Cold-Water Corals or Deep Sea Corals
What are cold-water corals?
Cold-water corals, also referred to as deep-sea
corals, include scleractinian corals (stony corals), antipatharians
(black corals), hydrocorals and octocorals (gorgonians, soft corals
and sea pens). These organisms may occur as solitary individuals
(e.g., solitary scleractinian corals) and also can form both reef-like
structures and thickets that provide habitat for numerous species.
Unlike many shallow water tropical corals, 
cold-water
corals lack symbiotic algae (zooxanthellae) due to the limited
penetration of sunlight to these depths, and rely on plankton
and organic matter for much of their energy needs.
Where are cold-water corals found?
Cold-water corals are found in cold oceanic
waters worldwide and occur from near the surface to 6000 meters
in depth, but are most commonly found between 50 meters to 1000
meters. Within the U.S. exclusive economic zone (EEZ), cold-water
coral habitats are found in the Atlantic and Pacific Oceans and
the Gulf of Mexico primarily along continental shelves, slopes,
canyons, ocean ridges and seamounts. Scientists have identified
a number of locations in the U.S. EEZ with extensive coral populations,
including:
- Lophelia coral banks off the SE Coast;
- Deep-water reefs of Lophelia pertusa and Enallopsammia profunda on the western edge of the Blake Plateau off South Carolina and Georgia, along the base of the Florida-Hatteras slope in the Straits of Florida, and also in patches from Cape Lookout through Florida;
- low-relief Lophelia mounds on the upper De Soto Slope in the northeastern Gulf of Mexico;
- Oculina Banks off the eastern Florida shelf;
- Habitat forming gorgonian corals (Primnoa, Paragorgia and Calligorgia spp) along the continental shelf and slope along the Gulf of Alaska and Aleutian Islands;
- Deep-sea precious corals in Hawaii;
- Deep-water Primnoa resedaeformis and Paragorgia arborea aggregations on the upper and middle slope faunas in the canyons south of Georges Bank and on four New England seamounts;
- Deep water gorgonians (Paragorgia) on the tops of the ridges of Davidson Seamount, 120 km southwest of Monterey
Why are cold-water corals important?
Cold-water corals may serve as habitat for
rich and diverse fish and invertebrate communities, including
some commercially important fisheries species. In some areas they
have been shown to provide enhanced feeding possibilities among
aggregating species, a hiding place from predators, a nursery
area for juveniles, and substrate for invertebrates.
For instance, in the Oculina Banks off Florida Reed
(2002) found over 20,000 individual invertebrates living among
the branches of the ivory tree coral (Oculina varicosa)
colonies, proclaiming that the biodiversity of the deep Oculina
reefs is equivalent to 
shallow
tropical reefs. Furthermore, Koenig (2001) found a clear relationship
between economically valuable fish populations (e.g., grouper,
snapper, sea bass, amberjack) and the condition (dead, sparse,
and intact) of the Oculina coral.
In Alaska, Krieger and Wing (2002) identified several megafauna groups that feed on the coral polyps and valuable rockfish, shrimp, and crab species use the coral branches for protection from predators.
Cold-water corals serve as foraging areas in the Northwestern Hawaiian Islands for the critically endangered Hawaiian Monk seals.
Cold-water corals may also serve as important indicators of past climate. Living deep-sea corals have been dated to be more than a hundred years old and stable isotopes incorporated in their skeletons give clues to past temperatures. Dead corals forming deep banks have been radiocarbon-dated to be > 40,000 years.
What are the major threats?
The major threat to cold-water coral ecosystems
appears to be fishing associated damage from bottom trawling.
In addition to trawling, other bottom-set fishing gears, such
as bottom long-lines and gill nets, as well as oil and gas exploration
and drilling, mineral mining, cable laying over cold-water coral
habitat and sedimentation may also damage coral habitat.
