Research Survey Targets Deep Reef Ecosystem in the Au'au Channel of the Main Hawaiian Islands

August 1, 2008
An example of extensive cover by hermatypic corals at depths of 75-85 m on a reef off Maui (Photo by 
    A. Montgomery)
An example of extensive cover by hermatypic corals at depths of 75-85 m on a reef off Maui (Photo by A. Montgomery)

A seven-day cruise of the NOAA Ship Oscar Elton Sette is underway to survey a large reef complex in waters of the Au'au Channel between the Hawaiian islands of Maui and Lanai. The reef complex was detected in 2006 by staff of the Department of Land and Natural Resources, State of Hawaii, during remote camera surveys looking for black coral. Located at depths of 76-85 m, the Au'au Channel reefs represent some of the deepest habitats of hermatypic (reef-building) corals in the nation and present an opportunity to better understand the biodiversity, ecology and function of deep reef ecosystems.

The Sette expedition is being conducted by research staff of the NOAA Pacific Islands Fisheries Science Center as 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 marine scientists in Hawaii and employs the wide range of research tools available in the State.

Plate coral and macroalgae at 78 m on a reef offshore of west Maui. (Photos taken from the 
    submersible Pisces IV, HURL)
Plate coral and macroalgae at 78 m on a reef offshore of west Maui. (Photos taken from the submersible Pisces IV, HURL)

Most recently, in spring of 2008, the submersible Pisces IV, operated by the Hawaii Undersea Research Laboratory, University of Hawaii, was used to explore the Au'au Channel site and collect "voucher" specimens of marine life to help verify the kinds of animals and plants inhabiting the reef.

Chief Scientist for the Sette cruise is Frank Parrish of the Center's Ecosystem and Oceanography Division. The scientific team will conduct systematic surveys using remote cameras and hydro-acoustic instruments (sonar) to characterize the deep coral reef habitat and the "scattering layer" of organisms living in the water column above the reef. Anchored arrays of oceanographic instruments will also be deployed. These devices will be left in place for a year to measure temperature of the seawater and various characteristics of the ocean current. They will be recovered on a research cruise planned for 2009.