Alien invasive species are introduced species that have arrived accidentally by ballast water or hull-fouling of ocean-going ships, or by accidental and intentional releases of aquaculture species, aquarium specimens or bait.  The most harmful of these invaders displace native species, change natural reef structures and food webs.   Though there are hundreds of introduced algae and invertebrate species in Hawai‘i, only a few have demonstrated exceptionally dangerous invasive tendencies.  Below are some of the most destructive alien algae blooms found on our local reefs. Early detection of these species are crucial to reef health.

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