Unlike many shallow-water tropical corals, cold-water corals grow, mature and recruit at very slow rates (some deep-sea corals are estimated to be hundreds of years old). Living cold-water reefs have been aged up to 8,000 years, and the corals that form them grow at rates of 4 – 25 mm/year compared to shallow tropical corals that can grow up to150 mm/year. These characteristics make cold-water corals highly susceptible to anthropogenic and natural processes and regeneration or recovery might take decades to centuries for a damaged reef to regain its ecological function.
What are we doing to protect cold-water corals?
The primary conservation measures for cold-water corals in the
U.S. EEZ consist of managing fishery impacts through Fishery Management
Plans, and providing protection for a broader set of impacts by
designating certain areas as National Marine Sanctuaries, both
implemented by NOAA. Under existing authorities NOAA Fisheries
Service can regulate:
- fisheries for corals/sponges;
- fisheries in which there is bycatch of corals/sponges; and
- corals/sponges that have been determined to be EFH or HAPC.
The Minerals Management Service of the Department of the Interior also regulates oil, gas and mineral exploration and development in the U.S. EEZ.
The Caribbean, Gulf of Mexico and Western Pacific Fishery Management Councils, under the guidance and advice of NOAA Fisheries Service, have identified and designated some coral habitats as Essential Fish Habitat (EFH) in several Fisheries Management Plans (FMP). Management measures have been taken to reduce adverse fishing impacts on these designated coral habitats, which include some cold-water coral species (e.g., Oculina).
The North Pacific Fisheries Management Council has made the identification of cold-water corals a priority on the designation of their HAPC's to note particular attention to these vulnerable habitats. HAPC's may be designated within identified and described EFH to better focus protective measures for important habitats
The South Atlantic Fishery Management Council established the Oculina Habitat Area of Particular Concern (HAPC) in 1984 through the FMP Corals and Coral Reefs, prior to recognizing it as EFH in 1998. Its boundaries were expanded to 1029 km2 in 2000. The Oculina Research Reserve was one of the first deep-sea coral banks in the world where bottom trawling, traps, long-lining and dredging were banned
The Western Pacific FMC is the only council to have banned trawling throughout its region and to regulate harvest of a cold-water coral through a FMP. Black and precious corals are harvested in Hawaiian waters and the EEZ and used in jewelry manufacture.
Although all the Councils have not yet designated deep-sea coral specifically as EFH, several Councils are currently considering proactive measures to protect cold-water corals from adverse fishing impacts.
Information Needs
NOAA and our partners have just begun to identify,
characterize and study cold-water coral communities and the impacts
of human activities on these ecosystems. Although we have identified
a number of important areas containing populations of cold-water
corals, there are certainly other areas of cold-water corals in
the U.S. EEZ that have not been documented. At this time, we do
not have detailed information on fishing activities within known
cold-water coral habitats. Some of the priorities for cold-water
corals include:
- Identify, map, and characterize cold-water coral ecosystems within the U.S.;
- Conduct research on the ecology, physiology, biogeography and taxonomy of cold-water corals including species inventories, growth and reproductive studies and food web and species interaction studies;
- Conduct research on the vulnerability and resilience of deep coral habitats to various anthropogenic threats;
- Evaluate the potential uses of specific cold-water coral species as indicators of climate change; and
- Enhance NOAA’s technological capabilities, including furthering the development of new technologies, to access and study cold-water coral.
Deep-Sea Coral Collection Protocol
The Deep-Sea
Coral Collection Protocol provides an overview
of techniques and approaches used by field scientists in documenting,
collecting, preserving, labeling and shipping deep sea coral
specimens.
It includes a general overview of techniques to assist in identification
such as branching patterns and sclerites in octocorals, coral
reproduction, and genetic methods. A general discussion of ecological
assessment techniques incorporating still images and video photography
is also presented.
NOAA Petitioned to Protect Deep Sea Corals
In March, 2004 NOAA was petitioned by the non-governmental organization Oceana to take action on protecting deep sea corals. NOAA Fisheries Service is currently in the process of responding to the petition and a Deep Sea Coral Interagency Team has been formed to address the issues raised in the petition.
