Tag Archives: sapelo

Marine scientists map fish habitats

by Alan Flurry

Beyond the barrier islands of coastal Georgia, the continental shelf extends gradually eastward for almost 80 miles to the Gulf Stream. This broad, sandy shelf largely does not provide the firm foundation needed for the development of reef communities to support recreational and commercial fish species including grouper, snapper, black sea bass and amberjack.

“Natural and artificial reef habitats are important to Georgia fisheries because they provide hard, permanent structure on the Georgia shelf, which is dominantly a vast underwater desert of shifting sands,” said Clark Alexander, professor and director of the University of Georgia Skidaway Institute of Oceanography. “The Georgia Department of Natural Resources has invested significantly over the past several years in developing the capacity to map these areas to enhance the management of these reef communities.“

To increase the availability of high-quality hard bottom areas off Georgia, the DNR began an artificial reef-building program in 1971 to deploy materials at various locations across the continental shelf, from 2 to 30 miles offshore. Reef materials include concrete slabs and culverts from road, bridge and building demolition, subway cars, ships, barges, and U.S. Army tanks. Because some of these reefs are far offshore and DNR resources are limited, the status of some of that material has not been examined for decades.

Ossabaw sound 650p sq

A bathymetric survey of Ossabaw Sound.

For the past five years, Alexander has been leading an effort to improve understanding of marine, coastal and estuarine habitats and functions using high-resolution sonar to map state water bottoms, with funding from the DNR Coastal Incentive Grant program. Alexander’s team has amassed critical depth and habitat information for five of Georgia’s sounds (Wassaw, Ossabaw, St. Catherine’s, Doboy and Sapelo), revealing deeply scoured areas where underwater cliffs have formed to create hard substrate where complex ecosystems and biological communities have developed.

“These inshore, hardbottom habitats should enhance biodiversity in the areas near these structures and enhance ecosystems supporting both commercial and recreational species across the continental shelf,” Alexander said.

Alexander is currently leading a new, three-year project mapping important fish habitats in state waters — the newly discovered estuarine habitats, and artificial reef structures within 10 nautical miles of shore – those areas most accessible to recreational anglers, boaters and divers. In addition, his research group is mapping previously unmapped portions of the sounds and tidal rivers deeper than 15 meters to discover the extent of these newly identified estuarine hardbottom habitats.

Skidaway Institute researchers will work with DNR to update the online “Boater’s Guide to Artificial Reefs” with accurate locations and imagery of deployed materials for these reefs. These new, more accurate artificial reef surveys will also document recent changes in the locations and integrity of placed materials and verify the low-tide water depths over all features in the artificial reefs to enhance navigational safety.

K-12 teachers learn from Rivers to Reefs

by Michelle Riley / Gray’s Reef National Marine Sanctuary

In June, Gray’s Reef National Marine Sanctuary hosted the 13th annual Rivers to Reefs Workshop for Educators in association with the University of Georgia Skidaway Institute of Oceanography, the Georgia Aquarium and Gordon State College. Cathy Sakas, chair of the Gray’s Reef National Marine Sanctuary Foundation, and Kim Morris-Zarneke, manager of education programs at Georgia Aquarium, served as the primary leaders of the workshop, with assistance from Theresa Stanley of Gordon State College.  Michelle Riley from Gray’s Reef National Marine Sanctuary served as communications lead.

Rivers to Reefs is an educational expedition for teachers, focused on Georgia’s Altamaha River watershed. During the six-day trip, 16 Georgia science teachers canoed the Oconee, Ocmulgee and Altamaha rivers into the Sapelo estuary, crawled through salt marshes, traveled to Gray’s Reef and trawled the Wilmington River. They learned and explored the connections between the watershed and the ocean.

Teachers Marilyn Kinney (foreground) and Candace Bridges collect water samples in Flat Shoals Creek. Photo: Michelle Riley

Teachers Marilyn Kinney (foreground) and Candace Bridges collect water samples in Flat Shoals Creek. Photo: Michelle Riley

The week was packed with activities that most teachers never experience, beginning with a behind-the-scenes orientation at Georgia Aquarium, and it included an offshore trip to Gray’s Reef National Marine Sanctuary aboard the first working research vessel the educators had ever seen close up, Skidaway Institute’s R/V Savannah. In between, the group explored creeks, waterfalls, rivers and estuaries, and saw an abundance of flora and fauna. They frequently stopped to collect water samples, conduct water quality tests and record environmental factors to determine the overall health of the creeks and streams that flow to the river system. As the week progressed, the teachers developed an understanding of the profound influence the waters flowing through the Altamaha River watershed have on the health of Gray’s Reef and were inspired to teach their students about environmental responsibility and ocean literacy.

Always a highlight of the workshop, the marsh crawl on Sapelo Island was a memorable experience. The group sloshed on their bellies through the thick dark mud to learn why marshes are considered some of the most important and productive habitats on Earth. The estuary that encompasses the salt marsh, where the freshwater from the Altamaha River mixes with the saltwater of the Atlantic, is one of the largest estuary systems on the Atlantic coast.

The teachers on board the Research Vessel Savannah.

The teachers on board the Research Vessel Savannah.

Waters were calm for the voyage out to Gray’s Reef National Marine Sanctuary on the R/V Savannah under the command of Capt. John Bichy, marine superintendent at UGA Skidaway Institute. With extensive assistance from the R/V Savannah crew, the teachers conducted water quality tests at three separate points in the ocean. Meanwhile, the ship’s crew pulled a trawl net through the ocean at midwater depth and brought in many interesting fish, a large pile of Georgia shrimp and a handful of sharks, including a hammerhead and a small Atlantic sharpnose shark. During the trip, the teachers were delighted when they were treated to lessons by professor Marc Frischer of Skidaway Institute on black gill in shrimp and on pelagic tunicates called doliolids. While in the sanctuary, the crew deployed an underwater camera to allow the teachers to see the reef and its sea creatures in real time, without getting wet.

On the final day of Rivers to Reefs, the teachers boarded UGA’s R/V Sea Dawg, a smaller vessel used by the UGA Marine Education Center and Aquarium, a unit of the UGA Marine Extension and Georgia Sea Grant. Capt. John “Crawfish” Crawford and Anne Lindsay, associate director for marine education, conducted a field class during the two-hour trawling voyage in the Wilmington River. The teachers recorded the catch for research purposes and ended their trip with a wrap-up by Frischer and the expedition leaders, before scattering across Georgia with great memories and a treasure trove of experiences to pass on to their students this fall.