Even though they still provide some habitat, dead staghorn
colonies will soon collapse to rubble and fish will go elsewhere.
Guam’s reefs have had a tough go of it in the past four years. That’s because Guam and other Mariana and Micronesian islands have been affected by the longest global coral bleaching event on record. The western Pacific is not alone. It has been impacting reefs around the world for three years. In 2017, there is hope it is finally coming to an end. However, Guam is not in the clear yet.
“For 2017, we are holding our breath” says Laurie Raymundo, PhD, from Guam’s UOG Marine Lab. She and her colleagues have been monitoring the corals around the island for the duration of this bleaching and she says Guam has definitely lost some coral cover as a result. Both hard and soft corals have been affected as well as sea anemones and other coral-related creatures.
Why is this a big deal? Coral reefs perform numerous important tasks including protecting coastlines from storms waves and erosion, provide fish habitat, provide nitrogen and nutrients as part of the ocean’s food chain and they are among the most complex eco-systems in the world.
On Guam and most of Micronesia they also aid in tourism, the largest industry in the islands. People come from far and wide to see the corals and fishes and enjoy the warm waters in the islands. Also, without reefs, fish have no place to spawn and safely grow. The fishing industry gets impacted for both sport fishermen and commercial fishers.
Bleached soft corals in north Tumon Bay show that not only hard
corals are affected by the El Ninos.Soft coral, sea anemones and
other coral-related creaures also struggle in these conditions.
Coral bleaching occurs when ocean temperatures increase. When the waters get too warm, corals spit out the algae that live inside. Normally, these algae provide corals with most of the energy they need to live. Corals that have lost their algae are sick and are white-looking or “bleached” because the algae give healthy corals their bright colors. Soft corals sometimes turn a brilliant yellow, which is pretty to see but a real sign they are fighting for their lives. Sea anemone tentacles also turn white as they struggle to live.
Raymundo says Guam’s corals have had certain degrees of damage. Some colonies, especially in the staghorn family, have totally died out in some spots. While fish may still be living in the dead coral structures, sooner or later these stands will collapse and fish will move elsewhere. Other have exhibited the “Phoenix Effect” where some, but not all, of the colony dies. The remaining corals regrow and try to take hold again. This can be seen in many areas in Guam’s Tumon Bay Marine Preserve, especially at the south end. Affected soft corals can be seen farther north near the Westin Cut.
“Right now we are on Watch status” says Dr. Raymundo for the upcoming months of 2017. NOAA, the National Ocean and Atmospheric Administration issues Alerts, Watches and Warnings (a Warning is the worst) regarding the reefs. Starting in late July through August and September Guam may see the waters warm up. Although coral bleaching is no longer affecting reefs worldwide, forecasts show that Guam’s reefs may still bleach this year.
Citizens can help Guam’s coral reefs. Helping keep places like Tumon Bay clean by wearing protective swimwear as opposed to sunscreen is one way to help. Sunscreen can float and get on corals and damage them. Not urinating in the bay also helps. Females on birth control can release hormones that also may inhibit coral growth. Keeping petroleum products and plastics from entering our coastal waters also helps. With the corals already fighting for survival, the cleaner the water, the better to aid corals in their fight.
There is a program called Eyes of the Reef. It provides training to learn to identify coral bleaching and report it online at EORMarianas.org. Eyes of the Reef is an important part of Guam’s early warning system for coral reefs, as reports from participants allow local scientists and managers to take action quickly and effectively.
Healthy corals in Tumon thrived on nutrients and currents prior to recent years of bleaching.
Photos: Tim Rock
Tim Rock, an author and photographer, has been a prominent member of Guam’s underwater community since the 1980s.