Research continues on Hawaii’s lesser-known cetaceans
In Hawaii’s crystalline waters, some cetaceans get all the attention — usually the charismatic humpback whales and spinner dolphins known for their stunning displays of acrobatics.
However, there are scores of lesser-known species that reside here year-round and deserve recognition, too. In fact, residents and visitors with photos of these animals could help with current research and conservation work.
Since 2000, the Cascadia Research Collective has conducted extensive studies, covering more than 46,000 miles of survey track lines around the main Hawaiian Islands, and have documented more than 1,700 sightings of 18 different species of toothed whales and dolphins. Its work has covered waters up to roughly 5,000 meters deep, but about half of the effort has been in waters 1,000 meters deep or less, said Robin Baird, a research biologist for Cascadia Research Collective.
This 501(c)3 nonprofit, based in Olympia, Wash., has been diligently studying the abundance, movements, diving behavior, genetic relations and social organization of the individuals. The species most interested in are false killer whales, pygmy killer whales, melon-headed whales, and beaked whales.
“One of the main ways we’ve learned about the presence of so many resident populations of toothed whales and dolphins is using individual photo identification, both from our own work and photos contributed by others who work or play on the water,” he said. “With the deep water so close to shore off Kona, there are a lot of normally open-ocean deep water species that we are able work with and get close to. Several have turned out to have resident populations here.”
During a recent ReefTalk at Kaloko-Honokohau National Historical Park, Baird gave an update on several studies Cascadia Research Collective is conducting or assisting with. Baird also spoke about the importance of the public’s involvement in contributing to the nonprofit photo identification catalogs, saying, “Every photo submitted makes a difference and is a valuable resource that helps fill in the gaps when we’re not here to observe and interpret.” To submit a photo, email email@example.com or call (360) 943-7325.
Baird explained the photo catalogs have helped a great deal in estimating the population size of six species so far, including the Cuvier’s beaked whale, whose population off the island’s west side is about 50 individuals. He also pointed out that more is known about Hawaii’s pygmy killer whales, one of the least-frequently encountered species of oceanic dolphins, thanks to the long-term photo identification effort by local researcher Dan McSweeney of the Wild Whale Research Foundation and regular photo contributions by other residents.
Baird said his team has seen pygmy sperm whales only a handful of times while the dwarf sperm whale, which is from the same family, has been spotted more than 70 times. He added, “Both have a reputation of being difficult to keep track of and approach because of their long dive times, logging, unpredictable travel patterns and gift for avoiding boats.”
One of his favorite species is the false killer whale, the least abundant of the 18 species of toothed whales and dolphins found in Hawaiian waters. There is a small population associated with the main Hawaiian Islands, about 150 to 160 individuals, as well as a pelagic population, around 480, and a Northwestern Hawaiian Islands population. There are at least five different social groups, proved by mapping the network of interactions of the individuals. The social networks help researchers assess populations, Baird said.
Not only are false killer whales swift and agile top predators that eat big things, such as squid and fish, their feeding habits can often be easily observed because their dinning is very social and can happen at the ocean’s surface, Baird said. To give a better idea of the false killer whales’ unique way of hunting and eating their prey cooperatively, he told a story.
“Once they’ve caught a fish, each false killer whale takes a bite, then passes it back and forth to each other. If there are people nearby, false killer whales have been known to offer some to them, too,” Baird told the packed ReefTalk audience. “While photographing a group underwater, Dan McSweeney once had a false killer whale ‘hand’ a large ahi to him. It spit it out right in front of him. Of course, he handed it right back, which I think we would all agree was the right thing to do.”
Due to their vulnerability, false killer whales were listed as endangered last year. Among the threats to their survival include the ingestion of hooked fish taken of lines and fish hooks from free-swimming hooked fish. False killer whales have been observed taking taking the bait off longline fishing hooks and risk becoming hooked or entangled in the lines, a situation that can become deadly. Effective as of February, the National Marine Fisheries Service is requiring weak circle hooks for the Hawaii-based longline fishery, designed to retain the target catch, but release larger accidental bycatch like false killer whales and minimize the risk of mortality, Baird said.
Cascadia Research Collective is on Hawaii Island to conduct a field expedition, ending May 28, and is using a 27-foot Boston Whaler for surveying. The goal is learn more about the sounds melon-headed whales and false killer whales make. Besides collecting data on the sounds through suction-cup attached digital tags and an acoustic recorder, the researchers will also be recording how the species behave and their use of the environment when making sounds, Baird said.
As of Thursday, the researchers had spotted and identified two groups of melon-headed whales, which are part of the Kohala resident population, but were not able to get close enough to deploy tags, Baird said.
Still, the nonprofit isn’t waiting idle. Like every trip, the team obtains photos from most of the odontocetes, as well as unusual seabirds, encountered to contribute to ongoing studies. When possible, researchers collect biopsy samples for toxicology and genetic studies or attempt to deploy tags for the studying of movements and diving behavior, Baird said. Also collected are the floating carcasses of squid and octopus, which provides a greater understanding of what species exist in the area, he added.
To learn more about the nonprofit and its work, visit www.cascadiaresearch.org.