slaps, tail slaps, and peduncle throws). Observers rest for the remaining five minutes before the next 10-minute scan.

Please note that the Great Whale Count does not aim at calculating a population estimate but rather a proportion of humpback whales within three miles from shore. In addition, sites are situated three miles apart to ensure that there is no overlap between them.

Management Outcomes:

Citizen science is becoming a widespread tool for ecological and environmental monitoring, especially in an era of fiscal restraint by governments and NGOs. Not only can citizen science engage members of the public and promote environmental stewardship, but the data can be useful in ecosystem monitoring and assessment. The Great Whale Count data indicate an overall upward trend in the number of whales sighted, with a 6.3% increase of humpback whale sightings per year in the Maui coastal waters over the past ten years. Our recent publication (Tonachella et al., 2012) indicates that the Great Whale Count results correlates to research showing a humpback whale population increase in the North Pacific at a rate of 7-8% each year, with a current population estimated at approximately 22,000 individuals.

This systematic counting method allows us to monitor changes in humpback whale sightings from year to year and provides a valuable long-term snapshot view at Hawaii’s humpback whale population. Overall, we are seeing evidence of a growing number of whale sightings, even though the proportion of whales sighted fluctuates each year.


Tonachella et al. (2012). Predicting trends in humpback whale abundance using citizen science. Pacific Conservation Biology, 18: 297-309.


GWC final count over the past years:

Press articles:


Additional Files: