Feds: Removing shipwrecks good for reefs

  • Photo courtesy U.S. Geological Survey

    The arrows in this image point to mouths of individual corallimorphs. Each corallimorph mouth is surrounded by a corona of tentacles, and the organisms harm the coral reefs upon which they live.

LIHUE — The remnants of the 1800s freighter Pele lie off the coast of Kauai’s South Shore, and though there’s not much of her left, shipwrecks like Pele could offer answers to coal research.

That’s according to a new U.S. Geological Survey study, which shows the removal of shipwrecks and application of chlorine may help with an invasive anemone causing problems for corals in Hawaii.

And it’s not just ancient wrecks that are being studied.

“Ships are often sunk deliberately to promote diving or recruitment sites for reef organisms, but our study provides a cautionary note for such practices in tropical marine systems,” said Thierry Work, a USGS scientist and lead author of the study.

That’s because invasive anemones called corallimorphs (CM) thrive on coral reefs that have been degraded by environmental or man-made disturbances, according to Work.

The research for the USGS study took place at Palmyra Atoll National Wildlife Refuge in the Central Pacific, where researchers found CM thriving on coral reefs near a shipwreck.

Starting in 2007, USGS scientists and partners surveyed the CM-infested coral reef before and after removal of the shipwreck and found CM-infested areas were reduced from 21 percent of the reef to 14 percent of the reef.

The other key to the study was exposing CM to chlorine, which nearly eradicated the organism from small plots of about 100 square feet after a few days. The plots have remained CM free for at least 15 months, allowing native flora and fauna to regrow.

That marks the first time that shipwreck removal was shown to have beneficial effects for reef recovery from CM, according to the USGS.

“Scaling up the control methods tested in our study might provide hope that the Palmyra corallimorph could be contained or possibly eradicated,” Work said. “Coupling these methods with shipwreck removal could potentially help control infestations at other sites.”

On Kauai, the Hawaii Invasive Species Council’s Aquatic Invasive Species Response Team has been working on the eradication of CM for several years, and has much of the invasive species under control.

The organisms were intentionally introduced to state waters on Kauai through the aquarium trade, according to the Kauai Invasive Species Committee.

Protection of the state’s reefs against organisms like CM is paramount for the health of the entire ecosystem around the islands, according to scientists, and the recent USGS study is just one of many focused on the conservation of the coral reef ecosystem.

“Coral reefs are home to a significant diversity of marine life, provide valuable economic and environmental services to millions of people, buffer shorelines from erosion and waves and can serve as a resource for the development of new medicines,” Work said.

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Jessica Else, environmental reporter, can be reached at 245-0452 or jelse@thegardenisland.com.

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