Ocean warming
Marine heatwaves can cause coral bleaching and mortality.
Science & recovery
Protection is an experiment we can measure.
Kahekili was created after years of coral decline and recurring algal blooms. Scientists began monitoring before the 2009 rules took effect, giving the area unusual value as a long-term reef study.
The problem
Coral loss and too much algae
At monitored North Kāʻanapali sites, coral cover fell from about 55% in 1994 to 33% in 2006. Reduced abundance of herbivorous fish and persistent macroalgal blooms helped motivate a targeted strategy: protect the animals that naturally graze the reef.
What changed after 2009
A six-year study found strong increases in the biomass of protected fishes inside Kahekili, especially parrotfishes. By 2014–15, parrotfish biomass had increased by 139%. Researchers also observed more crustose coralline algae—an important surface for reef building and coral recruitment—while similar changes were not detected in unprotected fish groups.
Kahekili shows that targeted fisheries management can restore an ecological process: grazing. It does not make the reef immune to warming, pollution, storms or other stress.
The bigger picture
Grazing is necessary. It is not sufficient.
Land-based pollution
Nutrients and sediment can favor algae and reduce reef resilience.
Physical damage
Standing, anchors, careless fins and debris can break slow-growing coral.