Coral & Live/Hard Bottom Habitat

Under the authority of the Magnuson-Stevens Act, the Council conserves and manages bottom habitat resources in the EEZ, from 3 to 200 miles from the North Carolina/Virginia border through the Florida Keys. The management of these bottom habitat resources is a collaboration between the Council and other regional stakeholders, including National Marine Sanctuaries, and state and local governments.

FKNMS_purple sea rod (CORIS).jpgCoral reefs and associated habitats are complex systems that are culturally, economically, and scientifically significant in the South Atlantic. Coral reefs are composed of a diverse assemblage of sessile and mobile benthic animals, as well as free-swimming organisms that interact among them and with their physical environment. In addition to biological reefs, which are formed by corals, submerged rock formations (hardbottoms) are often colonized by reef species (Photo credit: FKNMS/CORIS).

Corals can be characterized using the following terms: deep water species, shallow water species, stony corals, octocorals, hermatypic, and ahermatypic. The Fishery Management Plan for Coral, Coral Reefs and Live/Hard Bottom Habitat of the South Atlantic Region (Coral FMP) defines coral reefs as hardbottoms, nearshore hardbottoms, deepwater hardbottoms (including deepwater banks), patch reefs, and outer bank reefs. Note that although attempts have been made to generalize discussion of the different types of habitats managed under the Coral FMP into definable types, these habitat resources include many more than the distinct categories listed below:

Hardbottoms are found on wide bathymetric and geographic scales. These formations are present in nearshore, mid- and outer-shelf areas. Hardbottoms are also called hard banks, organic banks or simply banks. Hardbottoms can support coral communities; however, they generally lack the coral diversity, density, and reef development of patch and outer bank reefs. Hardbottom may include some hermatypic corals and are widely distributed in the management area. Biota usually include a thin veneer of live corals, often covering a rock outcrop or a relic reef, and associated benthos (e.g., sponges, tunicates, holothurians) in an assemblage with low relief. Hardbottoms are also called live bottom, hardgrounds, or pinnacles (when found in a non-bank setting).

Nearshore Hardbottoms
The hardbottom reefs located off of the southeast Florida coast are the primary natural reef structures at 0-4 m depths. The habitat complexity of hardbottom is expanded by colonies of tube-building polychaete worms. These reefs help stabilize nearby beaches and are utilized by over 500 species of fishes, invertebrates, and plants. Hardbottom habitats are often centrally located between mid-shelf reefs to the east and estuarine habitats within inlets to the west. Because of this, they may serve as settlement habitats for immigrating larvae or as intermediate nursery habitats for juveniles emigrating out of inlets. Nearshore reefs reduce wave and current energy and protect against coastal erosion.

Deep water hardbottoms (including Deep water Banks)
May-June-2005-067.jpgIn deeper waters, large elongated mounds called deepwater banks, hundreds of meters in length, often support a rich fauna compared to adjacent areas. Deepwater corals (e.g., Lophelia pertusa and Enallopsammia profunda) and coral reefs are widespread, occurring in 350-500 m depth on the Blake Plateau off North Carolina and in the Straits of Florida in 560 to 600 m including areas along the Miami Terrace and Escarpment. Several of the areas have been proposed as Coral Habitat Areas of Particular Concern. These corals are slow growing and have lengthy recovery periods when damaged. Deepwater habitat types include areas and resources commonly termed coral thickets, deepwater banks, lithoherms, haystacks, deep sea mounds, and dead coral mounds, in addition to any hardbottom area that supports solitary deepwater corals. The ahermatypic branching corals, Lophelia pertusa and Enallopsammia profunda, are the chief contributors to structure and habitat. Sponges and other invertebrates also add to bottom relief, species diversity, and total available habitat. These ahermatypic corals may contribute to the habitat value of deepwater marine systems by providing framework and promoting entrapment and accumulation of sediments and skeletal debris (Photo credit: UNCW).

Black corals (Antipathes sp.) have been found along hardbottom substrate in waters that extend from 65 m to 104 m depth. Although this particular taxon is widespread, black corals have a patchy distribution and generally occur in low abundance. All black corals are characterized by slow growth, delayed first reproduction, limited larval dispersal and low rates of recruitment, low natural adult mortality, and long life. Black coral colonies inhabit areas where few other species occur and they provide essential habitat for several species of fish and invertebrates.

Shelf-edge banks occur off central eastern Florida at depths of 70 to 100 m, with relief up
to 25 m and covered with massive, contiguous colonies of Oculina varicosa (1 to 2 m in height). Some of the pinnacles are covered entirely with dead Oculina debris. At 3 to 50 m depths solitary colonies (<30 cm diameter) of Oculina varicosa grow on limestone ledge systems (1 to 3 m relief) that parallel the coast of Florida.

