Evaluating Recovery of West Hawai‘i Reefs Eight Years Post-bleaching
This report assessed previously-surveyed reefs in West Hawai‘i eight years after the 2015 mass bleaching event and estimated resistance, recovery and net change using timeseries data. The study found little measurable recovery since the 2015 event, suggesting that severe bleaching events occurring every few years would increase the likelihood of a gradual yet continuous degradation of reefs in West Hawai‘i.
Subject Tags
- Climate resilience
- Reefs
- Climate adaptation
Introduction
This report evaluates the recovery and resilience of coral reefs along the west coast of Hawai‘i Island eight years after the severe 2015 mass bleaching event. Surveys conducted in 2023 across 20 reef locations assess changes in coral cover, benthic composition, and fish biomass. Results show that coral cover increased compared to earlier post‑bleaching years and no longer significantly differs from pre‑bleaching levels, although recovery remains uneven across sites. Turf algae and abiotic substrates declined while reef‑building corals and crustose coralline algae increased, indicating a positive recovery trajectory. Fish biomass remained lower than pre‑bleaching levels and exhibited high variability. The study finds that recovery processes are more important than resistance in determining reef resilience, and that resilience rankings developed prior to bleaching were poor predictors of observed outcomes. Findings highlight the importance of improving reef recovery processes and addressing climate‑driven stressors to sustain coral reef ecosystems.
Suggested Citation
Minton, D., Barnwell, M., Carr, R., Grady, B., Lynch, H., Most, R., Schem, J., & Conklin, E. 2025. Evaluating Recovery of West Hawai‘i Reefs Eight Years Post-bleaching. The Nature Conservancy. Honolulu, HI. 43 pp.
TNC Authors
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Mikayla Barnwell
Coral Restoration Specialist
The Nature Conservancy
Email: mikayla.barnwell@tnc.org -
Ryan Carr
Marine Monitoring Manager, Hawai‘i
The Nature Conservancy
Email: rcarr@tnc.org -
Bryant Grady
Marine Data and Restoration Project Manager
The Nature Conservancy
Email: bryant.grady@tnc.org -
Harry Lynch
Marine Field Operations Manager
The Nature Conservancy
Email: hlynch@tnc.org
TNC Authors
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Jess Schem
Marine Monitoring Science Specialist
The Nature Conservancy
Email: jess.schem@tnc.org -
Eric Conklin
Marine Science Director, Hawai‘i and Palmyra
The Nature Conservancy
Email: econklin@tnc.org