Passive acoustic monitoring of marine ecosystems in the Pacific Islands Region.

Monitoring the changing state of marine habitats is a challenging task that is exacerbated when the habitats in question are in remote locations. Passive acoustic monitoring is sometimes the best, if not the only, means of gauging levels of biological and anthropogenic activities in such areas. Since 2006, the Pacific Islands Fisheries Science Center, in partnership with the University of Hawaii, has been building a network of long-term acoustic monitoring stations across the Pacific Islands Region using Ecological Acoustic Recorders (EARs). The network is currently composed of 29 long-term monitoring stations and spans the Hawaiian Archipelago, American Samoa, the Line Islands, Johnston Atoll, Wake Atoll, Guam, and the Commonwealth of the Northern Mariana Islands. EARs are diver-deployed and refurbished by local partners and/or during annual or biennial research cruises to deployment locations. A wide range of natural and anthropogenic acoustic signals are monitored, including sounds produced by invertebrates, fish, cetaceans, vessels, and surface weather events. The long-term trends in biological acoustic activity obtained through this network will be used to gauge the relative stability of the ecosystems associated with each location. Detections of vessels are common at many locations and provide a quantitative means of establishing levels of anthropogenic activity.