NEAFWA 2017

AUTHORS: Michael Barber; Matthew Balazik, and Greg Garman, Rice Rivers Center, Virginia Commonwealth University

ABSTRACT: Anthropogenic threats, including vessel interactions and entrainment during dredge operations, represent documented but preventable sources of mortality to endangered Atlantic Sturgeon. The tidal James River, Virginia has been the focus of VCU's Atlantic Sturgeon program since 2011 and this research benefits from an extensive array of VEMCO acoustic telemetry receivers deployed to track in-system movements of approximately 150 tagged adult and subadult Atlantic Sturgeon (ATS). The tidal James River also supports human activities, including commercial shipping and hydraulic dredging that represent potential threats to ATS recovery. Using three separate VEMCO Positioning System (VPS) acoustic telemetry receiver arrays at different locations, temporal and spatial patterns of movement by previously-tagged ATS were documented and the data used to assess behavioral responses by adult and subadult ATS to passing vessels and dredge operations. ArcGIS software was used to analyze patterns of fish movement, as well as AIS vessel identification data, records of vessel movements compiled using camera footage, and dredge operational data provided by the Corps of Engineers, Norfolk Division. Fish distributions and directional movement were compared in the presence and absence of these threats. Preliminary analysis suggests that behavioral responses by tagged ATS to potential threats vary according to the role of each array location in the species' migration, i.e., whether individuals are using a specific habitat as a movement corridor or as a staging area where linger times, and therefore exposure to potential threats, may be relatively high, as well as the distance to, and intensity of, the potential threat. How Atlantic Sturgeon react to these threats may affect the likelihood of injury and mortality and the results of this study are expected to suggest specific measures to mitigate and reduce risk factors and the probability of negative interactions.