Coral Reef Monitoring in the Pacific

Every year, a research team conducts monitoring surveys to assess coral reef health across the Pacific.

Pacific Islands

A school of black jack fish swims above a field of colorful corals.

A school of black jacks swims through a field of branching Acropora corals at Baker Island, where scientists were recording data. Credit: NOAA Fisheries/Jeffrey Milisen

Coral reef ecosystems are full of plants and animals that provide crucial coastal protection, food, and livelihoods to millions of people around the world. Threats to coral reefs and marine ecosystems such as climate change, ocean acidification, disease, and land-based sources of pollution are growing.

NOAA’s Coral Reef Conservation Program established an integrated and focused monitoring effort with partners across the United States—the National Coral Reef Monitoring Program. Coral reef monitoring data can help to inform science-based management decisions about these invaluable natural resources. These findings are shared with local agencies, partners, and communities to inform both federal and local management strategies.

The Archipelagic Research Program at the Pacific Islands Fisheries Science Center helps in these efforts. This team surveys coral reefs at more than 40 islands and atolls throughout the Pacific ocean.

To be consistent at a national scale, the goals of the National Coral Reef Monitoring Program are to:

Develop consistent and comparable methods to survey indicators of coral reef health and climate change
Build and maintain strong partnerships with federal, state/territory, and academic partners
Collect scientifically sound biological, climate, and socioeconomic data in U.S. coral reef areas
Deliver high‐quality data, data products, and tools to the coral reef conservation community
Provide context for interpreting results of localized monitoring
Share periodic assessments of the status and trends of the nation’s coral reef ecosystems

Where We Monitor

American Sāmoa
Hawai‘i, including the Papahānaumokuākea Marine National Monument
Mariana Archipelago: Guam and the Commonwealth of the Northern Mariana Islands
Pacific Remote Island Areas: Wake, Johnston, Howland, Baker, and Jarvis Islands, and Palmyra and Kingman Atolls

A map of the Pacific ocean with several archipelagos highlighted. — The islands and archipelagos that are surveyed by the National Coral Reef Monitoring Pacific team. Credit: NOAA Fisheries

What We Monitor

Fish

Scientists dive beneath the ocean surface to observe reef fish populations. These are non-extractive surveys, meaning no fish are taken. Scientists count and measure the size of fish that inhabit the coral reef. The abundance and distribution of reef fish helps us determine the condition of the ecosystem.

4000x3000-REA-survey-caranx-sexfasciatus-PaulaAyotte.jpg — Diver conducts rapid ecological assessment of reef fish as a school of bigeye trevally (Caranx sexfasciatus) swim by. Credit: NOAA Fisheries/Paula Ayotte

Corals

Monitoring corals at the same locations over time provides valuable information on their resilience to local and global threats. It allows scientists to see if corals are growing or shrinking, and if they are showing signs of stress or disease. Our hope is for the corals to grow or remain the same, so that coral reefs can persist through time.

A diver hovers over a pink hued reef while preparing a camera to take images of the benthos. — Chief Scientist, Dr. Courtney Couch, prepares to take digital photographs of the reef surface in the shallows off Swains Island. She will snap over 1,500 overlapping pictures along the transect line, despite the wave energy pushing her left and right. Back in the office in Honolulu, our team will use these images to create a large-scale, 3D model of the reef ---a technique called 'structure-from-motion'. From this model, our scientists will count, identify the species, and assess the condition of the corals on the reef from the comfort of their chairs! Credit: NOAA Fisheries/Mia Lamarind

Ocean Conditions

Scientists also measure water temperature, salinity, and carbonate chemistry. They also measure other physical characteristics of the coral reef environment such as coral growth and erosion. Using all these measurements, researchers can assess the potential early effects of ocean acidification on corals. As oceans become more acidic, corals can erode at a faster rate, making it vitally important to monitor.

Over-under shot of a scientist pulling up instruments from a small boat — Scientists collect water samples in between dives. The package of electronic instruments is carefully lowered to hover above the reef, recording conductivity, temperature, and depth data one meter below the surface. Photo: NOAA Fisheries/Andrew Gray

How We Monitor

To track biological trends and monitor climate-driven impacts, we use the same suite of survey methods at each island they visit. Over time, scientists can see how they have changed—an important part of reef conservation. We gather data by:

Assessing reef fish populations by identifying, counting, and estimating their size during underwater surveys—no fish are taken during these surveys
Collecting thousands of photographs of corals to create three-dimensional images—these models are used to measure coral colony changes
Using underwater temperature recorders, collected seawater samples, and coral growth plates to assess the status of ocean acidification and warming on coral reef health

What We Learn

After collection and a thorough review process, data is shared with local management agencies and the public. This data gives us a snapshot of coral reef health and is presented in status reports, used to answer questions from local resource managers. They provide a valuable time series. These long-term surveys across a wide variety of reefs gives us power to understand the drivers of reef health and help us predict future impacts. Check out a visualization tool of our previously collected data.