Florida Keys — Coral Restoration

Location

Florida, USA, and the U.S. Virgin Islands (USVI)

Background

Since the 1970s, two reef-building corals, staghorn (Acropora cervicornis) and elkhorn (Acropora palmata) have experienced a significant and catastrophic decline throughout Florida and the Caribbean due to a number of causes including disease, coral bleaching, hurricanes, and localized anthropogenic impacts. Both species were listed by the National Marine Fisheries Service as threatened under the Endangered Species Act in 2006, after an extensive review of remaining population sizes.

In 2009, The Nature Conservancy (TNC) received a $3.3 million, 3-year grant from the National Oceanic and Atmospheric Administration (NOAA) through the American Recovery and Reinvestment Act (ARRA) to expand on an Acropora Restoration project. This project is a regional effort designed to aid the recovery of populations of Acropora corals throughout Florida and the USVI, and to provide social and economic benefits for local communities in addition to long-term ecological habitat improvements.

History

In 2000, three A. cervicornis fragments, representing three different genotypes , settled onto a live rock farm owned by Ken Nedimyer of SeaLife. Nedimyer and his daughter began to propagate the coral fragments as part of a 4-H Youth Development project for her high school. Nedimyer later approached TNC and the Florida Keys National Marine Sanctuary about using the fragments for coral restoration purposes. In 2004, TNC and Nedimyer received funding through the NOAA-TNC Community-based Habitat Restoration Grant Program to initiate a pilot study in which corals were grown in the nursery and outplanted to Key Largo reefs after a year.

The success of this project led to a 2006 Expansion Project, funded through the same source. New nurseries were built in Broward County by Nova Southeastern University, Biscayne National Park by University of Miami, and the Lower Keys by Mote Marine Laboratory. Coral fragments for this project were collected from the wild. These fragments were propagated in the nursery for a year and monitored extensively for growth and survivorship. They were then outplanted in each region across reef zones and monitored for growth and survivorship.

In 2009, when ARRA monies became available, the groundwork had already been laid to significantly increase the scope of this project. This project has since expanded to include nurseries along the entire Florida reef tract and in St. Croix and St. Thomas, USVI.

Habitat Restoration

The short-term habitat restoration goal of this project is to enhance coral populations at 34 degraded coral reefs in 8 distinct areas of the coral reef ecosystems of Florida and the USVI by propagating Acropora corals in seafloor nurseries and then transplanting nursery-grown coral fragments to depleted reef sites. The goal is an average direct restoration area of at least 100 square meters per reef site resulting in an overall direct restoration area of at least 3,400 square meters. The dispersal range of coral larvae resulting from sexual reproduction of the restored corals is conservatively 1 kilometer, creating a potential long-term restoration area of 2500 hectares.

Coral Nurseries

With growth rates faster than any other Caribbean coral species and asexual fragmentation as the dominant form of reproduction, Acropora corals can be efficiently propagated using low tech in-water nurseries. Strategically located where natural and human threats are low, in-water nurseries provide a stable setting for highly vulnerable tiny coral fragments to grow and thrive when properly maintained by local coral farmers. When coupled with advanced genetics, nursery-reared corals with high survivorship potential (typically 1 year or more in age) can be outplanted to adjacent degraded reefs to enhance the genetic diversity and population size of remnant coral populations.

There are 18 nurseries within the following distinct subregions and managing partners:

Broward County Nurseries (3): managed by Nova Southeastern University. Broward County Natural Resources Planning and Management Division is also a partner at this site.
Biscayne National Park Nurseries (2): managed by University of Miami, Rosenstiel School of Marine and Atmospheric Sciences.
Upper Keys Nurseries (2): managed by the Coral Restoration Foundation. Both sites are located within the Florida Keys National Marine Sanctuary (FKNMS).
Middle Keys Nurseries (2): managed by the Florida Fish and Wildlife Conservation Commission. These sites are also in the FKNMS.
Lower Keys Nursery (1): managed by Mote Marine Lab. This site is also in the FKNMS.
Key West Nursery (1): co-managed by Florida Keys Community College (FKCC) and Coral Restoration Foundation.
Dry Tortugas Nursery (1): managed by The Nature Conservancy. This site is within the Dry Tortugas National Park and is mostly funded by the National Park Service.
St. Croix, U.S. Virgin Islands Nurseries (3): managed by The Nature Conservancy. University of the Virgin Islands is a partner at this site. Focused on both Acropora cervicornis and Acora palmata.
St. Thomas, U.S. Virgin Islands Nurseries (2): managed by The Nature Conservancy. Primarily focused on Acropora palmata. University of the Virgin Islands is a partner at this site as well.

