On a recent outing off the Kona Coast, Michael Nakachi and his son, Kaikea, stopped their boat in the morning light just outside Honokohau Harbor and tossed hookupu — offerings — of ti leaves into the ocean before motoring any farther.

The elder Nakachi also placed mango wrapped in ti leaf over the side. The fruit came from a tree at his father’s house. Ling, the family patriarch, had just died in May.

The offerings scattered across the water. Then, moments later, several sandbar sharks emerged and swirled around the leaves, attracted by the organic matter. After a minute or so they disappeared below the surface.

The brief encounter was no accident. The Nakachis know these waters intimately, and they know precisely where to find the animals. They’re the descendants of Hawaiian kahu mano, or “shark keepers,” and in recent years they’ve doggedly sought to reconnect with their family legacy.

In fact, the Nakachis have been quietly pioneering a modern version of their ancestors’ cultural practice, one that involves exhaustive shark research on the water. They’ve done this, they say, with the blessing of prominent families rooted on the island.

“We try as much as possible to jump in the water, actively engage animals whether it be scuba, free diving, rebreather … all these various technologies,” said Michael Nakachi, who’s 55 and was raised in Waimanalo. His Hawaiian ancestry traces back to Maui. “And for most kanaka (Native Hawaiians) I think you have to embrace that. How can we use certain things that will … authenticate what the ancestors already knew?”

Unlike Western approaches, however, their research methods are strictly — adamantly — non-invasive. There’s no hooking, catching or handling of the sharks in ways that stress them or, in some cases, kill them.

Instead, Kaikea, who’s 27 and pursuing a master’s degree in tropical conservation biology and environmental science at the University of Hawaii Hilo, painstakingly documents the sharks and other marine life in West Hawaii waters with the thousands of photos and videos he’s taken. He’ll use them for the thesis he hopes to complete by year’s end. It relies on this “encounter history” to track individual sharks by their markings, both their presence and absence.

His image database, which he said is nearly two terabytes (2,000 gigabytes) worth of data, also includes their mating history and their “fishery interactions.” In other words, it records when individuals are pierced and tangled with damaging hooks, lines and other fishing equipment. Using a computer program, he extrapolates local shark species populations based on the individuals he records.

It’s observation-based — “doing things more on the sharks’ terms than the researcher’s terms,” Kaikea said, and it’s similar to the role kahu mano played in Hawaiian society prior to Western contact.

“People say, ‘science versus culture,’ but in many times the culture was science,” Kaikea said during an outing off Kona in August. “A kahu mano is taking care of a shark. He knows that shark personally. How else would you individually identify it, or name it, or understand its genealogy? It’s time, observation and understanding.”

Getting local academia to see his perspective has been difficult, though. The more culturally sensitive approach that the Nakachis advocate directly challenges how shark research is done at UH, and the degree to which invasiveness and shark mortality are acceptable.

When he started his master’s Kaikea clashed with his adviser, he said. It took him a few years to find the right adviser and faculty committee to support his thesis.

The Nakachis have also butted heads with established UH researchers over legislation that seeks to create stronger shark protections in state waters. They say such added protections are needed after viewing numerous troubling human-shark interactions during their regular outings, and noticing a decline of apex predators in the waters they chronicle.

But the researchers, including Kim Holland, who founded UH’s Shark Research Group at the Hawaii Institute of Marine Biology, say the legislation would add onerous bureaucracy to their efforts, hampering further study and hurting shark conservation in the long run.

The elder Nakachi said those researchers simply don’t grasp that in “old-school” Hawaiian values, asking for permission before entering a place is key.

“They’ve done a lot of great things,” Michael acknowledged, but “there is zero dialogue. There’s no asking permission. There’s no feel for the animal. It’s all about data.”

Traditional Knowledge, Observational Research

While Kaikea has delved into research, his father largely emulates his kahu mano lineage as a staunch marine conservationist.

He’s been active in the contentious local battles over aquarium fishing, and joined the legal action that resulted in a Supreme Court ruling against the practice in West Hawaii.

This spring, he joined another lawsuit in his role as cultural practitioner. It recently led to stronger federal protections for the oceanic whitetip shark, a species whose numbers have been decimated in recent decades in large part due to commercial fishing.

Those familiar with the oceanic whitetip describe it as a “cruiser” — a pelagic shark that covers vast ocean distances, conserving energy with its large pectoral fin and swooping in fast on fish prey near the sea surface.

The evolutionary traits that made the once-abundant species such an impressive predator are the same ones leading it toward extinction. Oceanic whitetips are now killed en masse as industrial fishing bycatch, hooked and tangled on longlines and purse seine nets.

More than 300,000 oceanic whitetip sharks have died as bycatch in commercial fishing nets off Hawaii and American Samoa since 2013, and the species is believed to have declined by as much as 95% since the mid-1990s, according to a release from the nonprofit law organization Earthjustice.

Nakachi’s recent suit, filed with Earthjustice and the Conservation Council for Hawaii, prompted federal officials to finally recognize the oceanic whitetip as overfished. Now, the Western Pacific Regional Fishery Management Council, or Wespac, has a year to develop a plan to help protect the shark population.

Wespac discussed its need for mitigation measures during its general meeting this past week, including changes to the gear and better handling practices.

