LIHUE — Scientists say higher-than-normal sea surface temperatures are threatening corals around Kauai.
“I haven’t seen an event like this,” said Christina Runyon, a graduate research assistant at University of Hawaii’s Institute of Marine Biology.
Runyon spent the last two weeks surveying reefs on Kauai’s north, east and south facing shores, and found coral bleaching at 10 locations. While prevalence and severity varies at each location, all are experiencing some level of coral bleaching, which is a stress response resulting from warmer ocean temperatures that cause corals to lose the color from their tissue, often turning white.
Bleaching can also kill coral.
Don Heacock, Kauai District fisheries biologist for Department of Land and Natural Resources, said corals are the “canaries in the proverbial oceanic coal mine,” and that bleaching is an indication that humans have fooled around with the environment too much.
“We should all be aware that this is our home and these coral reefs protect our shoreline. If they go, a lot of us go,” he said. “Our corals are saying, ‘Something is wrong.’”
The two options, Heacock said, are to listen or turn our backs.
“If we lost our coral reefs our coastal fisheries production would drop by an order of magnitude or more,” he said. “We have to protect them.”
Runyon described the situation on Kauai as sad and unfortunate.
“Global climate change is showing itself to us right now,” she said. “We are starting to see (ocean) temperatures that are 1 to 2 degrees higher than what we normally see.”
The surveys included three locations at Anini, as well as Ahukini, Koloa Landing, Salt Pond, Naue/Charros, Limahuli, Hana Honu (south of Larsen’s) and Moloaa Bay. The types of corals impacted by the bleaching event are mound, finger, rice and small/branching corals.
Among the hardest hit areas is Moloaa Bay, on Kauai’s northeast shore, where between 51 and 75 percent of the live coral has been bleached, according to reports filed by Runyon and Katie Nalesere, education specialist for the Department of Land and Natural Resources’ Division of Aquatic Resources, as part of the Eyes of the Reef Network.
Ahukini and Hana Honu are each showing between 31 and 50 percent coral bleaching, according to the reports.
Anne Rosinski, DAR marine resource specialist, said DAR staff has been working with staff from the Papahanaumokuakea Marine National Monument and has been in the water at multiple locations on Kauai to visually survey coral bleaching.
“DAR staff reported variability in the extent and severity of coral bleaching at surveyed locations on Kauai,” she wrote in an email response Monday. “Corals ranged from unaffected to pale to bleached white.”
Rosinski added that bleaching conditions are projected to continue and worsen in the next four to six weeks, and that DAR staff will continue collaborating with other agencies to monitor conditions around Kauai.
News of the Kauai bleaching event comes just one week after the DLNR announced via a news release that its Division of Aquatic Resources Rapid Response Team was responding to above-normal levels of bleaching at numerous near-shore locations on Oahu.
Runyon said she was surprised that she hadn’t heard more reports of the Kauai event prior to arriving on island early this month to begin her surveys.
“Corals can recover from bleaching if temperatures return to a normal range, but it can take many weeks to many years for them to fully recover from a bleaching event,” DLNR Chair William J. Aila Jr. said in a release.
Heacock said one thing that may have contributed to the current event is the recent full moon coupled with extreme high and low tides, which exposes shallow-water corals to warmer waters.
Local marine biologist Katherine Muzik said she has seen bleaching from the reef fronting the Kapaa Library down to Waipouli.
“This is very depressing,” she said.
Lately, Muzik said she feels helpless while out in the water — that fighting forces as big as rising ocean temperatures and global climate change are simply out of reach.
“It’s really warm,” she said of the water. “And the corals just confirmed it.”
The National Oceanic and Atmospheric Administration’s Coral Reef Watch program has continued a high coral bleaching alert for waters around the Hawaiian archipelago. The warnings are based on indicated high sea surface temperatures, resulting in a high likelihood for bleaching.
Moderate to severe coral bleaching has also been observed in Papahanaumokuakea National Marine Monument, co-managed by state and federal partners.
The DLNR encourages ocean users to report coral bleaching through the Eyes of the Reef Network, eorhawaii.org, which helps the DAR Rapid Response Team evaluate reef conditions and inform best management options. The department encourages anyone with underwater cameras to send photographs of bleached corals to RRCPCoordinator@gmail.com.
The NOAA Coral Watch prediction tool may be viewed at coralreefwatch.noaa.gov/satellite/index.php
Chris D’Angelo, environment writer, can be reached at 245-0441 or email@example.com.