Nursery set-up and monitoring. Photo © Liz Larson/Nova

At the start of the project, three fragments (10 cm or smaller) were clipped from 20 isolated wild staghorn colonies within each of the six Florida sub-regions and relocated to the established nursery in each sub-region. In addition, natural fragments that were found detatched from the parent colony and unlikely to survive on their own, known as fragments of opportunity, were collected and further fragmented. In the USVI, only fragments of opportunity were being collected per permit requirements.

As nursery fragments grow, they are clipped to create additional fragments, all of which are marked with unique identification codes so they can be traced back to their parent colony. All fragments remained at the coral nursery site until recently, when about 6,000 corals were outplanted onto natural reefs.

Genotyping

The genotypic identity of all wild parent colonies from each sub-region was determined after collection. This genetic marker is a valuable tool that allows long-term tracking of recruitment and proliferation resulting from the restoration sites across Florida and the USVI. This information will be added into the existing genetic library for the species to help determine genetic relationships across Florida and Caribbean sub-regions. All genotyping is conducted by Penn State University.

Monitoring and Maintenance

On a quarterly basis, trained staff and volunteers from each project location assist in the monitoring of the nursery coral colonies for presence/absence of disease, bleaching, breakage, predation, and survivorship.

In addition, the nursery is cleaned on a regular basis. Many species of algae settle on the nursery blocks and compete with the coral. If left unmaintained, the algae could eventually cause the coral fragments to die, particularly when the coral fragments are small or when there are additional stressors such as warm temperatures or predation. Nursery maintenance is conducted on an as-needed basis and the interval varies based on season, nursery location, and number of corals in nursery.

Monitoring was also conducted on parent colonies for the first year after collections. At the time of collection, three un-cut branches were marked with zip ties and measurements were taken from the zip tie to the end of the branch. After one and three months, those same branches were measured to determine approximate growth rates. In addition, the colony was assessed at one month and quarterly basis for the first year for presence/absence of disease, bleaching, breakage, predation, and survivorship.

Following the outplanting event, all outplants will be monitored quarterly using the same criteria. Maintenance will include removal of snails and fireworms and reattachment of broken fragments.

Outplanting

A total of 5,628 individual Acropora colonies that have been raised in the nurseries were outplanted back to degraded reefs throughout Florida and the USVI in April and May 2012. Corals were outplanted at sites that have conditions conducive to their survival. Different genotypes were outplanted within arrays at each site to maximize the chances of successful cross-fertilization once the corals reach spawning size (likely in 2-5 years). Corals were outplanted using methods that have been successful in past outplanting events, including: 1) on a puck securely fastened to the substrate; 2) zip-tied to a nail that has been driven into the substrate, and secured at the base with epoxy; and/or 3) secured with epoxy directly to the substrate. Most nursery managers employed some combination of these methods, depending on how the coral was grown in the nursery, the size and shape of the coral, and the conditions at the outplant site.

The goals for nursery production have been well exceeded and we are working on securing permits to conduct additional outplanting in the fall, when water temperatures have cooled enough to not cause additional stress to the outplants.

A subset of the outplants will be monitored after one month and between 3 and 6 months for presence/absence of disease, bleaching, breakage, predation, and survivorship. In addition, all outplants will be maintained through the removal of predatory snails and worms, cleaning as needed, and reattachment of broken fragments.

Current Status

Approximately 30,000 (with a goal of 12,000) coral colonies are being maintained across 16 nurseries.
New fragments that have been established in the nursery during the first year represent at least 98 different genotypes.
An Outplanting Plan with details on the health criterion, methods, site selection, design, and monitoring, has been developed.

Lessons Learned

This project has been taken from a small pilot study to a larger scale, high production level in about 6 years.
Project partners are testing a variety of techniques to help improve survivorship and growth rates with the idea that more efficiency in the nurseries leads to more restoration work on reefs.
A Coral Restoration Guide (pdf, 426k) is currently being drafted to bring together the knowledge that has been gathered since the beginning of this project.
This project represents a very large partnership between universities, non-profits, and government agencies. Working with this diverse group of partners requires open lines of communication and regular check-ins. Quarterly conference calls have helped keep everyone on the same page and allowed nursery managers the chance to communicate directly with each other. Also, nursery visits and occasional face-to-face meetings keep partners accountable and engaged.