American Samoa & the Pacific Remote Islands: Ofu & Olosega Islands

About the Expedition

On January 21, 2010, scientists from the Coral Reef Ecosystem Division of the NOAA Pacific Islands Fisheries Science Center (CRED/PIFSC), along with visiting scientists from the Hawaii Division of Aquatic Resources, Scripps Institution of Oceanography, San Diego State University, the US Fish and Wildlife Service, and local agencies in American Samoa, departed on a three month expedition to Johnston Atoll, Howland and Baker Islands, American Samoa, Jarvis Island, Palmyra Atoll, and Kingman Reef aboard the NOAA Ship Hi'ialakai. This is the fifth biennial Pacific Reef Assessment and Monitoring Program (Pacific RAMP) expedition to American Samoa and the seventh to the Pacific Remote Island Areas. The expedition is sponsored by NOAA's Coral Reef Conservation Program (CRCP) and is divided into three segment sequentially led by Chief Scientists Benjamin Richards, Rusty Brainard and Jamison Gove.

The strategic goal of this research is to improve scientific understanding of coral reef ecosystems throughout the Pacific, and serve as the basis for improved conservation and resource management. The recent designation of the Pacific Remote Islands Marine National Monument highlights the importance of this research.

With their extremely isolated location, many of the Pacific Remote Island Areas host a vibrate marine ecosystem. Previous Pacific RAMP cruises have documented relatively high coral cover and diversity; and high densities of large-bodied reef fish including large numbers of apex predators such as Grey Reef Sharks (Carcharhinus amblyrhynchos) and Scalloped Hammerhead sharks (Sphyraena lewini). Many of these apex predators are rare near human population centers. AS in previous years, this Pacific RAMP cruise will perform a suite of standardized multi-disciplinary methods which include Rapid Ecological Assessments (REA) for fish, corals, other large invertebrates, and algae; towed-diver surveys for large-bodied fish and habitat composition; and oceanographic studies, which include the measurement of conductivity, temperature, and density of the water column (CTD casts); water sampling; and deployment of sea-surface temperature (SST), subsurface temperature recorders (STR) and acoustic doppler current profilers (ADCP). Scientists will also be deploying Ecological Acoustic Recorders (EARs) to learn about changes in the presence and activity of marine mammals, fish, crustaceans and other sound-producing marine life when researchers aren't there to record it otherwise. Autonomous reef monitoring structures (ARMS) will also be deployed as part of the CReefs project. ARMS are simple, standardized collecting structures designed to roughly mimic the structural complexity of reef habitats. They allow for the identification of small, hard-to-sample, but ecologically important cryptic invertebrates. ARMS are being utilized throughout the Pacific and globally to systematically assess spatial patterns and temporal changes of biodiversity. Use of the EARS and ARMS are an exciting addition to RAMP data collection efforts.

Follow along below to learn more about where we are going, what we are seeing, and what we have found ...

Thursday, March 11, 2010

Ofu & Olosega Islands

View of the south side of Ofu (left) and Olosega (right)
(Photograph by Kerry Grimshaw)

By Kerry Grimshaw

We are currently working near the islands of Ofu and Olosega, which are part of the Manu’a group of islands (which also includes Ta'u). They lie approximately 100 km northeast of Tutuila. Although geographically separate, these islands are often referred to together because they are only separated by a narrow straight (approximately 75 m) that is bridged by a shallow coral reef. The twin islands of Ofu (on the west), and Olosega (on the east) are formed by two sharply eroded, overlapping shield volcanoes which gives these islands a dramatic landscape.

Ofu and Olosega are inhabited with the majority of their population (approximately 500 people according to the 2000 census figures) living in the 2 main villages of Ofu and Olosega. An interesting fact I learned from the National Park of American Samoa’s website is that the To’aga archeological site near Ofu Beach has evidence of more than 3,000 years of continuous human occupancy and some modern descendants still live nearby in Ofu Village.

The south-coast beach of Ofu-Olosega with it’s the 4km (2.5mi) stretch of white sand is one of the most beautiful in the South Pacific. Much of the southern coast is also part of the National Park of American Samoa. Along this stretch there are excellent opportunities to snorkel and see some of the 300 species of fish and 150 species of coral that can be found there. Through our shallow water multibeam mapping in 2004 we learned that Ofu and Olosega had a previously uncharted bank top that is less than 300m deep and extends between 0.2 – 2km offshore before dropping to abyssal depths.

Our work this year will continue efforts to monitor fish, coral, algal, invertebrate, and microbial communities at depths ranging from 3 - 30m (10 - 100 feet) deep, as well as a suite of oceanographic observations to better understand the processes influencing these organisms. This data will be compared with that from the other islands we've visited to get an understanding of overall reef health of this area of the world.

1 comment:

Frank MMarch 12, 2010 at 8:25 AM
I have been following your voyage and just was informed of your blog reporting daily activities. It is fascinating and educational. I understand that there are SanDiego people on board, they may not know it but there is a JETS fan on board also. hope they are getting along. Frank M
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