For people who love whales, a high point of this winter’s breeding and birthing season for migratory North Pacific humpback whales in Hawaii was a surge of 134% in whale sightings by volunteers in January’s one-day Great Whale Count on Maui, compared with January 2019.
But the February count, on a windy day with poor visibility, saw a 22.4% decrease from the previous year, and then March didn’t happen at all because of the COVID-19 lockdown, said Stephanie Stack, chief biologist at the Maui-based Pacific Whale Foundation.
From the viewpoint of the whales themselves, the highlight of the season, which lasts from November to May and is now winding to a close, might have been the near-disappearance of humans from cetaceans’ habitat since March 20, when the state Department of Natural Resources’ Division of Boating and Ocean Recreation suspended all commercial operator permits in state ocean waters, including whale-watching tours.
Hotel occupancy on Maui, the most popular island for whale watching, declined 40% from March 2019.
Although scientists, under stay-at-home orders like the rest of us, couldn’t get out in the field to directly observe the impact of this radically quieter environment on the marine mammals, it could only have helped humpback whales during this sensitive, vulnerable time in their life cycle, several Hawaii scientists told the Honolulu Star-Advertiser.
“The clearest benefit of the reduction in vessel traffic is to humpback mothers and nursing calves, who tend to be somewhat reclusive,” said Marc Lammers, research coordinator for the Hawaiian Islands Humpback Whale National Marine Sanctuary, which conducts the Sanctuary Ocean Count of whales sighted off Oahu, Kauai and Hawaii island on the same days as the Maui count.
“Not having humans either trying to view them or, in some cases, interact with them will be a huge benefit for the mother, whose priority is to protect and nurse her calf so it can be strong enough to make the trip to Alaska,” he said. “It allows her to conserve her energy and transfer that energy to her calf in peace, without having to respond to stand-up paddlers and five or six boats approaching at a time.”
On April 2, fishermen alerted staff at the Humpback Whale Sanctuary to the rare sight of a mother and calf lingering near shore by a sheltered anchorage in Lahaina Small Boat Harbor.
“They thought maybe the calf had got entangled, so we sent someone,” said Blake Moore, director of commercial operations for PacWhale Eco-Adventures, affiliated with Pacific Whale Foundation. “But the whales were just hanging out because they weren’t disturbed by boats going in and out of the harbor.”
He estimated that in Maui County alone, about 200,000 to 250,000 people take whale-watching tours every season, going out on approximately 30 to 40 vessels of varying size.
Nursing in peace
Luckily, while whale field research is now in limbo, the first phase of a promising new study of mothers and nursing calves, employing a breakthrough technology, was completed in Maui waters during 10 days in February, said lead researcher Lars Bejder, director of the University of Hawaii at Manoa’s Marine Mammal Research Program.
To observe and document their nursing behavior, seven newborn humpback whale calves were fitted with yellow suction-cup tags containing cameras, acoustic recorders, depth sensors and accelerometers in the project. Photos were also taken by overhead drones.
Stunning photos and videos taken in clear, blue waters document the nursing pairs’ behavior and interactions close up.
“The videos allowed us to quantify, for the first time, the nursing bouts which are so critical for these animals,” Bejder said.
He noted the whales do not feed during breeding season, but live off the fat they store during their summer feeding season in Alaska.
“What we are trying to understand with these new technologies is how much time the calves need to nurse from their moms to be able to get strong and big enough to make the journey back up north,” he said.
The floatable tags, he added, were attached with suction cups that were programmed to detach in four to 22 hours, after which a small armada of boats from the scientific and whale-watching communities searched far and wide and retrieved every one, Bejder said, expressing thanks for project assistance from the Humpback Whale Sanctuary, Pacific Whale Foundation, Oceanwide Science Institute, Molokai Ocean Tours, PacWhale Eco-Adventures and Rachel and John Sprague.
