Kahng and Grigg 2005

scientific article | Coral Reefs

Impact of an alien octocoral, Carijoa riisei, on black corals in Hawaii

Kahng SE, Grigg RW


In 2001 Carijoa riisei, an octocoral native to the tropical Western Atlantic, was discovered overgrowing black corals in the Au’au Channel in Hawaii. In this paper data from a 2001 survey are reanalyzed and combined with new data from 2003 and 2004 to assess the ecological impact in greater detail. C. riisei differentially affected reproductively mature black coral colonies with maximum impact between 80 and 105 m. The pattern of C. riisei over growth on black corals and C. riisei on the substrata appears to be bounded by high irradiance in shallow water and cold temperature in deep water. Evidence suggests that the C. riisei settlement on black corals is facilitated by other epifauna. Once established, C. riisei spreads vegetatively and smothers the coral. The success of the C. riisei invasion appears to be unaided by anthropogenic disturbance and is at least partially attributable to Hawaii’s depauperate shallow-water (<100 m) octocoral fauna.

Research sites
Depth range
30- 115 m

Mesophotic “mentions”
0 x (total of 3844 words)

* Presents original data
* Focused on 'mesophotic' depth range
* Focused on 'mesophotic coral ecosystem'


Octocorallia (Soft Corals)
Antipatharia (Black Corals)

USA - Hawaii

Remotely Operated Vehicle (ROV)
Manned Submersible

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