Beyond the Blue: Palau Mapping

Beyond the Blue: Palau Mapping 1 (EX2505)

The first expedition of the series focused on the area around the southwest islands that make up the states of Sonsoroal and Hatohobie. During the mapping survey, multibeam sonar revealed a remarkable discovery: a previously uncharted shallow seamount rising to less than 100 meters (~328 feet) below the surface. Satellite-derived bathymetry had suggested significantly greater depths, but the ship’s sonar showed the feature to be several hundred meters shallower than expected. Seamounts of this depth are rare and often serve as hotspots for marine life, supporting rich fish communities and commercially important species. Its presence within the PNMS adds significantly to the known habitat diversity of Palau’s deep waters.

In addition to scientific operations, this expedition also saw the deployment of the student-built miniboat Yaquina Neversink, contributing to Educational Passages’ global program connecting young people with ocean science through autonomous drifting vessels. The deployment enabled the continuation of the boat’s trans-Pacific journey and offered an inspiring touchpoint between Palauan students and their peers abroad.

A major emphasis of this first expedition was building local technical capacity in deep-sea exploration. Five junior regional advisors (JRAs) from PICRC participated in a training program that entailed five weeks onshore and three weeks at sea, and was designed to introduce participants to deep-sea science. Before sailing, the JRAs completed training sessions in Koror, Palau, shadowing PICRC researchers, learning eDNA processing techniques, supporting aquarium operations, and launching independent research projects. They also participated in webinars with NOAA experts to understand the broader context of ocean exploration.

Once aboard Okeanos Explorer, the JRAs worked alongside NOAA scientists to collect eDNA samples, operate oceanographic instruments, and assist with seafloor mapping. Their work not only strengthened the scientific goals of the mission, but will also contribute to Palau’s long-term capacity to manage and study deep-sea ecosystems. At the end of the program, the JRAs wrote technical reports, developed educational materials, and presented their research findings, helping to expand the reach of their training and support future community engagement around deep-sea exploration.

Beyond the Blue: Palau Mapping 2 (EX2506)

The second expedition of the series continued to the north and east of Babeldaob, targeting regions where bathymetric data were scarce, particularly along the Palau Trench and the Kyushu-Palau Ridge.

During this expedition, the multibeam sonar system revealed the structure of a previously unmapped seamount. Satellite-derived data suggested the feature rose to within 250 meters (820 feet) of the surface, while new sonar data refined this estimate to 243 meters (797 feet) — remarkably close to earlier predictions. From its base at roughly 4,400 meters (14,435 feet) depth, the undersea mountain stands about 4,200 meters (13,780 feet) tall, making it comparable in height to Colorado’s famed Pikes Peak.

In addition to mapping and eDNA sampling, the mission team also undertook a full calibration of the EK80 midwater sonar systems. Though time-consuming, this process is crucial for ensuring the highest possible quality for fisheries and ecosystem-level acoustic data.

Beyond the Blue: Palau Mapping 3 (EX2507)

The final expedition of the Beyond the Blue: Palau Mapping series took place September 19-October 3. During this expedition, the mapping team surveyed at least ten seamounts — possibly more, pending post-processing to confirm which features have at least 1,000 meters (~3,281 feet) of relief. The team focused heavily on mapping the southwest quadrant of the PNMS, just south of Palau’s domestic fishing zone. This region was identified by PICRC as a high-priority area due to its ecological importance and lack of deep-sea data.

This final expedition was unique in that it included a dedicated marine mammal observation team from Whaleology. While Okeanos Explorer is not a marine mammal survey vessel, the expedition provided the opportunity for visual observers to collect sightings data in some of the least-surveyed waters of the PNMS. Their work was paired with an extensive training program for Palauan participants: representatives from the Division of Maritime Security, the Office of Palau Automated Land and Resources Information System (PALARIS), and PICRC joined the mission team to learn how to record marine mammal sightings, enter data into specialized software, and identify cetaceans at sea. Each Palauan observer brought distinct experience — from maritime law enforcement to GIS analysis to governmental service — but all shared a deep connection to the ocean and a commitment to safeguarding Palau’s natural heritage.

Engagement and education remained central to the mission. During the expedition, the crew conducted a live ship-to-shore interaction with eighth-grade students visiting PICRC. The students were studying marine mammals and were thrilled to speak directly with the marine mammal survey team aboard Okeanos Explorer, gaining real-time insights into deep-sea fieldwork and ocean stewardship.

Members of the expedition team filter water samples for environmental DNA (eDNA). Image courtesy of NOAA Ocean Exploration, 2025 Beyond the Blue: Palau Mapping. Download largest version (jpg, 1.38 MB)

A Foundation for the Future

Together, these three expeditions dramatically expanded high-resolution mapping coverage of Palau’s deep waters and laid critical groundwork for future exploration and management of the PNMS. The discovery of new seamounts, refined bathymetric models, and extensive eDNA sampling will help scientists better understand biodiversity, habitat distribution, and deep-sea geological features.

Equally important, the expeditions strengthened Palau’s scientific capacity through workforce development, mentorship, and hands-on experience for emerging Palauan ocean professionals.

As the data are processed and shared with Palau, they will inform science-based decisionmaking, support sustainable management of marine resources, and deepen understanding of one of the most diverse and culturally significant marine regions on the planet.