CRED Completes 2008 RAMP Cruises in the Hawaiian Archipelago

Staff of the PIFSC Coral Reef Ecosystem Division Coral Reef (CRED) led research cruises to complete Reef Assessment and Monitoring Program (RAMP) surveys in the Hawaiian Archipelago for 2008. The expeditions were part of NOAA's long-term strategy to describe coral reef habitats and biota in the Pacific Islands Region and measure changes in coral reef ecosystems caused by natural processes and human activities. The research is part of NOAA's broader Coral Reef Conservation Program.

The 2008 RAMP survey of the Northwestern Hawaiian Islands (NWHI) was carried out from September 11 to October 12 under the leadership of Peter Vroom, a CRED scientist employed by the University of Hawaii Joint Institute for Marine and Atmospheric Research (JIMAR). The 32-day cruise aboard the NOAA Ship Hi'ialakai conducted monitoring operations at French Frigate Shoals, Maro Reef, Laysan Island, Lisianski Island/Neva Shoals, Pearl and Hermes Atoll, Kure Atoll, and Midway Atoll.

During fish surveys in the Northwestern Hawaiian Islands, PIFSC scientists often encounter large specimens of ulua, an important apex predator in coral reef ecosystems of the Hawaiian Archipelago.

The research crew completed 109 towed-diver surveys covering 250 linear km of reef habitat and measured fish abundance at 148 Rapid Ecological Assessment (REA) survey sites and 60 benthic REA sites. They also collected data from numerous oceanographic instruments previously installed on the seafloor and deployed other instruments. One of the notable findings of the NWHI survey was the observation of large blooms of the green alga Boodlea composita in all habitat types at Kure Atoll and along the northeastern backreef of Midway Atoll.

Although the alga covered up to 100% of the seafloor in certain areas, the majority of substrates affected were of mixed sand and rubble composition with low percent cover of live coral. Another notable, and unexpected, result was that only 41 sharks were recorded during towed-diver surveys in 2008, down significantly from the 211 shark sightings recorded in 2006. Limited coral bleaching and paling were observed at many islands, although it is uncertain if this represents a normal summertime population phenomenon or if the bleaching was higher than typical levels.

The 2008 RAMP cruise to the main Hawaiian Islands (MHI) was conducted during October 16-November 14 by the NOAA Ship Oscar Elton Sette under the direction of JIMAR scientist Bernardo Vargas-Ángel. The field party included scientists from CRED, Hawaii Division of Aquatic Resources (DAR), University of Hawaii, San Diego State University, and National Geographic. During the 30-day expedition, the scientists completed integrated ecosystem assessments of fish, corals, macroinvertebrates, and algae on reefs of the islands of Hawaii, Maui, Lanai, Molokai, Oahu, Kauai, and Niihau, and around Lehua Rock. They also conducted oceanographic sampling and water quality assessments of the surrounding waters. The cruise primarily focused on reef areas not monitored by DAR.

For the first time on a RAMP cruise in the MHI, the microbial community was surveyed. In addition, a National Geographic DropCam (underwater camera) system was tested and 36 Autonomous Reef Monitoring Structures (ARMS) were deployed on the seafloor to monitor biodiversity of cryptic invertebrates. In addition, water samples were collected to assess carbonate chemistry associated with ocean acidification, a key threat of global climate change.

Consistent with previous observations during RAMP surveys to the MHI, the observed abundance of apex predators, such as sharks and jacks, was low. The prevalence of coral disease was also low, and there were signs of coral community deterioration on reefs near some populated areas.

For more information contact: Rusty Brainard