Corallimorph Invasion Palmyra: Data

In 2007, a phase shift from corals to corallimorpharians (CM) was documented at Palmyra Atoll, Line Islands, centered around a shipwreck. Subsequent surveys revealed CM to be overgrowing the reef benthos, including corals and coralline algae, potentially placing coral ecosystems in the atoll at risk. This prompted the U.S. Fish and Wildlife Service, the lead management agency of the atoll, to remove the shipwreck. Subsequent surveys showed reversal of spread of CM around the ship impact site. We explain patterns of spread of the CM in terms of life history and local currents and show with a pilot study that pulverized bleach may be an effective tool to eradicate CM on a local scale. If applied strategically, particularly in heavily infested (>66% cover) areas, active intervention such as this could be an effective management tool to reduce CM impact on localized areas and decrease colonization rate of remaining reefs. This is the first documentation of the response of an invasive cnidarian to shipwreck removal. While this was a singular event in Palmyra, the spatial and temporal patterns of this invasion, as well as the eradications lessons described herein, are useful for anticipating and controlling similar situations elsewhere.