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There are 66 confirmed species of Scleractinian corals recorded at normal
diving depths in Hawai'i to date. It can be difficult to identify some species with certainty, especially
underwater, without examining the skeletal structure of the calices (cups inhabited by
individual polyps). Hawai'i's isolated location and subtropical water temperatures
have led to the formation of several endemic species, variations within single species, and
intergradations among others. Most corals are colonies of thousands of polyps
(clones) which form the familiar "coral head". The exceptions are the Oval
Cup and Mushroom Corals, which are generally single animals. Corals receive their
distinctive colors from algae cells called zooxanthellae embedded within the animals'
transparent flesh. Oxygen and carbohydrates that zooxanthellae produce by
photosynthesis are the principal source of energy for most corals, with zooplankton having
little or no importance. Cup Corals are an exception; lacking zooxanthellae, they
feed upon large zooplankton at night. Many species can be readily identified by
color, but there are always exceptions. Have a look at the photos for some common
variations.
Corals may grow as little as 1/4 inch per year and are
prone to damage by anchors, swimmers, and divers. Please take care to avoid touching
living corals; their delicate flesh may be injured if pressed (even lightly) against the
razor-sharp skeleton, allowing infection or algae to take hold and potentially kill the
entire colony. I t is illegal to collect live corals or "live rock" at any
time without a permit in Hawai'i. |
