Comprehensive Scientific Monitoring Underway on Coral Reefs of the Mariana Archipelago

April 5, 2009
NOAA Ship Hi'ialakai in 2007 at Farallon de Pajaros (Uracas), the northernmost island in the Mariana 
    archipelago and now part of the new Marianas Trench Marine National Monument. NOAA photo by R. Schroeder.
NOAA Ship Hi'ialakai in 2007 at Farallon de Pajaros (Uracas), the northernmost island in the Mariana archipelago and now part of the new Marianas Trench Marine National Monument. NOAA photo by R. Schroeder.

On April 5, 2009, scientists from the Coral Reef Ecosystem Division (CRED) of the NOAA Pacific Islands Fisheries Science Center (PIFSC), along with visiting scientists from the NOAA Fisheries Pacific Islands Regional Office, the University of Guam, and San Diego State University, began a 30-day expedition around Guam and most of the islands of the Commonwealth of the Northern Mariana Islands (CNMI) aboard the NOAA Ship Hi'ialakai. Sponsored by NOAA's Coral Reef Conservation Program, this cruise is the fourth biennial Mariana Archipelago Reef Assessment and Monitoring Program (MARAMP) conducted by CRED. The strategic goals of this research are to improve scientific understanding of coral reef ecosystems throughout the Pacific and serve as the basis for improved conservation and resource management. The recent presidential designation of the Marianas Trench Marine National Monument in the northern part of this archipelago highlights the importance of this research.

Islands of the Mariana Archipelago that will be surveyed April-May 2009 and the proposed 
        MARAMP cruise track for the NOAA Ship Hi'ialakai.
Islands of the Mariana Archipelago that will be surveyed April-May 2009 and the proposed MARAMP cruise track for the NOAA Ship Hi'ialakai. Click here or the image above for higher resolution version.

The Mariana Archipelago is a chain of 15 volcanic islands, many surrounded by nearly pristine and rarely surveyed coral reef ecosystems. The southern islands consist of old, elevated limestone, while the remote, largely uninhabited northern islands are young, volcanic islands with steep seaward slopes. Several of the volcanic islands are still very active and have produced major eruptions in the past few years or decades. The impressive coral reef ecosystems surrounding these islands support a wealth of marine biota and a biological diversity among the highest in the U.S. Pacific region. The waters around the northern islands also support a high biomass of reef predators, including numerous sharks. These reef ecosystems provide a valuable natural laboratory for scientific studies essential for improving resource management and reef conservation.

The first leg of the MARAMP 2009 cruise (HI-09-02, April 5-14) will visit the islands of Guam, Rota, Aguijan, Tinian, and Saipan. The second leg (HI009-03, April 18-May 7) will visit Saipan, Sarigan, Pagan, Asuncion, Supply Reef, Farallon de Pajaros (Uracas), Maug, Agrihan, Alamagan, Guguan, Zealandia Bank, and Anatahan. Dr. Robert Schroeder, a CRED scientist employed by the NOAA-University of Hawaii Joint Institute for Marine and Atmospheric Research (JIMAR), will serve as Chief Scientist on both cruise legs.

The Shepard's angelfish (Centropyge shepardi) at Pagan. NOAA photo by R. Schroeder.
The Shepard's angelfish (Centropyge shepardi) at Pagan. NOAA photo by R. Schroeder.

As in previous MARAMP cruises in 2003, 2005, and 2007, this year's cruise will employ a suite of standardized, multidisciplinary methods used on other RAMP cruises throughout the Pacific. These methods include Rapid Ecological Assessments (REA) for fish, corals, other large invertebrates, and algae; towed-diver surveys for large fish and habitat composition; and oceanographic studies. The oceanographic research includes the measurement of conductivity, temperature, and density of the water column (CTD casts); water sampling for measuring levels of chlorophyll-a and nutrients such as nitrogen, phosphate, and silicate; and deployment of sea-surface temperature recorders, subsurface temperature recorders, and acoustic Doppler current profilers (ADCP). Scientists will also deploy ecological acoustic recorders (EARs) on the seafloor to learn about changes in the presence and activity of fish, marine mammals, crustaceans, and other sound-producing marine life, even when researchers are not there to record them. Autonomous reef monitoring structures (ARMS)—small standardized collecting devices that help assess the biodiversity of small cryptic invertebrates—will also be deployed as part of the Census of Coral Reef Ecosystems (CReefs) project.

After completing this coral reef monitoring cruise, the Hi'ialakai will stop briefly in Saipan, then transit directly to her home port at Pearl Harbor in Honolulu. During the return voyage, the ship's scientific crew will use passive sonar to conduct acoustic surveys of cetaceans.