“We think that they are comparatively surface-oriented. They’re not the deep divers going after squid,” said Holland, of UH’s Shark Research Group, of the oceanic whitetip. “We really don’t know much about their range of movement.”

Generally, to better manage and protect shark populations you need to track them, Holland said. And to track them, you need to tag them.

That means using the intrusive methods the Nakachis reject, including hooking and catching the animals, turning them on their bellies, which puts them in a catatonic-like state, and, in some cases, cutting an incision to implant the tag.

Holland said that of the several hundred sharks his group has tagged in recent decades, only a “handful” have died during the process. He described a death as an “extremely rare and unusual event.”

“We have great respect for the animals … and that’s what seems to get lost,” Holland said.

The tracking methods have helped save thousands of sharks, Holland said. When they proved that tiger sharks’ movements are wide-ranging, it prompted the state to enact policies against shark hunts following an attack on a person.

“There is room at the table for traditional knowledge, the observational research that the Nakachis are promoting, and modern science,” Holland said. But you can’t get the tracking data “by just looking at them.”

Kaikea counters that Western scientists could develop less-invasive, more culturally sensitive ways to tag the sharks and reduce mortality.

The catch, he said, is that those methods would likely be more difficult, time-consuming and expensive. For example, researchers could pole-spear or spear-gun the tags into the sharks without hooking them. There would likely be botched attempts and expensive tags lost, but it would be better for the well-being of the sharks, he said.

His observations while swimming in open water with species such as tigers carry more risk, but Kaikea says his knowledge and experience with the animals help offset that.

“The possibilities are nearly endless when you’re developing something,” Kaikea said. “There are all sorts of ideas and options, but rather than sticking to the status quo of what’s easy and cost-effective, people need to start getting creative and putting the sharks first in their research.”

‘A Wasteful Practice’

Kaikea said he encountered similar attitudes studying oceanography as an undergraduate in Florida, where sharks found dead in researchers’ gill nets simply meant another specimen for them to study.

When he graduated and returned home to Hawaiian waters, “the biggest change wasn’t necessarily in the resource itself but … a shift in the people using the ocean and how they’re using it.”

The Nakachis say they’re concerned about the growing number of commercial shark encounters happening offshore, where operators use palu — bait — to repeatedly lure the animals to the surface and alter their behavior so that visitors might take photos to post on social media.

The pair also worry about other encounters that harm the animals, and the limited number of state Department of Land and Natural Resources enforcement officers available to monitor the entire West Hawaii coast.

During their trip in August, the Nakachis motored to a spot known to be popular with gray reef sharks. An opelu (mackerel) fisherman relatively new to those waters was already there.

The longtime opelu fishermen typically fish elsewhere so they don’t have to protect the catch in their nets from the sharks, they said. As the Nakachis approached, the fisherman abruptly motored off.

When Kaikea dived in the water there were no sharks swimming in that usual spot, likely because the current was too strong.

Kaikea did, however, find a juvenile gray reef shark twitching and dying on the sea floor. Whatever happened to it had occurred recently, he said.

They suspect it had some type of encounter with the fisherman, one that left it severely stressed and unable to recover. Its white underside swayed and stood out against the sea floor’s dark rock. Kaikea couldn’t reach it with the strong current to investigate further.

The discovery bothered the Nakachis the rest of the day. Michael regretted not bringing tanks and scuba gear, which might have helped them determine what happened.

“It’s just sad that you give back to Kanaloa that way,” Nakachi said, referring to the traditional Hawaiian god of the ocean. “A wasteful practice.”

Discovering A Legacy

The Nakachis try to make these trips up and down the shore to survey several times a week. They’re able to go so frequently, Michael Nakachi said, thanks to Moana Ohana, a private recreational boating club that he helps run.

Its members help financially support the cultural practice, and the business model gives them the flexibility they need to do the work, he said.

Nakachi said he and his family weren’t aware of their kahu mano lineage until his grandmother’s cousin, Pilahi Paki, the Hawaiian elder who’s known for writing Hawaii’s Aloha Spirit law, revealed it to them during an important family reunion in Aiea in the early 1970s.

The gathering took place after Nakachi’s father, Ling, was nearly lost at sea. He and another family member had been rescued about 30 hours after their fishing boat capsized in the rough waters of the Kaiwi channel off Oahu, according to Nakachi. Another family member died in the water.

According to Nakachi, Paki asked Ling if he had seen any sharks shadowing them in the water, and he responded that while adrift he was aware of a “calming presence” and did see the large shape of shark swimming near them.

“She broke into tears,” Nakachi said of Paki at the gathering. “‘I’m sorry that I was never there and didn’t explain much to you about who we are and where we come from as a family.’”

She then shared their deeper family connection to the animals, and a lineage of kahu mano that traces back to Maui. Much of that legacy was lost with Michael’s grandmother, who died when Ling was a small boy, he said.

Now, the Nakachis strive to define what it means to be kahu mano in the modern era. Michael’s daugher, Alohi, is also pursuing a PhD degree that focuses on coastal marine management.

“For me, I take every chance I get to immerse myself in the place and try to regain some of that knowledge,” Kaikea said.

“Now we’re trying to form our own moolelo (history) along our own understanding of place, and you can only get that by putting in the time.”