Coral Bleaching Threatens Hawaii’s Coastline

Mar 1, 2018 | General Information

The health of coral reefs is more important than most people realize. Not only are coral reefs essential to healthy coastlines but also to healthy coastal economies, literally supporting thousands of businesses. Coral reefs protect coastlines from erosion by absorbing wave energy. Climate change, pollution and fishing have made coral an endangered species.

Think of coral reefs as marine rainforests that house and nurture at least 25 percent of the planet’s marine species. Over the past three decades as much as one-quarter of the world’s live coral has been lost. When corals are stressed by changes in conditions such as temperature, light, or nutrients, they expel the symbiotic algae living in their tissues, causing them to turn completely white. This is called coral bleaching. Mass bleaching of coral has been driven by ocean warming. When a coral bleaches, it is not dead. Corals can survive bleaching, but they are under more stress and at risk of mortality.

Many of us have heard about mass bleaching of Australia’s Great Barrier Reef. Bleaching has killed more than 30 percent of the Great Barrier Reef’s shallow water corals. Likewise for coral reefs in the Seychelles located in the Indian Ocean. Researchers also are warning that warming ocean waters in the Pacific could spell disaster for coral reefs along the southwest coastline of Hawaii’s Big Island. There are growing concerns a marine heat wave could be even worse than the catastrophic event in 2015 that killed nearly half of the coral along the Big Island’s coastline. Hawaii is still recovering from that event and thus is more susceptible to thermal stress. Record ocean temperatures around Hawaii in 2019 were increasing that stress.

What can tourists do and not do to prevent more coral damage in Hawaii? The National Oceanic and Atmospheric Administration (NOAA) is advising both tourists and locals to:

avoid killing parrotfish, surgeonfish and other herbivores because they clean coral as they nibble algae all day;

use reef-safe sunscreen;

keep anchors away from reefs;

dispose of chemicals like fertilizers and oils properly;

do not stand on any reef.

As for sunscreens, be aware that some sunscreens include chemicals that destroy coral. Sunsceen’s chemicals induce coral bleaching. Research studies show that sunscreen washing off swimmers annually in oceans worldwide is destroying as much as 10 percent of coral reefs. Chemicals in sunscreen can also be toxic to fish. Protect fragile reef ecosystems by avoiding sunscreens that contain four ingredients that have been linked to coral bleaching: oxybenzone, butylparaben, octinoxate and 4-methylbenzylidine camphor. In addition, apply sunscreen about 15 minutes before you head into the ocean so the sunscreen has a chance to soak in.

Enjoy what the sea-world of Hawaii offers and, at the same time, do your best to protect that marvelous sea-world, too.