Innovative Coral Restoration Begins in Hawaiʻi After Ship Grounding

A promising and emerging coral restoration technique is being tested in the coastal waters of Hawai‘i for the first time.

Scientists are testing rubble stabilization as a coral restoration technique in the coastal waters of Hawai‘i for the first time, with promising results. It involves securing loose, broken parts of the reef to the seafloor so corals have a stable surface to grow. The process has given a disintegrated reef system a new chance to recover.

In November 2022, NOAA and State of Hawai‘i scientific divers were on a monitoring mission off the southwestern coast of O‘ahu. They discovered that the coral habitat at the site of a ship grounding 12 years prior was not recovering in the way they’d expected and hoped. One of the main issues was that sections of the pulverized reef were still covered by loose rubble. Determined to figure out another approach, they started researching. They came across an innovative method that had not been used in coastal Hawai‘i yet. Questions arose: Would it work in our high energy wave systems? Would it improve the chances that new corals will survive and grow? And how would they learn how to do it?

Restoration in the Wake of Ship Grounding

The area was damaged in 2010 by the M/V Vogetrader cargo ship when it ran aground. It damaged almost 3,500 square meters of vibrant coral reef—important habitat for fish and other marine species. When events like this happen, NOAA’s Damage Assessment, Remediation, and Restoration Program evaluates harm to marine resources, coastal habitats, and recreation before putting forth plans for restoration.

The damage assessment documented the loss of an estimated 100,000 coral colonies. The ship’s hull had gouged and disintegrated the reef framework itself into a field of rubble. In 2013, habitat restoration began with the removal of 354 square meters of rubble and outplanting of 643 coral colonies.