A recent study reports the largest known mass mortality of coral reefs to be recorded in Guam in the last five centuries.
In a study published online in the journal Coral Reefs, researchers reported that several coral bleaching events driven by above-average sea temperatures killed off more than one-third of all coral reefs in Guam and up to 60 percent of corals along Guam’s eastern coast from 2013 to 2017.
Reefs in the CNMI have not been spared either.
The National Oceanic and Atmospheric Administration, which has been monitoring the health of CNMI coral reefs, reports that the biggest threat and majority of reef deaths that NOAA has seen on Saipan’s reefs were caused by extremely warm waters that occurred in 2013, 2014, and 2017.
Other findings show that the deterioration of the CNMI reefs were also caused by factors such as typhoons and man-made activities.
“Typhoon Soudelor and [Super Typhoon] Yutu did cause some direct damage to reefs, resulting from big waves and rough seas, particularly on the east and south sides of the island, but the biggest impacts to corals from the storms is probably all of the marine debris,” said Kaylie Costa, a NOAA Hollings scholar and an incoming senior at the University of Miami.
Even now, a large amount of building materials like roofs and green debris such as tree limbs can still be found both in the lagoon and out on the forereefs, she said.
“We also see impacts from divers and snorkelers at some of our tourist destinations,” she said, although the diver-specific impacts are limited mostly to the roped entry and exit routes at Laolao Bay and Obyan Beach.
On Managaha Island, snorkelers have flattened most of the nearshore corals by standing on them, she added.
There is also evidence that people have been feeding the fish at these tourist spots, Costa said. Feeding the fish changes their behavior and can cause an imbalance in the local ecology.
There is also some concern that overuse of these areas may be contributing to some of the red flags, for example, high bacteria counts, which is visible at the Grotto and some other high-use beaches.
Costa that the coral reef restoration program in the CNMI is still in the developing stages and the many challenges it faces—protecting, propagating, and nurturing coral reefs in the CNMI—is made more difficult by the CNMI’s remoteness and lack of a readily available SCUBA-certified labor force, especially when the coral reef nursery grows beyond what can be managed by a small team.
“Cleaning and out-planting…are relatively dirty jobs that many nurseries achieve through partnerships with universities or specialized volunteer groups but the CNMI doesn’t currently have an equivalent,” she said.
“…We are hoping to be able to scale up our efforts in the near future, using corals that have survived the recent bleaching events and are therefore more resilient to thermal stress,” she said.
That would include creating a volunteer program to get the community involved in the nursery, training volunteer divers and snorkelers to help with nursery maintenance, including removing algae and propagating corals, as well as out-planting activities.
The public can help preserve coral reefs by spreading the word about the importance of coral reefs, introducing more eco-friendly practices into their daily lives, and practicing reef-safe diving practices.