Killer whales intrigue scientists
By Jan TenBruggencate
Advertiser Kaua'i Bureau
Multiple sightings of killer whales in Hawai'i waters in recent years have added to the mystery surrounding one of the least understood marine mammals.
Jan Tenbruggencate • The Honolulu Advertiser
"We know nothing, absolutely nothing, about them," said Daniela Maldini, a zoologist seeking her doctorate from the University of Hawai'i while working with the nonprofit Alaska SeaLife Center.
Daniela Maldini and Peter Nilsson are seeking photographs of Hawai'i killer whales so they can compare them to whales elsewhere.
Marine scientists don't know how many there are around the Islands, where they're from, when they spend time here, or even what kind they are.
"Killer whales are not just one thing. They have their own cultures. They are very culturally different in how they behave and what they feed on," she said.
Peter Nilsson, a marine biologist and graduate student at the University of Alaska at Fairbanks, said there are three known "cultures" of killer whales.
"Residents," which tend to eat fish exclusively, remain in coastal areas, where they stick tightly to their family groups. There are about 300 known individuals in three communities from the Pacific Northwest to the Gulf of Alaska.
"Transients" are meat eaters, feeding on seals and other cetaceans. They range far more widely and can act alone, although they tend to travel in pods.
"Offshore" killer whales are generally considered meat eaters, but also may eat fish, and seldom come near shore. Very little is known about them, although they have been reported to sometimes congregate at sea in groups of 100 or more.
Individuals from the three cultures are not known to interact, and form genetically distinct populations with distinctly different behaviors, Nilsson and Maldini said.
There were reports of pods off Maui in 1997, Kona in 1998, between Kaua'i and Ni'ihau last March and off Lana'i in September. The Lana'i pod was described as eating squid and fish intestines, while the Kaua'i-Ni'ihau pod was feeding on another small cetacean, perhaps a baby humpback whale.
Jean Souza of the Hawaiian Islands Humpback Whale National Marine Sanctuary office on Kaua'i said helicopter pilots and tour boat operators report other sightings around Kaua'i in October.
"I think they are underreported," Maldini said. If they are transient meat eaters, they can tend to be low-profile.
"Transients are sneaky, and you wouldn't know if there are a lot of them."
The researchers are interested in photographs of killer whales around Hawai'i to see whether they can be identified as ones that also populate the Mainland and Alaska coast.
Researchers keep photographic records of most of the whales that appear along the Mainland coast, and could compare Hawai'i whale images with those.
Key identifying characteristics are the dorsal fin and the saddle-shaped white patch behind a killer whale's dorsal fin.
"It's pretty normal for a killer whale to have a range of several hundred to thousands of miles," and the Hawai'i animals could easily be migrants from Alaskan, Canadian or Washington-area waters, she said.
While in the Islands, they could feed on fish, or if meat eaters, on the spinner dolphins that remain in the Islands year-round, as well as seals and other marine mammals.
There are 19 known species of toothed cetaceans around the Islands, Maldini said, including ones commonly known as both whales and dolphins.
She can be reached at daniela_maldini@alaskasealife.org.
Reach Jan TenBruggencate at jant@honoluluadvertiser.com or (808) 245-3074.
