The state Department of Land and Natural Resources is saying many coral colonies affected by a recent bleaching event on Kaua‘i and other Main Hawaiian Islands are now showing signs of recovery.
Last fall, a coral bleaching event caused by ocean temperatures as high as 86 degrees Fahrenheit affected coral colonies in shallow waters off Kaua‘i, O‘ahu and Maui. Bleaching is a stress response, which causes corals to lose algae and color from their tissue, making them appear snow white.
“In general, coral can recover from bleaching but it can take weeks to years for a coral reef to fully recover,” said Anne Rosinski, a marine resource specialist with the DLNR Division of Aquatic Resources. “In recent weeks, teams from DAR and the Hawai‘i Institute of Marine Biology have seen color and life returning to corals, but they’ve also documented areas of dead coral and white, bleached coral.”
However, temperatures are predicted to become dangerously warm for corals again in 2015, according to DLNR. Bleaching is forecasted to happen during the time of highest sea temperatures from July-October. Globally, coral bleaching is expected to become a more common phenomenon in coming decades.
“I think in general around Kaua‘i we are starting to see a recovery,” said Kaua‘i DAR Education Specialist Katie Nalesere. “The sea surface temperature has dropped about 5 degrees since our initial assessments.”
Nalesere said she believes people are becoming more aware of how actions on land have a direct impact on life in the ocean. She and her DAR colleagues continue to encourage people to practice sustainability and to reduce their carbon footprints to help combat coral bleaching and diseases associated with climate change and land use practices.
Darla White, Maui’s DAR special projects coordinator, said the DLNR has tagged and numbered coral colonies so they can find them each time.
“We tagged both bleached colonies and colonies that have a tissue-loss disease; a high mortality disease that we anticipate may worsen if coral bleaching consistently occurs in the next couple of years,” White said. “We are going to continue following these corals to understand whether or not they are going to bleach again, and if so, will they be more susceptible to disease thereafter.”
As on Kaua‘i and Maui, the recovery report for O‘ahu is a mixed bag, according to DLNR.
After an assessment trip onto patch reefs in Kaneohe Bay, DAR aquatic biologist Stacy Bierwagen said she thinks the general consensus has been that everything in Kaneohe Bay that is recovering is going to stay recovered at this point.
“What we are wondering about in the future is if the corals that have recovered will do so again after the next bleaching event, or will it be worse for them?” she said.
In 2014, bleaching was also observed on several reefs of the Northwestern Hawaiian Islands, and scientists will be returning to those locations in the summer of 2015 to find out whether those bleached corals have recovered.
During the 2014 bleaching season, DAR received more than 100 reports from ocean users and 60 photographs of bleaching from across the state, which helped monitoring teams to find and assess bleached coral areas.
The DLNR encourages anyone who observes bleaching to report it and, if possible, send pictures to www.eorhawaii.org.
Visit http://dlnr.hawaii.gov/reefresponse for updates and scientific data from the 2014 bleaching event.