If the sunscreen-slicked bodies swarming Hawaii’s most popular beaches vanished, would near-shore fish stocks swell?

On Kauai, where a disastrous springtime flood quashed the average daily visitor count at Haena’s celebrated end-of-the-road lagoon from a couple thousand to virtually none, residents report a summer season characterized by something not seen here since the 1950s: tourist-free waters teeming with fish.

Not only do species like kala, or bluespine unicornfish, seem more plentiful than normal, but they are swimming in waters so shallow that their tails breach the surface.

Courtesy of Presley Wann

These observations come from the area’s longtime fishermen, who practice traditional sustainable fishing techniques to protect the ocean resources that feed these rural neighborhoods.

“I’ve got a pretty good fish eye and holy mackerel, they’re all coming back,” said Presley Wann, president of the nonprofit Hui Makaʻāinana o Makana, which aims to restore Native Hawaiian values and stewardship practices. “You can stand on the beach and see them on the reef.”

It’s like they came out of hiding, he said.

But are there really more fish in the shallows? And if there are, could their spike in numbers be the result of a dramatic drop in number of beachgoers?

A Rare Opportunity For Scientists

Over five days in June, a pair of marine scientists wearing masks and snorkels tried to find out.

“The hypothesis is that the fish are coming in because there’s less people, and maybe also because there’s less sunscreen in the water,” said Kosta Stamoulis, an Oahu-based marine ecologist who volunteered his time to count fish in the area. “I totally trust the community’s observations, but it’s another thing if we can capture that in the data and show it scientifically.”

In recent years, Haena waters have been less abundant due to overfishing. So fishermen teamed with the Hawaii Department of Land and Natural Resources to draw up new rules designating Haena as Hawaii’s first Community-Based Subsistence Fishing Area.

Signed into law by Gov. David Ige in August 2015, the legislation sets bag limits for urchins, octopus, and lobster, limits fishing poles to two and forbids commercial fishing and the use of spear guns, among other rules.

Careful management of these natural resources builds community resilience and social networks, supporting the culture of sharing food across neighborhoods in times of abundance.

Larry Loos/Flickr

Haena fishermen say the marine life within the bounds of the CBSFA is already rebounding.

But it’s been impossible to measure the perceived impact of human activity from a preponderance of tourists.

Haena’s beaches, especially Ke’e Beach and the reef known as Tunnels off of Makua Bay, are year-round playgrounds for people who like to swim, snorkel, dive and surf.

Most of that activity came to a halt nearly four months ago when a mid-April deluge damaged hundreds of homes and paused tourism on the farthest reaches of Kauai’s North Shore. The hardest-hit communities of Haena and Wainiha continue to bar entry to tourists, as well as island residents who don’t live in these neighborhoods.

The locals here — trapped but for a 5 mph escorted convoy along the area’s single, storm-ravaged access route — are wistfully returning to treasured cultural sites that for decades have been clogged with tourists. Kids play and ride bikes in the middle of roads previously jammed with traffic.

It seems even the fish are taking notice.

“One day two papios were chasing a school of stick fish and they all started scattering and this was right on the edge of the lagoon at Ke’e,” Wann said. “You didn’t used to see that.”

“I’ve got a pretty good fish eye and holy mackerel, they’re all coming back.” —Presley Wann, president of the nonprofit Hui Makaʻāinana o Makana,

In their survey, Stamoulis and Jade Delevoux, a geospatial analyst at the University of Hawaii Manoa, used scientific methods to count fish and measure the minimum approach distance, or the wariness, of fish. The latter calculation determines how close a swimmer can get to a fish before it wriggles away in fright.

The scientists analyzed the ratio of coral, algae and sand on the seafloor. They also collected sediment and chlorophyll samples.

Analyzing The Toll On Reefs

One outcome of the flood, in addition to temporarily sealing off Haena from tourists and most of Kauai’s residents, is the massive gush of fresh water and sediment that swept down from the mountains, washed through people’s homes and deposited into the sea.

The fresh water likely added nutrients into the ocean that can enhance the growth of plankton, Stamoulis said. If there’s more plankton in these waters, it may attract more of the fish that feed on it.

Sediment, on the other hand, smothers algae and coral — the food and homes of fish.

“It could be that with more fresh water, there’s more nutrients coming in and you start to see certain species of fish attracted to the area because there’s more phytoplankton,” Stamoulis said. “But if the fish are less able to get to their food because of the sediments, it could detract fish.”

Anthony Quintano/Civil Beat

In a related effort to understand the flood’s toll on the reef, scientists at Kauai’s Division of Aquatic Resources, a subset of the state Department of Land and Natural Resources, are working to map major flood debris. Using dive gear, community tips and satellite imagery, DAR scientists are searching depths up to 30 feet for wreckage including cars, roofing material and washing machines.

For their fish study, Stamoulis and Delevaux focused their dives at Ke’e Beach and Makua Bay, two of the region’s most popular attractions.

Their findings are forthcoming, although, anecdotally, Stamoulis said the fish really do seem more plentiful in the shallows. The scientists plan to survey these same waters again when the access road, damaged by landslides and sinkholes, reopens to the public. Then they’ll compare the results of the first survey, conducted in undisturbed waters, with the survey measuring fish numbers and behavior after the throngs of beachgoers have returned.

“To me, having the opportunity to survey this place with tourism set to zero was a unique opportunity to characterize the marine ecosystem,” Delevaux said.

If the research shows a relationship between human activity and fish numbers, it could provide evidence to support new limitations on the number of people permitted to visit certain coastal resources. It could inform a planned update to the rules implemented as part of the area’s CBSFA designation.

State regulators are considering a 900-person daily visitor cap at Haena State Park to address overcrowding issues. Home of Ke’e Beach, ancient sea caves and the famous trailhead to Kalalau, the state park is one of Hawaii’s busiest. Until the flood disrupted tourism, the park attracted up to 2,000 daily visitors.

“The Hawaiians down there, they could care less if the road ever opens,” Wann said. “They’re just so happy to have the peace and tranquility and harmony and the fish come back to the place.”

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