Monitoring the Health and Resilience of Lāhainā’s Coral Reefs
Why was monitoring Lāhainā’s coasts urgent? In August 2023, the west-Maui town of Lāhainā was devastated by a wildfire. Though people are typically familiar with how wildfires influence terrestrial ecosystems, much less is known about how they influence marine ecosystems. Following the fire, residents and managers wanted to know if runoff from land was impacting the reef and whether there would be lasting effects.
Though there are many methods to test for reef health, one simple way is to assess whether the reef is calcifying and building on itself. Total alkalinity, a simple chemical parameter measuring the pH, or acidity, of a water sample, can be reasonably indicative of the health of a stretch of reef in a big-picture assessment. This was only one portion of the monitoring conducted in Lāhainā’s waters over the following year and a half.
How do we get that information? As part of a collaborative effort with federal agencies, state organizations, and local residents, a team of faculty from UH Mānoa (including Andrea Kealoha, Craig Nelson, Nick Hawco, and Eileen Nalley) assembled to sample along the coastal reefs and monitor their microbial communities, trace metals concentrations, contaminant concentrations in reef fish, carbon chemistry, and nutrient levels. The main goal was to establish a baseline of local reef health and create environmental health references as the area was rebuilt.
Why is this helpful? The research showed that while land typically takes a while to recover, the ocean was quite resilient. While specific locations like the harbor saw slower recovery due to the sheer volume of pollutants (e.g., lead paint, electrical components, and fuels coming from destroyed boats), areas connected to open ocean were doing better than expected.
Dr. Sam Kekuewa, a PICCH researcher working on this project, commented on the importance of water quality monitoring: “If we want to know how our ecosystems will behave in the future, we need to know what’s happening to them now. We won’t know if a reef is healthy unless we observe it, and it’s hard to observe every single thing on a reef. It would take too much manpower and time to go to each and every coral. But by monitoring water quality, we can look at a larger system more efficiently and more effectively. What happens on a reef is communicated in the water quality. It’s the most effective methodology to observe the health of an aquatic ecosystem.”
For more information on this project, watch the Voice of the Sea episode featuring this project: (check back after the release date in June, 2026).
