Question: I read an article about the whale count last month. How do they know the number is of individual whales and not whales being counted more than once?
Answer: You are referring to the Hawaiian Islands Humpback Whale National Marine Sanctuary’s Ocean Count and the Pacific Whale Foundation’s Great Whale Count, which are conducted on the same days in January, February and March, to collect data on humpback whales around the main Hawaiian islands. Volunteers for Ocean Count observe whales from Oahu, Molokai, Kauai and the Big Island, while volunteers for the Great Whale Count observe whales from Maui and Lanai. The next count is scheduled for March 30, and volunteers can sign up now with either organization. For details, go to https://oceancount.org/ or https://www.pacificwhale.org.
As for how to avoid counting the same whale twice the same day, we turned to Cindy Among-Serrao, Ocean Count coordinator, and Jens Currie, chief scientist for the Pacific Whale Foundation.
“There is no flawless method to ensure that we aren’t double-counting humpback whales during our counts as they are wild animals who have the whole ocean to explore and we are all doing these counts from the shoreline, but we do try to mitigate that as much as possible by having trained site leaders at every count site,” Among-Serrao said in an email.
Each year, site leaders are taught, among other things, how to minimize double-counting. Tactics include scanning the water from left to right across the entire visual plane during each time interval, rather than dividing the site into “pie pieces,” according to an online presentation.
“The site leaders then take the knowledge and skills they learned to guide the volunteers at their site on the event days and provide instructions and a brief training in the morning before the start of the data collection. With that said, even with some mitigation there is still the possibility of whales being double-counted, as some whales may travel around the coastline of an island during the counts and may be sighted at a different site during a different time period,” she said, adding that the group’s public announcements note that a count total might include duplicate sightings.
The counts provide “a snapshot of whale activity and trends in relative abundance of whales from the shoreline,” she said.
Currie emphasized that biases, such as the potential for double-counting, persist consistently across all sites and years. “In instances where we are unable to eliminate these biases entirely, we ensure that they are consistently applied year after year and across all sites. This helps to maintain the consistency of any potential double-counting. While the daily count numbers are intriguing, what truly matters is observing the trends over time. We have observed that these count data align with similar trends identified through more systematic research projects. For instance, between 1995 and 2013, there was a consistent annual increase in count numbers by approximately 5.5% to 6%, which matched the estimated growth rate of the North Pacific humpback whale population during that period,” he said in an email.
The whales migrate from Alaska every year to mate, give birth and nurse their young in Hawaii’s warmer waters.
Town hall tonight
Honolulu Mayor Rick Blangiardi is kicking off a new round of town hall sessions tonight at Kapolei High School, for residents of Kapolei, Ewa and Makakilo. The meeting will be in the school cafeteria, starting at 6:30 p.m., according to a news release from the mayor’s office. This will be the first of 11 town hall meetings set across Oahu, where the mayor and senior administration officials can hear directly from area residents. For the schedule, see www8.honolulu.gov/mayor/townhall/.
Mahalo
Mahalo to a very helpful family in the parking lot of the Pearl City Home Depot on Saturday. The family (husband, wife and child) helped me load my pickup truck with hollow tiles from Home Depot. What would have taken me about 20 minutes was completed in half the time. I did not get their names. Again, thank you very much for your assistance, it was really appreciated. — Grateful kupuna
Write to Kokua Line at Honolulu Star-Advertiser, 500 Ala Moana Blvd., Suite 7-500, Honolulu, HI 96813; call 808-529-4773; or email kokualine@staradvertiser.com.
