The Palau International Coral Reef Center (PICRC) has released a new report titled “Preliminary assessment of fish composition at a Fish Aggregating Device in Palau using a mid-water baited remote underwater video station.” The study provides the first insights into fish communities gathering around a Fish Aggregating Device (FAD) in Ngarchelong State.
FADs are floating structures designed to attract fish—particularly pelagic species—making them more accessible to local fishers. While FADs are valuable tools for sustainable fisheries, their ecological impacts are still being studied. PICRC’s research aimed to better understand how fish species interact with these devices under different moon phases during the summer months of 2024.
To collect this data, researchers deployed a Baited Remote Underwater Video Station (BRUVS) — a non-invasive underwater camera system equipped with bait to attract nearby fish. The BRUVS allows scientists to observe species diversity, abundance, and behavior in mid-water habitats without disturbing the environment.
During the survey, 17 species of fish were recorded around the FAD. The highest abundance of fish occurred during the full moon, while the first quarter moon saw the greatest biomass. The three most common species observed were rainbow runners, bigeye trevally, and mackerel scads. Interestingly, all individuals recorded were smaller than their size of maturity, suggesting that FADs may serve as important aggregation points for younger fish. The team also documented a significant presence of silky sharks, a pelagic species known for its graceful swimming and ecological importance.
“Understanding how FADs influence pelagic ecosystems is crucial for both fisheries management and marine conservation,” said Dr. Piera Biondi, PICRC researcher and lead author of the report. “Our preliminary results highlight the need for continued monitoring, especially across different moon phases and seasons, to better understand how these devices shape fish behavior and populations in Palau’s waters.”
Future surveys, building on this preliminary dataset, will strengthen understanding of how lunar cycles and seasonality affect fish assemblages around FADs. This research supports Palau’s ongoing efforts to balance sustainable fishing practices with marine biodiversity conservation.
For more information or to access the full report, please visit www.picrc.org.