Patch Reefs
Patch reefs are irregularly distributed clusters of corals and associated biota located in the management area only along the seaward (southeast) coast of the Florida Keys. They occur as dome-type patches on the leeward side of outer bank coral reefs (see description below) or as linear-type patches that parallel bank reefs in curved patterns. The latter support flora and fauna, including elkhorn coral (Acropora palmata), which more nearly resembles the bank reefs. Patch reefs include hermatypic reef-building corals plus ahermatypic species. Most patch reefs occur 3 to 7 km (1.6 to 3.8 nm) offshore between Miami and the Dry Tortugas on the inner shelf (less than about 15 m). Vertical relief ranges from less than 1 m to over 10 m. However, while less studied, patch reefs also occur off the east coast of Florida as far north as Palm Beach County.

Outer Bank Reefs
The principal reef systems of the central and southeastern region of Florida Atlantic coast are characterized by two subregions: (1) reefs located offshore of mainland southeast Florida (from Cape Canaveral to Miami) and (2) the Florida Reef Tract (from Miami to the Dry Tortugas). The latter subregion is largely protected under the Florida Keys National Marine Sanctuary (FKMNS) Act (Public Law 101-605, 16 November, 1990), which designated 2,800 nm² as a National Marine Sanctuary.

Through FKNMS zoning, 18 reef areas are designated as Preservation Areas, and there are two Ecological Reserves (Western Sambo and Dry Tortugas) and four restricted Special Use Zones designated for research only (Conch, Tennessee, Looe Key, and Pelican Shoal). The FKMNS' rigorous outreach and education program has facilitated reef protection and restoration efforts and is highly successful.

Outer bank reefs include ahermatypic and hermatypic species in a complex assemblage often with greater vertical relief than patch reefs. In the Florida Reef Tract outer bank reefs are primarily shoreward of the 18 m (60 ft) depth contour. Biota always exhibits zonation, with the number and type of zones dependent upon the height of the coral substrate, the location of the reef, and the stresses present.

BigSponge(NOVA).jpgThe reefs offshore mainland Florida are characterized by three parallel reef lines. The classic reef distribution pattern for central and southeastern waters of the Florida Atlantic coast consists of an inner reef in approximately 5 to 8 m of water, a middle patch reef zone in about 9 to 15 m of water, and an outer reef in approximately 18 to 30 m of water. They are generally linear, terrace-like features, separated by large sand deposits. Although there is a large variety of hard coral species growing on the reefs north of Miami, these corals are no longer actively producing reef features. The reef features seen north of Miami have been termed "gorgonid reefs" because they support such an extensive and healthy assemblage of octocorals. Florida is the only state in the continental U.S to have extensive shallow coral reef formations near its coast. The outer reef communities are the least studied, and increased conservation, protection, and general awareness are needed (Photo credit: Nova Southeastern University, NCRI).

The Outer Shelf Reefs offshore North Carolina are found at depths between 50-200 m along the edge of the continental shelf. They serve as refuge for fish and invertebrates in the otherwise barren landscape of the open ocean, providing shelter from predators and plentiful food resources.

Solitary Corals
A coral organism composed of a single polyp. This category often lacks topographic relief as its substrate. Throughout much, if not all of the management area, research has located bottom communities which include corals as a minor component of biotic diversity. Although these solitary corals contribute bottom relief and habitat to communities throughout the fishery conservation zone, they apparently comprise a minor percentage of the total coral stocks in the management area.

Live Rock Aquaculture

Live Rock - Living marine organisms, or assemblage thereof, attached to a hard substrate, including dead coral rock (excluding individual mollusk shells).
The Council established a live rock aquaculture permit and management system under Amendment 3 to the Coral FMP (1995). This provided live rock harvesters with a legal alternative to removal of natural bottom.
To identify cultured rock it is necessary to require use of geologically distinguishable substrates in order to prevent individuals from harvesting natural bottom and landing it as aquacultured rock. Any illegal harvest would result in a net loss of bottom habitat. This requirement, along with other criteria presented in the general permit, was adopted to ensure that aquaculture operations do not degrade, damage or negatively impact the surrounding habitat.
Aquaculture sites may not exceed one acre and material deposited on the site may not be placed on naturally occurring reef outcrops, limestone ledges, coral reefs, or vegetated areas. In addition, aquacultured rock must be placed by hand or lowered under restraint from an anchored vessel. Aquacultured rock may be indelibly marked or tagged.