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In the Spotlight

A Particular Concern: Protecting Deep-Sea Corals

A NURP-led expedition reports on the success of efforts to preserve a national treasure.

By Taylor Sisk

A blue angel fish is nearly invisible against the live ivory tree coral Oculina.

Figure 1: Live Oculina varicosa, the ivory tree coral, with Holocanthus bermudensis, the blue angelfish. Photo credit: NURP/UNCW

Twenty miles off the coast of Florida, stretching from Daytona Beach down to Ft. Pierce, close to the edge of the continental shelf, deep-water coral reefs of Oculina varicosa, or the ivory tree coral (Figure 1), lie 150 to 300 feet beneath the water’s surface. Oculina are quite unique, the only known stand of their variety in the world. As such, in 1984, the South Atlantic Fishery Management Council, under the advice and guidance of NOAA Fisheries, designated a 92-square-nautical-mile portion of these reefs as the Oculina Habitat Area of Particular Concern (Oculina HAPC). In 1994, the Oculina HAPC was closed to all manner of bottom fishing and was designated as the Experimental Oculina Research Reserve. In 2000, the area was expanded to 300-square-nautical-miles and prohibited all gears that caused mechanical disruption to the habitat.

Walk into a bait shop along the coast of Florida, though, and odds are the fishing map you pull from the rack will have little or no indication of the Oculina HAPC, no mention of fishing restrictions and no acknowledgement of an area closed to specific types of fishing. And that’s a problem.

It certainly doesn’t make John Reed’s job any easier. Reed is a marine scientist with the Harbor Branch Oceanographic Institution (HBOI) in Ft. Pierce, Florida. In spring of 2003, Reed served as co-principal investigator on an eight-day expedition led by NOAA's Undersea Research Program (NURP) Center at the University of North Carolina at Wilmington, in collaboration with NOAA Fisheries and the National Aeronautics and Space Administration (NASA). The purpose of the mission was to learn more about the Oculina reefs. Reed has been studying Oculina for 25 years. It was he, in fact, who nominated the Oculina reefs as an HAPC.

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Oculina...“are like the redwood forests. These reefs are thousands of years old. And there are no others like them in the world.”

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The discovery

“When I was first out of graduate school,” says Reed, “I was hired at HBOI, and this was just after they’d discovered the deep-water Oculina reefs using a submersible. They had come across one of these 60- to 100-foot-high deep-sea coral reefs. “My first study, in 1976, was to see what lived in the coral, what used it for habitat. I began to study the invertebrates, and what I found out was that a small coral colony with a head the size of a basketball could hold up to over 2,000 individual animals and hundreds of species, including worms, crabs, shrimp and fish. It was an incredible biologically diverse environment that we had never known about before.

Organisms use brown or dead Oculina as well as white living Oculina for habitat.

Figure 2: Whether dead (brown) or alive (white) – Oculina serves as a high-relief habitat for many organisms, including some commercially important fish species. Photo credit: L. Horn, NURP/UNCW

“By 1980, we realized that this was a totally unique habitat found nowhere else in the continental United States. And possibly nowhere else in the world (Figure 2).

“At the same time, I began to look at how fast the coral grows. So my next study was to see how old the colonies’ heads were. We were seeing coral heads the size of a Volkswagen Beetle. I did a study over two years and found that they actually grow very slowly, about a half an inch a year. So a large head could easily be 100 to 200 years old. Then I did a coral core sample into one of these reefs and determined the age of the dead coral that came from the inside of the reef.”

What Reed and his colleagues learned by radiocarbon dating the dead coral that came from the inside of the reef was that the coral was around 10,000 to 12,000 years old, meaning it began life near the end of the last Ice Age.

“We also came to realize,” Reed continues, “how fragile the coral was: the branches themselves are the diameter of a pencil, and the reefs form into big bushes. So imagine how any heavy weight, like fishing gear, dragging through it could very easily crush it.

