Summary

Description

Palmyra Atoll National Wildlife Refuge is the second largest atoll under U.S. jurisdiction in the Pacific Ocean. Until recently, little was known about benthic communities and, more specifically, algal abundance at Palmyra aside from species lists generated during 1916, 1955 and 1959 expeditions. Since 2000, NOAAs Pacific Islands Fisheries Science Center, Coral Reef Ecosystem Division has conducted six rapid ecological assessment surveys to monitor and gather baseline data for reefs surrounding Palmyra. Additionally, Scripps Institute of Oceanography documented benthic community structure on Palmyras reefs during a 2005 expedition. This study reports on the current state of knowledge for benthic community composition and algal community structure across the atoll. Benthic communities in fore reef areas 10 m depth were dominated by reef builders coral and crustose coralline algae covering 50 of the benthos, while turf algae, macroalgae, soft corals, and other invertebrates covered the remaining surfaces. Species of Halimeda, Lobophora, Dictyosphaeria, Galaxaura and Dichotomaria were among the 5 most common macroalgae recorded. Overall, the reef communities around Palmyra appear relatively healthy. Developing comprehensive species lists and continuing benthic monitoring will allow reef managers to detect ecosystem changes, including possible introduced and invasive species.