The Distribution of Shark Species in Relation to Macrohabitat Features off the Coast of Georgia, USA

Shark nursery areas and essential fish habitats have been an important focus of marine fisheries research since populations have been declining over the past two decades. Many shark species utilize Georgia estuaries as seasonal habitats or temporary nursery areas. The purpose of this study was to assess the distribution of coastal shark species in relation to macrohabitat features along the coast of Georgia. The Cooperative Atlantic States Shark Pupping and Nursery (COASTSPAN) dataset for 2000-2010 was provided by the Georgia Department of Natural Resources (GA DNR) Coastal Resources Division. Locations were categorized into 5 macrohabitat feature groups based on proximity to: (1) man-made structures (e.g., piers, jetties, bridges); (2) shoreline/salt marsh; (3) mouth of tidal creeks/rivers; (4) small barrier islands; and (5) water channels/open estuary. A total of 4,020 sharks representing 11 shark species were collected from April 2000-September 2010 from 9 Georgia estuaries. Atlantic sharpnose sharks Rhizoprionodon terraenovae (n=1982), bonnetheads Sphyrna tiburo (n=703), sandbar sharks Carcharhinus plumbeus (n=336), and blacktip sharks Carcharhinus limbatus (n=190) were the most abundant species collected. Approximately half of the sharks were found near water channels/open estuaries: C. plumbeus (54%); S. tiburo (52%); C. limbatus (46%); and R. terraenovae (42%). The second most preferred habitat was the shoreline/salt marsh with 39% of R. terraenovae, 31% of S. tiburo, 24% of C. plumbeus, and 20% of C. limbatus. Also, the mouth of tidal creeks/rivers was the third most preferred habitat with 25% of C. limbatus and 20% of C. plumbeus collected. Most sharks inhabited areas in close proximity to water channels/open estuaries or shoreline/salt marshes indicating that these are critical macrohabitat features for the sustainability of coastal shark populations. Fisheries managers could use these results to identify habitat areas of particular concern (HAPC) and essential shark habitat (ESH).