Fish and turtles are great, but will I see a coral reef?
Visitors are often led to believe that they will snorkel on a living coral reef at Hanauma, but the reef they see is mostly barren and brown. Then they read, or are told, that the coral was killed by human trampling. Although untrue, this explanation appears in many books, visitor guides, and websites.

What is the true story of Hanauma's reef? Actually, all is as it should be. The reef off the beach is mostly a fossil reef—the remains of coral that grew thousands of years ago when sea level was higher. The top of the reef is now too shallow and exposed to support much coral growth. It consists of smooth, barren-looking limestone rock that is entirely natural, and was deposited over the old coral reef by tiny plants called coralline algae. Most folks have never heard of coralline algae, but they are an essential and sometimes even primary builder of tropical reefs, especially in Hawai`i.

Living coral is plentiful in the deeper areas of Hanauma, but these areas are often too rough for safe and enjoyable snorkeling. However, 13 species of living coral can be seen along the sides of the lagoons in the shallow snorkeling areas inside the reef. My book illustrates them all, and tells you how to identify them.

Although only about 1 percent of the reef top is living coral, the coralline algae is alive too. Visitors are requested not to walk on top of the reef.

Hanauma Bay's inner reef