“At that time, in the early ‘80s, there was indication that boats were coming down from the Georgia coast and up from the Gulf of Mexico and fishing with roller trawls that were able to fish over the bottom of high-relief areas. Roller trawls have wheels that allow them to easily roll over the bottom of the ocean floor.”

These rare coral reefs, home to hundreds of species, including commercially important fish, were being destroyed. Because of their slow growth rates, it will take hundreds of years to restore them, if they can be restored at all. “My main concern is that while on paper this has been a protected area since 1984, they’ve still been heavily fished,” both by poachers and by the unaware. “Tremendous damage can be done by an errant shrimp trawler going across one of these coral reefs. One pass can destroy a great many Oculina corals.”

Inner-space trek

Many small fish swim near a head of living Oculina coral.

Figure 3: Oculina coral head surrounded by several fish. Photo credit: NURP/UNCW

During the spring Oculina expedition, aboard the NASA’s 176-foot ships Liberty Star and Freedom Star, Reed was among a team of scientists, support personnel, and media types who looked on as a camera mounted to a remotely operated vehicle (ROV) documented in real-time the contours and conditions of the ocean floor. The view afforded was a spectacular one – an inner space every bit as exotic as images transmitted by NASA from the surface of Mars. The Oculina reefs are home to many fish species, such as red grouper, scamp, tattlers, yellowtail reef fish, bigeyes, rough-tongue bass, amberjack and many more, including some species that are of considerable economic importance to the South Atlantic fishing industry (Figure 3). These fish species rely on the health of the Oculina, and their association with deep-sea coral has been long confirmed. For example: Oculina reefs have traditionally been home to grouper spawning aggregations.

Primary among the objectives of the 2003 expedition were to understand changes in the Oculina HAPC coral and fish populations over the past twenty years and to establish a monitoring baseline for future comparisons.

Evidence of coral destruction was at times overwhelming – once rich thickets, rendered rubble, no fish in view; subterraneous ghost towns (Figures 4 and 5).

Telltale scars on the ocean floor from illegal shrimp and scallop dragging are visible in this photo taken by a submersible.

Figure 4: In 2001, seven years after the area was closed to fishing, submersible studies showed that rock shrimp and scallop dragging was continuing illegally in the closed area. Photo credit: L. Horn, NURP/UNCW

A layer of broken dead coral rubble remains on the ocean floor many years after trawling.

Figure 5: Coral rubble is the likely result of fishing gear trawling through Oculina coral reefs over twenty-five years ago. Photo credit: L. Horn, NURP/UNCW

However, there have been positive findings too. According to the 2003 mission summary report, “Although fish populations observed in 2001 were not directly comparable to those observed in 1995, there was a noted increase in grouper numbers and size and especially an increase in the abundance of males of gag and scamp [groupers], suggesting the possible reoccurrence of spawning aggregations of both species [within the Oculina HAPC].”

The 2003 cruise reported that, “Several live Oculina thickets within the newly expanded [Oculina] HAPC were discovered … and extensive live bottom areas (hard bottom with live benthos and fish) were documented; we found that considerable portions of [the Oculina] HAPC that appear relatively flat in the multi-beam survey chart are actually live bottom.”

Increasing Awareness

In June of 2003 – after hearing testimony in a public forum, during which more than a few local fishers spoke of the long-term benefits of protecting the deep-sea coral, and, consequently, the fish that rely upon the coral – the South Atlantic Fishery Management Council voted to indefinitely extend the fishing restrictions within the Oculina HAPC.

Support from the fishing industry is certainly an encouraging sign. Fishers, managers and scientists together led the charge to extend the Oculina HAPC closure after 2004. As John Reed points out, protected areas mean little without public awareness. More maps indicating the boundaries of the Oculina HAPC would certainly help, as will a further understanding of the importance of these reefs as habitat for important commercial fish species.

Oculina, says Reed, “are like the redwood forests. These reefs are thousands of years old. And there are no others like them in the world.” This alone should make them worth saving and restoring for future generations.

For more information on recent research concucted on Oculina, see:

Oculina 2002 Mission
Oculina 2003 Mission

 

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Updated: September 7, 2004