Palmyra Atoll is a National Wildlife Refuge 1,000 miles south of the Hawaiian Islands. It is administered by the U.S. Fish and Wildlife Service, with part of the atoll owned by The Nature Conservancy. It is a small atoll of 680 acres but its 480,000 acres of lagoons, coral reefs and submerged lands in the middle of the Pacific Ocean with everything from whales and dolphins, sharks, tuna, sailfish, sea turtles, manta rays, and giant clams to thousands of exotic fish and corals give an ideal platform to learn in an almost pristine environment about a natural ecosystem.

        Palmyra offers the opportunity for scientific studies aimed at protecting both Palmyra and other island ecosystems in the Pacific and around the world. We have used acoustic monitoring to study odontocete presence at Palmyra Atoll. A High-frequency Autonomous Recording Package (HARP) has been deployed which samples at 200 kHz with a duty cycle of ¼. This instrument has recorded since October 2006 at the atoll. Visual and acoustic surveys were conducted around Palmyra Atoll using a four-element towed hydrophone array sampling real-time at 200 kHz and during the last survey with one channel at 480 kHz to obtain species-specific acoustic data. These data are used as reference for automatic detection algorithms applied on the long-term recordings. To date, acoustically and visually detected odontocetes include bottlenose dolphins (Tursiops truncatus), spinner dolphins (Stenella longirostris), melon-headed whales (Peponocephala electra) and beaked whales of the genus Mesoplodon. The long-term HARP data reveal acoustic activity primarily at night time and predominantly odontocete clicks. Both the beaked as well as the melon-headed whales are present year round and show a distinct daily acoustic activity cycle.

Objectives:

1. Gather acoustic data while in the presence of the different species to describe the acoustic repertoire of known species and find parameters that discriminate between them. With this information we are developing algorithms to automatically look through the long-term data and classify calls to species level.
2. Use the call counts and analyze dial or yearly patterns and correlate abundance with ecological or oceanographic factors.
3. Gain insights into the natural behavior of animals in a natural ecosystem as a reference to judge impact of human influences on their behavior at other sites.