Scientists Explore Deep Reef Complex in the Hawaiian Islands

July 24, 2009

During a seven-day research cruise in the Au'au Channel between the Hawaiian Islands of Maui and Lanai, NOAA scientists and their partners are surveying a large mesophotic reef complex to better understand the biodiversity, ecology, and function of deep reef ecosystems.

Hermatypic (reef-forming) coral covering a large part of the substrate at 75–85 m depths off Maui, 
    Hawaiian Islands.
Hermatypic (reef-forming) coral covering a large part of the substrate at 75–85 m depths off Maui, Hawaiian Islands.

The deep reef complex was detected a couple of years ago by staff of the Department of Land and Natural Resources, State of Hawaii, during surveys using a remote camera to look for black coral. Found between depths of 75–85 m, these corals constitute some of the deepest hermatypic reefs in the nation.

The expedition is being conducted by a team of scientists on the NOAA Ship Hi'ialakai and is led by Dr. Frank Parrish of the NOAA Pacific Islands Fisheries Science Center. The scientific party includes NOAA researchers and colleagues from the State of Hawaii and the University of Hawaii Joint Institute for Marine and Atmospheric Research. It is part of a broad-ranging but tightly integrated series of investigations of the Au'au Channel planned for 2008 to 2010. The project leverages the diverse and extensive experience of state, federal, and university scientists in Hawaii and employs the range of research tools available in the state. Most recently, in spring of 2009, the NOAA submersible Pisces IV, operated by the Hawaii Undersea Research Laboratory at the University of Hawaii, was used to explore the deep reef site and collect biological specimens for research.

Plate coral and macroalgal community at 78 m depth offshore off west Maui, as viewed from the 
    submersible Pisces IV.
Plate coral and macroalgal community at 78 m depth offshore off west Maui, as viewed from the submersible Pisces IV.

During the current cruise, the Hi'ialakai will conduct systematic surveys of the seafloor and its inhabitants using towed remote cameras and support Scuba-diving scientists who will investigate the coral beds and characterize the habitat and assemblage of fishes. Arrays of oceanographic instruments placed at the study site a year ago will be recovered, data stored in them will be downloaded, and the arrays will be redeployed. The deep coral ecosystem research is part of a 3-year regional multi-agency project supported by the NOAA National Center for Coastal and Ocean Science.