Viral hemorrhagic septicemia and freshwater fisheries

This report summarizes the state of the science on viral hemorrhagic septicemia (VHS) and provides guidance for prioritizing future VHS research to support science-based fisheries management in Wisconsin. The VHS virus was first detected in Wisconsin in May 2007 and poses a threat to sport and commercial fisheries in the state. Herein we provide a brief background on VHS identification, classification and distribution, summaries of recent research on VHS and risk management pertaining to fish diseases, and the identification of VHS research gaps. Research recommendations based on the authors' interpretation of the state of the science of VHS as outlined in this report, and made in the context of practically supporting the fisheries management obligations of the Wisconsin Department of Natural Resources, include: 1) conducting a formal risk analysis on VHSV Type IVb, the new variant of VHS virus found in Wisconsin and the Great Lakes region, and on its potential impacts on fish populations in Wisconsin, 2) contributing to the development of rapid testing procedures for detecting VHSV when present and for declaring groups of fish free of VHSV when the virus is not present, 3) contributing to the development of VHS challenge models, particularly for commonly used baitfish species, 4) initiating a long-term monitoring study on the effects of VHSV on fish populations and fish communities in a selection of VHSV-positive waters, and 5) developing and parameterizing disease models for VHSV.