About Coral Bleaching…Videos & More

By now, most of us who live in and love Hawai‘i have heard that the islands are in the midst of another severe coral bleaching event. Coral bleaching occurs when seawater becomes too warm, causing corals to expel microscopic algae living in their tissue that are their primary food source and give them their pigment. This is the second mass bleaching event in Hawai‘i in just four years, and the trend of increasing global temperatures is expected to continue. There is, however, a glimmer of hope: research and qualitative observations indicate that the more we reduce additional stressors, the more resilient coral can become to the more frequent and intense thermal stress events that are expected moving forward.

Convict tang swim by a healthy cauliflower coral head in Kahalu‘u Bay

For more than 15 years, we’ve had a near-daily presence at Kahalu‘u Bay and Beach Park on Hawai‘i Island’s leeward coast. Through our Kahalu‘u Bay Education Center (KBEC), our staff and ReefTeach community stewards engage with tens of thousands of visitors and residents each year, educating them with aloha on how to enjoy and protect the bay’s vibrant and colorful marine ecosystem by avoiding direct contact with coral reefs and wildlife. Last year we also began to promote reef-friendly sun protection in an effort to reduce the amount of sunscreen chemicals entering the bay. Yet despite our best efforts, we are witnessing coral decline in our beloved bay due to additional, increasing stressors. For corals at Kahalu‘u and across the Hawaiian Islands to have a chance at overcoming this year’s and future bleaching events, we all need to pitch in to adopt reef-friendly behaviors and encourage our friends, families, and visitors to do the same.

“Reducing additional stressors isn’t guaranteed to save our coral reef ecosystems in the long run,” says Kathleen Clark, marine stewardship and education specialist at KBEC, “but it can definitely buy us more time as we and researchers continue to investigate long-term strategies and solutions. Coral reefs are the backbone of our marine ecosystems, so it’s critical we do all we can to care for them.”

Here are six simple actions we can all take to reduce stress on our marine ecosystems:

1. Cover up: Protect yourself, protect the reef
Protecting ourselves from the sun is very important, and how we do so can have a significant impact on water quality and the health of our aquatic ecosystems. Choosing mineral-based sunscreens can help, but the best way to support coral and marine health is to keep our ocean free of any substances that wouldn’t naturally be found there in the first place. The healthiest choice we can make for the environment—and ourselves—is simply to cover up. Wear hats, wraps, rash guards, board shorts, anything light that will keep you cool and shielded from prolonged UV exposure. Then apply a modest amount of mineral-based sunscreen where you need it. With mineral-based sunscreens, a little goes a long way.

WATCH: “How to apply mineral-based sunscreens”
(Stream2Sea, 3 minutes, 37 seconds)

Oxybenzone, an active ingredient in many sunscreens, has been shown in laboratory tests to contribute to declines in reef health by disrupting coral growth and reproduction. Octinoxate, octocrylene, nanoparticles, and a host of other chemicals commonly found in sunscreens are known or suspected to have similar effects. Because these chemicals wash off in the shower, are absorbed into our skin, and excreted in urine, they can still find their way into the ocean, even if we’re not at or near a beach.

If you must use sunscreen, picking a reef-friendly product is easy: look on the back at the active ingredients. Sunscreens with natural bases that list zinc oxide and/or titanium dioxide as the only active ingredients are your best bets. Be careful, though: many sunscreens will say “reef-friendly” on the bottle but contain ingredients that aren’t, so it’s always best to review the active ingredients.

READ: Is Your Sunscreen Actually Reef-Safe? (Honolulu Civil Beat)

2. Always avoid contact with the reef
Corals are fragile, and even the slightest touch can affect their health and well-being. When enjoying a day in the water, take care not to stand on, step on, touch, or kick corals and even rocks. Stay afloat! If you must stand, it’s best to find a sandy spot. Also, please give honu (green sea turtles), fish, and other marine life plenty of space and don’t touch, chase, or feed them.

Left: A snorkeler at Kahalu‘u Bay stays afloat above the coral reef.
Right: Snorkelers standing on rocks and rubble, damaging and even killing new coral growth.

3. Reduce chemicals and pollutants that can make their way into waterways
No matter where we are in Hawai‘i, we’re never very far from the ocean. That means pollutants such as pesticides, herbicides, fertilizers, untreated sewage, solvents, motor oil, gasoline, and the like can easily make their way ma kai (toward the sea), winding up in our marine ecosystems. Increased levels of nitrogen in ocean waters are contributing to higher rates of coral bleaching and disease worldwide. We must take great care to use, contain, and dispose of hazardous materials properly, and have our vehicles inspected for leaks to keep fluids off our roadways. If you’re on Hawai‘i Island, learn how and where to dispose of hazardous materials (including electronics, batteries, and medications), and if you’ve got chemical-based sunscreens you’d like to get rid of responsibly, we can help you with that.

WATCH: What’s killing coral in the Florida Keys? Scientists say it’s more than just rising temperatures (NBC News, 2 minutes, 15 seconds)

4. If you like to fish, spare the herbivores
Corals are dependent on fish like uhu (parrotfish), manini (convict tang), kala (unicornfish), kole (spotted surgeonfish), and other herbivorous reef fish that eat algae that can proliferate, overtake, and smother coral reefs when ocean temperatures are elevated. Uhu are also responsible for making sand, playing another crucial role in ecosystem maintenance. Whether we’re fishing for supper, perusing the seafood aisle at the grocery store, or ordering at a restaurant, we can choose more sustainable alternatives to reef-dwelling herbivores, such as opah or wild salmon. It’s also a good idea to avoid certain species during their spawning seasons. Check out our Spawning Guide for the Leeward Coast of Hawai‘i Island, as well as websites like FishWatch.gov and EWG’s Consumer Guide to Seafood.

5. Learn more about reef conservation, then educate others
The more we know about how marine ecosystems function and the threats they are facing, the more we can teach our families, friends, neighbors, and visitors, and inspire them to adopt positive stewardship behaviors. Through our ReefTeach program at Kahalu‘u Bay, we learn from the coral reefs themselves, as well as scientists and marine conservation experts, and share that knowledge with community members at free ReefTeach orientations and through friendly, on-site interactions with visitors to the bay each and every day. Contact us to find out about upcoming orientations or to join our team of ReefTeach community stewards.

ReefTeach community stewards educate visitors to Kahalu‘u Bay about how to enjoy the bay while minimizing harm to its fragile marine ecosystem

6. Make your voice heard
If you’re concerned about the health of our oceans, coral reefs, and marine life, contact your county, state, and federal legislators and agencies and respectfully encourage them to enact policies that protect and enhance water quality and ecosystem health. From sunscreen chemicals to cesspools to overcapacity at popular ocean recreation spots, there are a host of issues on which decisionmakers can take action. Whether it’s writing or calling our representatives, submitting testimony, or casting a ballot, we can influence public policy—the more of us, the better.

“We must all accept the kuleana (responsibility) to take care of place, our planet, and do the best we can to protect our precious natural resources,” says Cindi Punihaole, director of our Kahalu‘u Bay Education Center. “By staying the course, we can achieve positive change for Kahalu‘u Bay and for all of Hawai‘i’s coastal ecosystems and beyond. I ka lokahi kō kākou ka ola ai—the well-being of all of us is in our unity.”

Residents and visitors who observe coral bleaching in Hawai‘i’s ocean waters are encouraged to report their sightings on the Hawai‘i Coral Bleaching Tracker website at hawaiicoral.org. Data are reported to the State of Hawai‘i weekly, and will help researchers devise responses in critically impacted sites and increase our understanding of coral bleaching moving forward.