In the first such effort in this location, we mapped the waters surrounding Palmyra Atoll to help researchers develop reef fish management strategies, optimize biological monitoring sampling design, and evaluate natural and man-made changes over time (e.g., climate change, invasive species eradication, and lagoon causeway mitigation).
Why We Care
Like tropical rain forests, coral reefs are among the oldest ecosystems on Earth, providing us superabundant economic, environmental, biological, and cultural endowments. While coral reef ecosystems are deteriorating globally at an alarming rate, the Palmyra Atoll harbors a vibrant and diverse coral reef ecosystem encompassing over 130 species of stony corals and many top predators, such as sharks. Detailed habitat descriptions provided by maps are important benchmarks for research under way at Palmyra Atoll aimed at understanding global warming, disappearing coral reefs, and invasive species and working to sustain coral reef ecosystems.
What We Did
We identified the extent, type, and condition of benthic habitats that comprise the shallow-water (30 meters or less) coral reef ecosystem in the northern Pacific Palmyra Atoll, located roughly halfway between Hawaii and American Samoa. Sea floor habitat maps were completed for a 50-square-kilometer area using high-resolution satellite imagery. We also mapped the distribution of Rhodactis howesii, a type of mushroom coral, flourishing near the wreckage of a sunken long line vessel.
What We Found
The reefs around this atoll are some of the most pristine anywhere in the world, and studying them provided a standard against which the health and function of coral reefs elsewhere can be assessed. Of the ecosystem area we mapped, 85.75 percent was coral reef and hard bottom, and 14.25 percent was unconsolidated sediment, a ratio higher than any other reef mapped in United States jurisdiction. The R. howesii coral was rare or absent in other parts of the Palmyra coral reef ecosystem, suggesting that it may be an invasive species in this area. The results were presented to The Nature Conservancy and the Palmyra Atoll Research Consortium.