The snowflake coral, Carijoa riisei, is a damaging invasive species found in the ocean waters of Hawaii. This marine invasive out-competes and overgrows native coral species, possibly threatening the precious black corals found in deeper waters off Maui.

A filter-feeder, the snowflake coral has spread to all the main Hawaiian Islands, gorging itself on the tiny larvae of crustaceans and shellfish swirling in waves and currents. Unlike other corals it does not need sunlight; it grows in thick aggregations in the shadows of pier pilings and ledges, as well as rocky surfaces, artificial reefs and coral beds far below the water's surface.

First discovered in 1972 at Pearl Harbor, the snowflake coral may have been transported to Hawaii as hull fouling or as larvae in ships' ballast water. Scientists believe it came from the Indo-Pacific ocean.

The Aquatic Invasive Species team, DLNR's Division of Aquatic Resources, is attempting to eradicate snowflake coral infestations around Kauai. Efforts to eradicate this invasive species in Port Allen have yielded some valuable lessons as researchers continue to survey and treat infestations. Surveys on Niihau did not detect snowflake coral.