NOAA ‘mother ship’ circling Hawaiian Islands as scientist scuba divers monitor coral reefs

Beachgoers and boaters in the Hawaiian Islands may have spied a large white vessel offshore in recent days.

The ship wending its way through the blue waters of the tropical archipelago is Oscar Elton Sette – a 224-foot research vessel operated by the National Oceanic and Atmospheric Administration, now conducting the first Hawai‘i portion of the National Coral Reef Monitoring Program in five years.

“It’s quite intense,” said NOAA marine biologist Jennifer Samson, who leads the monitoring program in the Pacific Islands. “We deploy up to four small boats a day from the large mother ship, and then everyone’s diving.”

The National Coral Reef Monitoring Program encompasses sites throughout the Pacific and Atlantic oceans, the Gulf of Mexico and the Caribbean. In the Pacific, NOAA scientists circulate between the Hawaiian Islands; the Commonwealth of the Northern Mariana Islands; American Sāmoa; and “Pacific Remote Island Areas” located at the center of the watery triangle formed by the three prior locations.

Hawai‘i is usually surveyed every three years, yet the last expedition undertaken to do so occurred in 2019, due to the onset of the COVID-19 pandemic – which canceled monitoring program missions in 2020 and 2021.

Twenty scientists, in addition to crew members, are aboard Oscar Elton Sette, which departed its home port of Honolulu on July 1. The ship surveyed coral reefs in Maui waters before spending much of last week around the Big Island. It is presently near Kahoʻolawe, a 45-square-mile island about seven miles southwest of Maui.

Oscar Elton Sette’s scientists and crew are logging more than 12-hour workdays conducting operations that include multiple dives per day at depths up to nearly 100 feet, or 30 meters. Each dive location is randomly selected within certain parameters and non-extractive – meaning NOAA’s underwater surveyors only observe and record what they see.

“We record all the fish and benthic habitats,” said Samson. “What does the bottom look like? What are the different corals growing on the bottom?”

Photographs taken of the seabed, or benthic habitat, are used to create a “3D mosaic of the reef” from which data can be extracted using artificial intelligence. (AI, according to Samson, is good at identifying common varieties of coral. But human experts are still needed to distinguish rare species.)

The divers are also taking time during their voyage to perform some work related to climate science: Replacing underwater instruments, some of which have recorded their marine surroundings’ temperature every 15 minutes for the past three years.

Yet in addition to surveying habitat, NOAA’s divers are concerned with counting fish. Such a brief description of their work may bring a Seussian rhyme to mind – “One fish, two fish, red fish, blue fish” – but the scientists’ task is an undoubtedly rigorous one. Marine biologist Kaylyn McCoy learned to identify some 300 species before embarking on her first expedition more than a decade ago.

“Once we’re underwater, we have a certain survey area that we’re looking at …. We’re identifying the fish in that survey area, we’re counting how many of each species is there and we’re also estimating the size of the fish,” McCoy, who is not participating in the current expedition, said.

McCoy and her counterparts when counting fish align themselves nearly 50 feet, or 15 meters, apart before transecting their designated survey area, making marks on waxy waterproof paper as they go along.

So much time spent beneath the waves occasionally yields truly awe-inspiring moments. McCoy once happened upon a few massive ulua, or giant trevally, off Nāpali Coast on Kaua‘i. Another underwater encounter – this time near Jarvis Island, a tiny coral atoll 1,305 nautical miles south of Honolulu – was even more remarkable.

“After a dive, I was coming up … I saw a hammerhead shark swimming underneath me,” McCoy recalled. “I was so fascinated by this one shark swimming below me, and then my buddy tapped me on the shoulder and pointed behind me.

“I turned around and there was a school of over 100 hammerhead sharks that was swimming towards us,” McCoy continued. “They did not care about us at all. I don’t even think they noticed us there in the water. They just kept swimming on by, doing their thing, and it was the most magical thing I’ve ever seen – to be surrounded by a school of hammerhead sharks that just couldn’t care less that we were there.”

All data collected by those now aboard Oscar Elton Sette, once analyzed, will be made publicly available – as is all information collected and collated under the National Coral Reef Monitoring Program. The reports are used by federal lawmakers, state agencies, NOAA leadership and the interested public.

The state of Hawai‘i Department of Land and Natural Resources Division of Aquatic Resources is one of several entities that will pay attention to findings made by those now aboard Oscar Elton Sette.

“One of the main reasons that DAR is really interested in our data is they actually have the management responsibility for coral reefs and coral reef fish [barring certain federally-managed species],” Samson explained. “The data we provide definitely is used by DAR to assess how well are the different fish doing, that are part of their target species list.”

The scientists’ records of coral reef conditions are also utilized in other scenarios, such as in cases of proposed infrastructure.

“Maybe the Navy wants to build a pier and we say that’s an area that’s got highly diverse corals and very high fish density,” Samson said. “The project may get moved or changed to not have such an impact.”

The coral reefs of the Hawaiian Islands average “fair” condition, according to the latest National Coral Reef Monitoring Program status report for the region. The rating falls squarely in the middle of a rating system ranging from “very good” to “critical.”

Kaua‘i and Ni‘ihau, the westernmost of the main Hawaiian Islands, obtained the highest fish score in the 2018 report. On the far side of the island chain, the Big Island boasted the highest “human connections” score – meaning many locals are supportive of, and take part in, coral reef management and protection.

Indeed, construction of a coral nursery was underway last year in Kona, just one part of a $25 million program to preserve and restore the coral reefs of the Big Island’s western shores.

Coral reefs – and attempts to save them in a world threatened by climate change – frequently make headlines in the Aloha State. In February, The Nature Conservancy unveiled an expanded coral reef policy for the Hawaiian Islands, more than doubling the area covered under its previous policy, which was the first of its kind in United States history.

More recently, Division of Aquatic Resources personnel on Kaua‘i disclosed a person or persons unknown had planted non-native coral at ‘Anini Beach – the longest reef in the state. They have since removed the offending coral, which could potentially introduce disease or wreak ecological havoc through other means, on multiple occasions.

“Fair is what we expect for the populated areas that we survey. Usually, it’s the really remote areas that we see with healthier levels of fish biomass and higher coral cover,” McCoy said of coral reefs in Hawai‘i. “It’s on par with other populated areas that we surveyed.”

From Kahoʻolawe, Oscar Elton Sette will proceed to Moloka‘i, make a one-day return to Maui on July 19, then continue to waters off Lāna‘i and O‘ahu. It will conclude its nearly month-long voyage by circling Kaua‘i and Ni‘ihau from July 24 through 29.

The mission, however, will not end there. Many members of the ship’s science party will disembark Oscar Elton Sette during a brief stopover in Honolulu. Then the ship – manned by a fresh batch of scientists – will continue to the Northwestern Hawaiian Islands within the Papahānaumokuākea Marine National Monument.

Do you want to follow along with the scientists and crew of Oscar Elton Sette as they monitor the coral reefs of Hawai‘i? NOAA personnel are updating an online photo gallery of the expedition here.

To explore the National Coral Reef Monitoring Program data visualization tool – a comprehensive collection of coral, fish, climate and socioeconomic data from all US coral reef jurisdictions – click here.