Homeward Bound: Mesophotic Corals Returned to Flower Garden Banks National Marine Sanctuary

By: Erin Spencer

September 29, 2026

This August, 56 corals made a long journey home.

After being studied in NOAA laboratories, octocorals originally collected as fragments from the mesophotic, or twilight zone were loaded onto the RV Pelican and transported offshore near Flower Garden Banks National Marine Sanctuary. Experts cared for the corals for up to four years to learn about the corals' growth, feeding, and reproductive cycles in support of restoration efforts. After being returned to the sites they were collected from, the corals will continue to provide important data about how these animals grow in healthy seafloor habitats.

coral fragment containers attached to the coral elevator for deploment of the ship — Coral fragments are placed on the coral elevator, ready to be lowered to the seafloor for outplanting. Photo: Shannon Ainsworth/TESA

This mission represents a milestone for the Mesophotic and Deep Benthic Communities (MDBC) restoration portfolio, a collection of projects led by NOAA and the Department of the Interior on behalf of the Deepwater Horizon Open Ocean Trustees. The projects are restoring mesophotic and deep coral habitats affected by the 2010 Deepwater Horizon oil spill, which injured more than 770 square miles of seafloor habitat in the Gulf of America. The MDBC team spends many days at sea each year to complete crucial field work and conduct restoration activities—including in and around Flower Garden Banks National Marine Sanctuary.

The sanctuary's healthy mesophotic communities show scientists what thriving habitats can look like, providing a key comparison to areas in the Gulf injured by the spill. By returning lab-reared corals to sites near where they were first collected, the restoration team can track their growth over time, which helps inform restoration efforts.

two people attaching coral fragment containers to the coral elevator — Members of the science team prepare the coral elevator to deliver coral fragments to the seafloor for outplanting. Photo: Daphne Torres/TESA

The outplanted corals were from five species: Swiftia exserta, Muricea pendula, Thesea nivea, Placogorgia sp., and Callogorgia sp. The coral fragments were collected on expeditions between 2022 and 2025 and cared for in labs in Charleston, South Carolina, and Galveston, Texas. Before the recent trip, veterinarians made sure the coral colonies were healthy enough to return to the seafloor. At sea, the corals were placed in a specially designed "coral elevator" and lowered to sites within 1 kilometer of where they were collected. Then, a remotely operated vehicle (ROV) operated by a pilot onboard carefully navigated each coral fragment home.

This is only one of a few times mesophotic corals have been kept in aquaria and returned to the seafloor: Last year, the team outplanted 24 colonies from the Galveston lab. The 2026 mission revisited those corals to see how they were faring, and found exciting results. At a site north of Geyer Bank, for example, all corals outplanted in 2025 survived—and even grew!

outplanted coral on the seafloor — *Callogorgia* coral fragments are outplanted on the seafloor near other *Callogorgia* corals at Ewing Bank. Photo: NOAA, Marine Applied Research & Exploration, National Marine Sanctuary Foundation

The mission featured a talented team from NOAA, USGS, the University of Rhode Island, and Marine Applied Research and Exploration. In addition to outplanting the corals, the team conducted ROV video surveys, collected biological and water samples, and recovered settlement tiles. Ultimately, they completed all of the objectives planned for the mission, and are already planning to visit the outplanting sites on a future mission.

For the 56 corals, the journey home is complete. Each represents one step towards a larger goal: restoring mesophobic coral communities across the Gulf.

Erin Spencer is the Gulf restoration communications manager for the National Marine Sanctuary Foundation