Hawaii's Coral Reefs Help Protect Shorelines and Support Marine Life

A 2025 USGS study and field measurements around Molokai report that Hawaii's fringing coral reefs — part of more than 410,000 acres of reefs in the state — can reduce wave intensity by as much as 80%, and that reef health affects how much wave energy reaches the shore.

Hawaii's coral reefs are widely known for their color and marine life. They also play a practical environmental role along many island shores. A 2025 U.S. Geological Survey (USGS) study and field measurements on Molokai examined how fringing reefs respond to strong waves and storm surges. These findings are discussed alongside observations about reef health and human impacts. Key findings: - Hawaii contains more than 410,000 acres of coral reefs, about 85% of reefs in the United States. - A USGS hydrodynamic field experiment on Molokai, using data from 2018 storm events, reported that fringing reefs reduced wave intensity by up to 80% before waves reached the shoreline. - Fringing reefs are the predominant reef type in Hawaii, and the reported results indicate that reef condition influences how much wave energy the reef crest absorbs. - The article notes human activities have affected reef condition; for example, the reef at Hanauma Bay showed notable improvement during a period of closure in the early COVID-19 pandemic. - Chemical sunscreens and direct physical contact with coral were reported as factors linked to reef damage in the discussion. Summary: The USGS study and related observations underscore that Hawaii's coral reefs contribute measurable coastal protection while supporting diverse marine life. Researchers report that the protective effect depends on reef condition, and how that service will change as environmental pressures continue is undetermined at this time.