Restoring corals after physical damage from vessel groundings and natural disasters

By: Sean Griffin, Marine Habitat Resource Specialist, NOAA Restoration Center

Since 2006, the NOAA Restoration Center has performed restoration at 142 sites in Puerto Rico and the U.S. Virgin Islands and reattached over 60,000 corals, many of which are listed as endangered or threatened.

A photo on the left shows a tall fishing vessel in shallow waves with vegetated islands in the background. A photo on the right is an aerial view of a sailing vessel beached in shallow tropical waters along a rocky coast.
A variety of vessels can become stuck on shallow coral reefs. First the vessel and any debris must be removed. Then the reef can be restored by reattaching corals. Photo credits: NOAA Restoration Center (left), United States Coast Guard (right)


Coral reefs can be damaged by both human activities and natural events. For example, vessel groundings, derelict fishing gear, hurricanes, and earthquakes have all damaged corals around Puerto Rico and the U.S. Virgin Islands (St. Thomas, St. Croix, and St. John). Recognizing the capacity and funding needs for an emergency response team, NOAA has partnered with the Puerto Rican and U.S. Virgin Islands governments and a local private business since 2009 to rapidly respond to these emergencies. One critical step in this process is a notification network, consisting of the U.S. Coast Guard, salvers, and local communities, to report grounding incidents. This notification system has allowed rapid mobilization of personnel onsite, while the vessel is still aground on the reef. In many of these cases, the team has been able to provide feedback to the salvers to minimize further impacts during vessel extractions, saving countless corals.

A photo on the left shows large chunks of brown coral lying on the seafloor and a photo on the right shows a brown coral head with white and turquoise damaged areas.
To prevent further damage and to restore reefs, debris needs to be cleared from the site and coral fragments reattached to substrate. Photo credit: NOAA Restoration Center.

Divers conduct an initial assessment to determine resources impacted, options for caching broken corals, and locations to conduct restoration operations safely. Some sites are too exposed to weather and swells, and corals are reattached elsewhere. During reattachment, deckhands mix cement topside in five gallon buckets and lower the buckets to divers. Divers use this cement to reattach the broken corals to stable parts of the reef avoiding any live corals or benthic organisms.

Table with data of NOAA grounding response activities, including number of corals reattached, in Puerto Rico and U.S. Virgin Islands since 2009.
Summary of NOAA grounding response activities in Puerto Rico and U.S. Virgin Islands since 2009. *In 2014, an additional 8 Caribbean coral species were included as threatened on the Endangered Species Act list. Hurricanes Maria and Irma directly impacted Puerto Rico and the USVI in 2017.

Funding for this work is provided by several NOAA programs. In addition to physical impact response, the funding has served as a vehicle for additional restoration, research, and monitoring activities in the region and as leverage to ensure private parties and insurance companies directly cover the cost of emergency restoration at multiple sites. The capability to perform immediate post-grounding site assessments and have an approved/permitted contractor on site has led to multiple benefits for coral reefs in Puerto Rico and the U.S. Virgin Islands.

An aerial view of a deserted tropical coastline. A large white boat is halfway submerged in shallow water. A smaller yellow boat sits on the surface next to it.
Vessel groundings can include recreation vessels that sink below the surface onto the reef. Photo credit: U.S. Coast Guard.

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