Effects of salinity and sedimentation on the Gorgonian Coral, Leptogorgia virgulata (Lamarck 1815)

Construction of jetties along the Texas coast has provided hard substrate biota with suitable habitats for attachment that is otherwise scarce. Although similar to natural hard bottom environments such as coral reefs or offshore banks, jetties in temperate or subtropical areas are subjected to substantially more environmental instability including swift channelized currents, terrestrial runoff, maintenance dredging, fluctuating temperatures, and swells from ship and recreational boat traffic. The gorgonian coral Leptogorgia virgulata, found on south Texas jetties, is constantly exposed to the variable salinity and sediment loads associated with these jetty systems. In this study, L. virgulata was collected from the Aransas Pass jetties near Corpus Christi, Texas and experimentally tested to determine their ability to tolerate a range of salinities and sediment loads over 14 days. In response to salinity, L. virgulata showed significant tissue loss (p < 0.05) at 10, 15, 45, 50 and 60 with 100% loss at 60, but showed little or no tissue loss and peak polyp activity at 25–40. When exposed to sedimentation treatments up to 20,000 mg l− 1, L. virgulata maintained healthy tissue and polyp feeding activity and did not show any symptoms or significant differences in tissue loss. These results indicate that L. virgulata is well-adapted to euryhaline conditions and is very tolerant of high sediment loads, a factor in its success on structures along the Texas coast.

► Leptogorgia virgulata is very abundant along Texas coastlines.
► L. virgulata is well-adapted to euryhaline conditions.
► At high concentrations of sedimentation L. virgulata was healthy and very active.
► Many invertebrates and fish are dependent on L. virgulata as habitat.