Maui Surveys Aimed at Improved Prediction of Bleaching and Disease Risks for Hawaiian Coral Reefs

Among the expected effects of climate change on coral reefs are higher levels of thermal stress caused by ocean warming. Temperatures above a critical threshold increase the risk of coral bleaching. The bleaching not only leads to reduced coral abundance and productivity, but makes coral more susceptible to disease.

Anomalous and discolored growth protuberances were observed on the rice coral Montipora capitata 
            during April surveys off the coast of Maui. NOAA photo by Bernardo Vargas-Ángel.
Anomalous and discolored growth protuberances were observed on the rice coral Montipora capitata during April surveys off the coast of Maui. NOAA photo by Bernardo Vargas-Ángel.

To learn more about these processes, researchers in the PIFSC Coral Reef Ecosystem Division (CRED) partnered with the Hawai'i Division of Aquatic Resources to conduct a series of coral disease surveys in April and July 2010 at several locales around the island of Maui, in the main Hawaiian Islands. The joint project "Environmental Monitoring of Coral Bleaching and Disease in the Hawaiian Islands" aims to improve understanding of the occurrence, abundance, and outbreak of coral bleaching and disease in the Hawaiian Islands through expanded field surveys and collection of temperature data in situ and from remote sensors. A primary research goal is develop an experimental tool to predict the risk of coral bleaching and disease in the region using sea surface temperature data collected by satellite-borne remote sensors.

During April, surveys were conducted along the shoreline at 4 west Maui sites: Molokini crater, Keawakapu, Kahekili, and Honolua Bay. Other Maui locations were surveyed during July: Honolua Bay, Mahaina-haina, Kahekili, Puamana, Olowalu, Ma`alaea Harbor, Keawakapu, Molokini crater, Ahihi-Kinau, Kanahena Bay, and Kanahena Point.

Data collected in the recent Maui surveys are expected to provide a better understanding of the intra-annual patterns of coral bleaching and disease prevalence at the selected sites. Comparable surveys are planned for areas around the islands of Hawai'i and O'ahu.

The project is led by CRED coral disease specialist Bernardo Vargas-Ángel with funding from NOAA's Coral Reef Conservation Program.