Effects of Hydraulic Dredging and Vessel Operation on Atlantic Sturgeon Behavior in a Large Coastal River

EFFECTS OF HYDRAULIC DREDGING AND VESSEL OPERATION ON ATLANTIC STURGEON BEHAVIOR IN A LARGE COASTAL RIVER Michael R. Barber, B.S. A thesis submitted in partial fulfillment of the requirements for the degree of Master of Science in Biology at Virginia Commonwealth University. Virginia Commonwealth University, 2017. Major Advisor: Dr. Greg Garman, Director of Rice Rivers Center, Center for Environmental Studies/Department of Biology The tidal James River, a focus of VCU's Atlantic Sturgeon program, supports both commercial shipping and hydraulic dredging. These anthropogenic threats present documented but preventable sources of mortality to the endangered species. Using three separate VEMCO Positioning System (VPS) receiver arrays, spatial data of previously-tagged fish were collected. ArcGIS and Programita software were used to analyze fish spatial distributions in the presence and absence of potential threats, using additional data including automatic identification system (AIS) vessel locations, vessel passages compiled using camera footage, and dredge records provided by the US Army Corps of Engineers. The data showed a change in distribution associated with vessels that varied according to river width but not vessel type. Dredging was associated with differences in spatial distribution, but more clearly for adults than sub-adults. The responses of Atlantic Sturgeon provide information necessary to propose potential threat mitigations, including seasonal restrictions for both vessels and dredging.