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Scientists get fish's eye view of reef life

Of The Post and Courier Staff
Originally Published on: 08/02/02
Page: 1

See PDF for Sheils map entitled 'Deep Reef Mission'

Some 60 miles east-southeast of Charleston, marine scientist George Sedberry prepared Thursday for his next deep-sea dive and made notes about the brightly colored fish he'd watched 200 feet beneath the surface at the St. Augustine Scarp.
"We have seen many exciting things," Sedberry reported via e-mail from aboard the research vessel Seward Johnson.
The S.C. Department of Natural Resources senior scientist is principal investigator on the national Islands in the Stream 10-day exploratory voyage that departed from Fort Pierce, Fla., last Saturday.
The next day Sedberry descended in a submersible to investigate spots no human had ever seen and to learn what biologists and fishermen alike have only pondered.
On what Sedberry described as a spectacular shelf-edge reef about 200 feet down, he observed beautiful tropical fish such as queen angelfish, rock beauty, yellowtail reef fish, squirrelfish and many others.
"The diversity of fish and the bright colors of sponges, corals and other encrusting invertebrates gave the rocks a colorful glow that ranged from red to orange to lime green and purple," Sedberry said.
He hoped to find spawning sites of fish that commercial and recreational fishermen value so highly that the species are dwindling and need help.
So far, Sedberry hasn't seen that activity, but all the signs are right.
Scamp grouper sported spawning colors: A few large males wore the aggressive "gray head" phase that they display to attract and keep a small number of females around them, Sedberry said, and several smaller females were swimming alongside a large gray-head male.
He also observed smaller females beside a large male hog snapper whose color display Sedberry described as spectacular.
The dives at the St. Augustine and Jacksonville scarps could prove especially useful, because both are being considered as Marine Protected Areas. Fishing could be restricted, for instance during spawning season, if biologists knew when important fish congregated.
This week's dives also would provide baseline data, for comparison, to see whether any future protection brought an increase in snapper and grouper to the sites, Sedberry said.
"I was amazed at the beauty of the reef and the amount of rock habitat. I was troubled by the few fish seen on the reef. ... It seemed very empty in many places. Some spots did, though, have a fair number of scamp grouper, and it appeared as if they were spawning there."
Large rocks at depths of 175 to 200 feet formed a relatively narrow ribbon running south to north for at least 30 miles, at the edge of a scarp where the bottom dropped 20 to 30 feet along a rocky ledge.
"The rock pile resembles the remains of an ancient city, such as Mayan ruins or other fallen pyramids," scientists told Sedberry.
"The rocks themselves were squared-off boulders the size and shape of small refrigerators," said College of Charleston geologist Leslie Sautter. "At times they were almost perfectly aligned in a grid pattern, and one could imagine that they'd been carefully arranged on the seafloor."
Sautter says the shapes probably resulted from faulting of the limestone/sandstone rock exposures.
The next dive revealed the Jacksonville Scarp to be large, irregular rock rubble with a thin layer of sand blanketing a hard rock pavement.
Arms on the submersible gathered five large boulders, each completely covered by sponges, soft coral, bryozoa and crustaceans. "These rocks truly are the substrate on which the reef ecosystem is founded," Sautter added.
Two scientists at a time dive aboard the submersible to collect creatures and sediments and to observe and make videotapes of previously unseen activity.
Pam Cox Jutte, DNR assistant marine scientist who expects to dive on Scamp Ridge today, wanted to observe sponge and coral communities at deep reefs. "We haven't been disappointed," she said of an earlier dive. She reported abundant black coral about 4 feet tall that pop from the seafloor like coiled bed springs.
Scientists collected several species of vibrantly colored sponges, which Jutte described as undersea hotels for a host of organisms. She will study the sponges in detail in her Charleston lab and, she wrote in an e-mail, "New species of small crustaceans or worms might be discovered living within the sponges."