Shallow Octocorals of the SAB

Guide to the Shallow Water (0-200 m) Octocorals of the South Atlantic Bight.
S. T. DeVictor & S. L. Morton, 2007

Methods

The specimens examined for this work were deposited either in the National Museum of Natural History (NMNH) or the collection of the Southeastern Regional Taxonomic Center (SERTC). The majority of cataloged SERTC specimens were collected from SERTC cruises or accessioned from the College of Charleston’s Grice Marine Laboratory (GML), which holds a largely unidentified collection of octocorals from the last four decades. The species list presented in this work is limited by the restricted amount of sampling done by the NMNH, SERTC, and GML in the SAB and is not intended to be a complete distributional representation. Undoubtedly, as more collections are made in the SAB, more range extensions and new species are likely to be encountered. All SERTC specimens were examined and identified by the first author, and every attempt was made to compare them with specimens deposited in the NMNH that were identified by knowledgeable workers.

Collections of fresh specimens were made by scallop trawl, hand collection using SCUBA, or by manned submersible. Live specimens were relaxed in 32 mg/l magnesium chloride to induce tissue expansion and photographed with a Nikon Coolpix, either through a dissecting microscope or with the camera’s macro setting. Most live specimens were preserved in 95% ethanol, but occasionally specimens were fixed in 10% buffered formalin and switched to 70% ethanol for long-term storage.

Specimens were viewed under a dissecting microscope to examine gross morphology and the orientation of sclerites in the tissue. To examine sclerites individually, the coenenchyme was dissolved in household bleach (sodium hypchlorite), washed repeatedly with water, and prepared on a glass slide for viewing under a compound microscope fitted with an ocular micrometer.

To prepare specimens for scanning electron microscopy, specimen tissue was selected from specific localities on the colonies (such as polyp, coenenchyme, medulla, etc). The tissue was dissolved in bleach and the liberated sclerites were washed in distilled water and 95% ethanol. Once dried, the sclerites were hand selected using a single-bristle brush or fine forceps and placed on adhesive mounted onto aluminum SEM stubs. Samples were coated with approximately 1.5 nm of gold-platinum using a Denton Vacuum Desk II Sputter Unit. Samples were examined using a JEOL 5600LV Scanning Electron Microscope at 20 kV. Once captured, images were selected based on their representative value and quality.