HAGATNA, Guam — Vulnerable coral reefs around Guam have not experienced the severe bleaching that was predicted for this year, in part because of stormy weather that reduced water temperatures.
The Guam Bureau of Statistics and Plans said a mass coral bleaching event indicated by satellite measurements of sea surface temperatures did not occur.
“We have so far been very lucky,” said Whitney Hoot, a coral reef resilience coordinator with the statistics and plans bureau.
The National Ocean and Atmospheric Administration’s Coral Reef Watch program indicated in July that the island would likely experience significant bleaching, which often precedes coral death.
Recent stormy weather including Super Typhoon Hagibis may have contributed to the coral’s survival through cloud cover that cooled surface water temperatures. Storms and wind are also likely to have exchanged hot water in shallow areas with cooler water from deeper areas, officials said.
Coral paling, which is the precursor to bleaching, has affected some corals, and the island is still under a bleaching warning, which is anticipated to remain for up to four weeks, Hoot said.
“If we were expected to stay at the warning level for a long time, I would be more concerned about the impacts of the ongoing thermal stress,” Hoot said. “But since the warning status should end soon and we’re not expected to reach alert level one or alert level two, we are hopefully going to avoid severe bleaching this year.”
While severe bleaching is no longer expected, the reefs “are still at risk from local stressors — over-fishing, pollution, physical damage from groundings, and human users,” Hoot said.
