Monitoring of long-term anthropogenic and biological activities in marine habitats is a challenging task, especially at remote locations. Analysis of ambient sound can provide better understandings of marine life behavior, as well as evidence of anthropogenic activity in the remote areas. Ecological Acoustic Recorders (EARs) are instruments used to capture sounds in marine ecosystems. EARs record sound on a programmed schedule and possess a feature allowing them to record sounds triggered by the detection of high amplitude acoustic events, such as engine noise from vessels or fish scrapes on coral. An EAR was deployed at Rapture Reef in French Frigate Shoals within the Papahanaumoukuakea National Marine Monument (PNMN), a marine sanctuary that encompasses 139,797 square miles surrounding the Northwestern Hawaiian Islands.
Data collected from the instruments will help determine the frequency of anthropogenic activities and monitor biological acoustic trends at the site. For this project, data from June 2009 to May 2010 will be analyzed with the program CoolEdit. A timeline will be created to compare the events that triggered detections between years 2006 to 2010. Findings will be useful in providing managers baseline data on loud sound producing marine organisms and possible vessel presence at the sanctuary. We will compare the acoustic evidence of triggered vessel recordings with the dates of scheduled research vessels at the site, gauging the effectiveness of the marine protected area in curtailing boat traffic.
Results/Conclusions
Previous analysis of the thirteen-month period between 2006 and 2007 that an EAR was deployed at Rapture Reef, showed the event detector was triggered mostly by biological sounds produced by whales, dolphins, and fish. During this period, the detector also recorded vessel sounds. The dates of the vessel detection coincide with when the research vessel Hi’ialakai was conducting the NOAA Reef Assessment Monitoring Program scientific cruise. The lack of vessel detections during the rest of the deployment suggests this site is not typically visited by vessels other than those conducting research. Based on the analysis of data collected between 2006 -2007, we can assume that dominant sounds will be of biological origin, primarily whale vocalizations during the winter months, and fish signals. Comparing the data from 2006-2007, 2008-2009 and 2009-2010 will provide a better understanding of biological trends of these marine organisms and present possibilities for further research in taking the necessary steps to protect and preserve remote marine habitats for future generations to learn from and enjoy.