Ray Abundance and Diversity in the Satilla Rive

Abstract

Over the past 100 years, the Satilla River has been cut several times for logging and navigational purposes. The most notable cut is Noyes Cut, located adjacent to Umbrella and Dover Creeks. Due to changes in local economic pursuits, Noyes Cut is not used except by a few local fishermen and has potentially altered water flow and salinity gradients. Ultimately, this affects habitats of animals, such as rays. The Satilla River is home to 52 different kinds of species of saltwater and freshwater fish. These include sunfish, sharks, catfish, seatrout, and tarpon (Kenakrow, 2020). Rays are found worldwide and are the most diverse of cartilaginous fish; they play a vital role in determining the health of an ecosystem by influencing/controlling where certain fish, mollusk, and crustacean populations are. Rays can indicate if an ecosystem is in distress. Four locations in the Satilla River were sampled using experimental gill nets, otter trawls, and a multi-parameter water quality probe from July 2014 through September 2019. All rays were identified by species with total length and disc width recorded to the nearest centimeter (cm). At least 3 species of rays (possibly more), which include the Atlantic Stingray, the Smooth Butterfly Ray, and the Southern Stingray, call this area home. Additionally, this five year data set will be compared to a creel survey currently being conducted on the Satilla River. We hope to make comparisons between our 2018-2019 sampling year and the 2019-2020 creel survey. Since rays are an indicator species, it may be possible to determine if they’ve been affected by Noyes Cut. Noyes Cut was originally constructed around 1910 as a way for Edward Noyes to float logs to his lumber mill business. He used this waterway until 1933 when the U.S. Army Corps seized it and deepened the cut as an inland waterway. Over several decades, channel sedimentation has gradually affected salinity gradients which ultimately altered the natural water circulation patterns within the estuary.