Because the hydrophones on the tags could record boat engines, the sounds of which did not crop up, “it looks like most of the nursing took place without any human activity around them,” Bejder said. “These tags are allowing us a base line of what is natural behavior, and over the next couple of years, we can see if the nursing bouts change when boats are around.”
In addition, the accelerometer data let scientists measure the fine-scale behavior, movement and breathing patterns of the tagged whales, and the calves’ length, body condition and overall health could be calculated from the pictures taken by drones.
“This is part of a larger program trying to evaluate the effects of climate change and human activity on these animals,” Bejder said.
While Stack at the Pacific Whale Foundation agreed with Bejder and Lammers that a drop-off in human activity would benefit the whales, “the whales aren’t getting as much of a break as maybe we thought they were,” she said.
“Surprisingly, there’s still a fair bit of boat traffic out there. Shipping has been unaffected, and we’ve seen a lot of private boat owners doing whale watching.”
Dolphins and turtles too
Citizen volunteers have been providing some wildlife conservation groups with anecdotal glimpses of other native marine animals catching a breather from tourists’ hot pursuit.
“We haven’t been able to go out and observe, but since the shutdown we have heard from people, and people have sent us videos taken from shore, of Hawaiian spinner dolphins resting, coming in closer to shore at Kealakekua Bay” now that its waters are empty of humans, said Stacia Marcoux, an aquatic biologist with DLNR’s Division of Aquatic Resources who lives in Kailua-Kona.
The dolphins’ natural behavior is to rest all day in sheltered, shallow bays and feed in the open sea at night, Marcoux said, but their rest has been disrupted for decades by tours or individuals who come by boat, stand-up paddleboard and kayak to swim and try to interact with the wild creatures.
In a study conducted by Julian Tyne of Murdoch University in Perth, Australia from 2010 to 2014, Hawaiian spinner dolphins in Kealakekua Bay were exposed to humans coming within 100 meters during daytime hours, with only 10 minutes between exposures.
“They spend over 90% of their rest time in these sheltered bays, but people were there for over 80% of their day, so it would potentially change (the animals’) behaviors,” Marcoux said.
Now, on the southern side of Kealakekua Bay near Napopo, the dolphins are venturing into shallow waters formerly filled with swimmers and kayakers, and they’re “swimming tighter together in a group, spending shorter amounts of time at the surface, not slapping tails or jumping or spinning,” she said. “It’s all indicative of resting behavior.”
Since human activity surged in the 1980s, Marcoux added, researchers had found the dolphins were using Kealakekua and other bays less frequently and staying for shorter amounts of time, “potentially not resting as much as in the past.”
On Maui, in a similar vein, residents have been reporting changes in the activity of green sea turtles, a threatened species in Hawaii, since the COVID-19 lockdown and a 14-day quarantine imposed on arrivals, said Hannah Bernard, executive director of the Hawaii Wildlife Fund.
In addition to Hookipa Beach on Maui’s north shore, where the nonprofit has educated the public to leave 100 yards between people and turtles basking on the shore, “there are now additional beaches, I’m hearing, that are being used by basking turtles that they weren’t using when there were so many people there.”
Basking, Bernard added, is a rare daytime behavior that only green turtles exhibit. The season for nesting, which typically happens at night, begins in May.
Sounds of silence
It’s not only commerce that’s being stymied by the new coronavirus; scientists are eager to get back to work and learn firsthand about the effects of human absence from Hawaii’s ocean habitat.
“What we’re observing now is unprecedented to anything any of us have experienced here in Hawaii in modern times, so this is a unique natural experiment,” Lammers said, adding he doesn’t know when his team will be able to retrieve their extensive network of underwater hydrophones that record the male humpback whales’ songs each breeding season.
They normally collect the data by mid-May, but whenever they are able to access it, “I think it will not only reveal quite a bit what the ocean really sounds like with no human activity,” he said, “but more broadly what animals do when you remove the vast majority of the human element.”
It will be interesting, Lammers said, to see whether the whales may have lingered longer in Hawaii waters than usual, or whether more singing activity than usual took place.