Beyond the Blue: Palau Mapping

On September 19, 2025, NOAA Ship Okeanos Explorer set sail from Guam to begin the year’s final mapping expedition in Palauan waters. Aboard, we also had a team of guest scientists that you wouldn’t usually find on a mapping survey. These “misfits” were there to conduct an opportunistic visual survey for marine mammals. While NOAA Fisheries conducts its own dedicated marine mammal surveys, the visual observers from Whaleology (Cory Hom-Weaver and Felipe Triana) were seizing the opportunity to collect data in an understudied part of the Palau National Marine Sanctuary. But more importantly, they were also there to build capacity with Palauan ocean managers to study marine mammals.

The first dedicated visual and acoustic survey of cetaceans (which include whales, dolphins, and porpoises) in Palau was conducted in 2012 by Whales Alive and Sustainable Decisions in collaboration with the government of Palau (Andrews et al. 2019). That survey came together on a shoestring budget and relied on the sailboat M/V Endless Summer to donate both crew hours and ship time to make the effort possible. Subsequent surveys in 2013, 2019, and 2024 have built on that foundation. Together, these efforts confirmed the presence of 15 different cetacean species around Palau. This knowledge is particularly important because Palau established a national marine sanctuary in 2015, designating 80% of the nation’s exclusive economic zone (EEZ) as a fully protected, no-take marine reserve. To protect the animals within the sanctuary, we first need to understand who inhabits these waters.

On this expedition, a team of volunteers from three Palauan agencies: the Division of Maritime Security, Palau’s Land and Resource Information System Office (PALARIS), and the Palau International Coral Reef Center (PICRC), joined the science team aboard Okeanos Explorer to help collect visual data in areas of the sanctuary that had not been previously surveyed. Before boarding the vessel, Whaleology’s Olive Andrews and Cory Hom-Weaver conducted training sessions on how to record marine mammal sightings and enter the information into specialized software. Each trainee came from a very different professional background: Jeremy Nakamurka, a police officer with Palau’s Division of Maritime Security, usually spends his days patrolling Palau’s waters to guard against illegal fishing within the EEZ. Rodney Yoshida works as a geographic information system (GIS) analyst for PALARIS, where he flies drones and collects data critical for managing Palau’s land and natural resources. And Manzel Ngirmeriil currently serves as a government representative for the President of Palau. Though their backgrounds differ, all three share a deep connection to the ocean.

Felipe and Cory worked with the trainees each day to get them comfortable identifying different types of whales and dolphins based on behavior and morphological differences. They learned how to use an angle board to record the angle of a sighting relative to the ship, and reticle poles to judge the distance of that sighting. It was a 360-degree learning opportunity. Not only did our Palauan colleagues learn from us, but they also taught us about their professional and cultural ties to the ocean. Jeremy spends most days at sea, and provided some really helpful insights about where we may find fish aggregating devices or seamounts.

Just over a week into the survey, we had recorded four sightings in total. Most were pantropical spotted dolphins, but we also encountered a pod of short-finned pilot whales close to shore. Manzel, who was on watch, first spotted the dark dorsal fins breaking the surface. He radioed in: “I have a sighting!” Felipe, our data recorder, immediately asked for the details — such as the cue that led Manzel to notice the animals — before rushing over to help take photographs for species identification. Collecting all the data for a sighting often requires teamwork, as animals can disappear quickly in the swell. That day’s collaboration and excitement perfectly captured the spirit of this endeavor.

It was inspiring to work with local Palauan partners. Manzel, Jeremy, and Rodney all care deeply about their country’s ocean resources, and now they have the tools and training to teach others or even lead future marine mammal surveys themselves. Science is strongest when it is shared and locally owned. Passing the binoculars ensures that knowledge doesn’t just stay with us, it stays with Palau.

By Cory Hom-Weaver