An effort has been underway since 2006 to monitor long-term trends in biological and anthropogenic activities in Papahānaumokuākea using passive acoustic methods. The use of acoustic tools to record sounds in aquatic environments is important for monitoring biological activity in remote habitats. This is because many species of fish, invertebrates and marine mammals regularly produce sounds for communication, displaying and/or environmental sensing. In addition, acoustic monitoring is also an effective means of detecting human activities in a marine habitat, such as vessel traffic and explosives used in fishing. The Ecological Acoustic Recorder (EAR) is a digital, low power acoustic recording system designed to sample the ambient sound field. Preliminary findings reveal that Pearl and Hermes Atoll in the Monument, has the highest noise levels measured by an EAR deployed in the Pacific. It is possible that the increased acoustic energy may be tied to high levels of productivity in the water. At French Frigate Shoals, dolphin and fish signals were common and, somewhat surprisingly, the song of humpback whales (Megaptera novaeangliae). This was unexpected because humpback whales were not thought to occur in significant numbers in the NWHI. Since September of 2006, eight Ecological Acoustic Recorders were deployed in the Papahānaumokuākea Marine National Monument. This project is lead by Dr. Whitlow Au and Dr. Marc Lammers.
Mapping Human Impacts
The human impacts mapping project was developed to provide Papahānaumokuākea Marine National Monument managers and scientists with a framework for viewing an array of spatial data and analyses on the current impacts of anthropogenic (human) threats. Information included in the maps range from the frequency of thermal stress derived from sea surface temperatures to spatial modeling of seawater acidification. Other information includes shipping activity, increased ultraviolet radiation from global climate change, marine debris, alien species, historical bottomfishing and lobster trapping activity, and research use. All the data were combined with habitat maps to make objective and repeatable predictions about how those threats potentially impact the marine ecosystem. The results show that cumulative human impacts peak at the middle of the Archipelago. Sea temperature change was perceived as the worst threat, followed closely by sea water acidification, sea level rise, ship based pollution and bottomfishing were relatively moderate. This project is lead by Dr. Robert Toonen and Dr. Kim Selkoe.