Survey of Deepwater Coral/Sponge Assemblages and their Susceptibility to Anthropogenic Impacts in Olympic Coast National Marine Sanctuary

Olympic Coast National Marine Sanctuary
May 22-June 4, 2006

Goal of the Research Cruise

video iconRed Tree Coral Video (Format: Flash)

Deepwater coral colonies host many organisms: feather stars, sea anemones, cup corals, brachiopods, sponges. The large pink coral is x. Photo: Olympic Coast NMS
Deepwater coral colonies host many organisms: feather stars, sea anemones, cup corals, brachiopods and sponges. (Photo: Olympic Coast National Marine Sanctuary)
A research team representing several NOAA organizations has completed a research cruise aboard the NOAA ship McArthur II in Olympic Coast National Marine Sanctuary. The project’s goals were to locate seafloor communities of sponge and coral, document fish and invertebrate species associated with the coral and sponge communities and look for signs of damage to the communities caused by fishing and other human activities.

Background

decorator crab on a gorgonian coral
A decorator crab adorns this gorgonian. (Photo: Olympic Coast National Marine Sanctuary)
The continental shelf and submarine canyons of Olympic Coast National Marine Sanctuary are highly productive, supporting diverse seafloor communities that contribute to important rockfish, flatfish and other fisheries.  Recent acoustic surveys conducted in these waters show the presence of rocky bottom and steep relief believed to harbor deep-sea coral and sponge assemblages.  Coral and sponge communities are often associated with shallow tropical waters, however, many recent studies around the world show that they also occur in deeper, cold-water habitats in both northern and southern latitudes. 

fish with coral
Darkblotched rockfish nestled in the branches of a gorgonian soft coral, tentatively identified as a Primnoidae. (Photo: Olympic Coast National Marine Sanctuary)
These habitats are valuable as sites of recruitment for commercially important fishes.  Yet recent studies have shown how the gear used in offshore bottom fishing, as well as other commercial operations on the seafloor (such as cable trenching), can severely disturb seafloor communities.  Due to their exposed structure, slow growth, long life spans, and slow recovery rates, deep-sea corals and sponges may be especially vulnerable.  Potential effects of fishing and other commercial operations in these sensitive habitats, and the need to define appropriate strategies for the protection of these resources, are high-priority management issues for the sanctuary.

The Cruise

In this project, a team of scientists representing Olympic Coast National Marine Sanctuary, the National Centers for Coastal Ocean Science, NOAA’s Northwest Fisheries Science Center and the private research firm, Aquanautix Consulting conducted remotely-operated-vehicle (ROV) surveys to document the presence and condition of coral and sponge communities in the Olympic Coast National Marine Sanctuary.

research team
(left to right) Mary Sue Brancato, Peter Etnoyer, Jeff Hyland and Ed Bowlby review dive sites aboard the McArthur II. (Photo: Olympic Coast National Marine Sanctuary)
From the NOAA Research Ship McArthur II, the team deployed the Canadian ROV ROPOS operated by the Canadian Scientific Submersible Facility of Sidney, British Columbia. Primary funding has come from NOAA’s Office of Ocean Exploration, NMSP and the National Centers for Coastal Ocean Service. Additional funding was provided by OCNMS, NCCOS, and the National Undersea Research Program.

The research team was comprised of principal investigators, Ed Bowlby (OCNMS), Mary Sue Brancato (OCNMS), and  Dr. Jeff Hyland (NCCOS). Other researchers include coral specialist Peter Etnoyer (Aquanautix Consulting) and marine biologist Curt Witmire, Northwest Fisheries Science Center. The ROPOS ROV team was led by Keith Shepherd of the Canadian Submersible Science Facility.

cup coral
A giant cup coral amid feather star tendrils. (Photo: Olympic Coast National Marine Sanctuary)
Operating on sample stations between one and 20 miles from shore in Olympic Coast National Marine Sanctuary, the team worked around the clock to collect video, photographs and live samples from depths between 80 and 600 meters. In one dive, the ROV operated continuously for over 52 hours, a record for dive duration for ROPOS and CSSF.

The Results

Soft coral fields encountered

cup coral
Coral polyps on this gorgonian are arranged in groups of eight. (Photo: Olympic Coast National Marine Sanctuary)
Results from the surveys were dramatic. Scientists encountered large fields of erect soft corals known as “gorgonians” with individual colonies as high as one meter.  Many of the coral and sponge communities show thriving populations of invertebrates and fishes using the coral structures as habitat. Rich stands comprised of several coral species support invertebrates as diverse as tubeworms, shrimp, brittle stars, sea slugs, crabs, colonial sea anemones and feather stars. Many of the communities form aggregation sites for rockfish from several species, including areas with pregnant females. Also, on several occasions, researchers saw egg cases of sharks attached to the coral colonies.

Interesting coral findings

rockfish in coral
Coral communities are aggregation sites for important fish species, including many rockfish. A  rosethorn rockfish, fat with offspring awaiting birth, hunkers down among giant cup and Lophelia corals. (Photo: Olympic Coast National Marine Sanctuary)
Corals observed also include giant cup corals, branching soft corals such as “bubblegum coral” and the stony coral Lophelia, only recently discovered within the sanctuary and the Washington coast. At one location researchers spent hours surveying a massive house-sized boulder that hosted many coral species and teemed with invertebrates. At the base of the rock they found a large mound of Lophelia coral rubble with a deposit representing decades of growth. Live Lophelia was found on the rock face and atop the rubble.

Evidence of disturbance

lophelia
A single Lophelia pertusa, a true stony coral, grows on a mound of Lophelia skeletons. Unidisturbed Lophelia mounds can accumulate for centuries, creating deposits of calcium carbonate and habitat for other animals, like this squat lobster. (Photo: Olympic Coast National Marine Sanctuary)
Portions of the seafloor unfortunately show evidence of disturbance. Derelict gear, trawl tracks and damaged habitat have been common within the study areas. In some cases, communities appear to have been reduced to scattered fields of skeletal fragments. Boulders and cobble show signs of being tumbled, their surfaces denuded of living communities. Researchers dubbed one site a “coral graveyard” upon finding a broad field of Lophelia and cup coral rubble, as well as stalks and thick broken branches of what appeared to have been large soft corals.

Future Plans

shark case on a gorgonian coral
The egg case from a cat shark firmly attached to the stalks of a gorgonian coral colony. (Photo: Olympic Coast National Marine Sanctuary)
Results of this project will be analyzed to establish links between specific seafloor types and coral and sponge habitats. New areas identified as coral and sponge communities will be mapped and monitored by the sanctuary. Ideally, the survey data will be used by fisheries managers considering boundaries for areas designated as “essential fish habitat” for depleted and declining stocks of rockfish and other commercially-important species.

Contact Information

shrimp on a coral
The shining eye of a shrimp clinging to a tangle of gorgonian stalks. At left, a brittle star shows its leg. (Photo: Olympic Coast National Marine Sanctuary)
Research Coordinator
Ed Bowlby
NOAA Olympic Coast National Marine Sanctuary
115 East Railroad Ave., Suite 301
Port Angeles, Washington  98362
Telephone:  360/457-6622, Ext 17
Email:  ed.bowlby@noaa.gov

Education and Outreach
Robert Steelquist
NOAA Olympic Coast National Marine Sanctuary
115 East Railroad Ave., Suite 301
Port Angeles, Washington  98362
Telephone:  360/457-6622, Ext 19
Email: robert.Steelquist@noaa.gov 

Affiliated National Marine Sanctuary website:
Olympic Coast National Marine Sanctuary

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