Threats to Hanauma Bay

For local residents and to thousands of visitors each year, Hanauma Bay provides an opportunity to enjoy one of nature’s most splendid creations. This, however, has not come without costs. In addition to its beautiful white sands, waters of blues and turquoise, and gorgeous blue skies, Hanauma Bay also shelters a living coral reef, part of the global infrastructure of vital coral reef systems.

Coral reefs are diverse underwater ecosystems held together by calcium carbonate structures secreted by corals. Coral reefs are built by colonies of tiny animals found in marine water that contain few nutrients. Most coral reefs are built from stony corals, which in turn consist of polyps that cluster in groups. The polyps belong to a group of animals known as Cnidaria, which also includes sea anemones and Jellyfish. Unlike sea anemones, corals secrete hard carbonate exoskeletons, which support and protect the coral polyps. Most reefs grow best in warm, shallow, clear, sunny and agitated water. Often called “rainforests of the sea”, shallow coral reefs form some of the most diverse ecosystems on Earth. They occupy less than 0.1% of the world’s ocean surface, about half the area of France, yet they provide a home for at least 25% of all marine species, including fish, mollusks, worms, crustaceans, echinoderms, sponges, tunicates, and other cnidarians. Paradoxically, coral reefs flourish even though they are surrounded by ocean waters that provide few nutrients. They are most commonly found at shallow depths in tropical waters, but deep water and cold water corals also exist on smaller scales in other areas. Coral reefs are fragile ecosystems, partly because they are very sensitive to water temperature. They are under threat from overtourism, climate change, ocean acidification, blast fishing, cyanide fishing for aquarium fish, sunscreens containing oxybenzone, octinoxate and other chemical sunscreen filters, overuse of reef resources, and harmful land-use practices, including urban and agricultural runoff and water pollution, which can harm reefs by encouraging excess algal growth.

Protection of our coral reefs is not only vital to maintaining Hanauma’s pristine beauty, but in a very real sense it is crucial to protecting the life of oceans and seas across the globe, without which, there is no life on this planet.

The 2022 United Nations Ocean Panel recognized that Citizen Science by organic community stewards like Friends of Hanauma Bay plays a vital role in identifying and mitigating threats to marine ecosystems. Click here to learn more.