Advancing the health and well-being of animals and people


Principal Investigator: Rodman Getchell

Department of Microbiology and Immunology
Email: rgg4@cornell.edu; Phone: 607-253-3393
Sponsor: USDA NIFA-Hatch Federal Formula Funds
Grant Number: NYC-433423
Title: Is Viral Hemorrhagic Septicemia Limiting Muskellunge Abundance in the Thousand Islands?
Project Amount: $86,000
Project Period: 10/01/13-09/30/16

DESCRIPTION (Provided by Applicant): This proposal focuses on two problems: the rapid decline of one of New York's major sport fisheries, and the persistence of viral hemorrhagic septicemia (VHS) -- one of the world's most devastating viral fish diseases -- in the same watershed. The VHS problem has existed in the St. Lawrence River ecosystem for at least 8 years, where it has severely impacted the muskellunge fishery and become endemic throughout the Great Lakes. Most troublesome to the region's resource managers is the continuing presence of the virus in muskellunge prey such as round goby and yellow perch that can serve as reservoirs of infection.

Muskellunge is the top predatory fish in the Upper St. Lawrence River and an economic resource to the Thousand Islands Region as a trophy sport fish. Data from NYSDEC statewide angling survey in 2007 revealed that St. Lawrence River recreational fisheries effort was estimated at 651,000 angler days, generating average en route expenditures exceeding $10.5 million and at location expenditures of approximately $23.3 million annually--the 2nd most valuable fishery in NY State. Beginning in 2005, widespread mortality of adult muskellunge was documented and, in 2006, the invasive VHS virus was identified as the cause. Catch rate of mature muskellunge recorded in angler diary surveys has declined over 60% from pre- VHS levels. NYSDEC fishery biologists believe it is likely that adult muskellunge mortality events attributed to outbreaks of the invasive VHS virus are contributing to lower adult muskellunge numbers and reduced natural reproduction. We have previously documented the presence of VHSV in various wild fish in New York waters including Lakes Erie and Ontario, the Niagara River and St. Lawrence River, and a few inland lakes such as Skaneateles and Conesus. The most recent VHSV-induced mortality events in May of 2013, involving gizzard shad, yellow perch, and freshwater drum in Irondequoit Bay and white perch at the mouth of Chautauqua Creek on Lake Erie, demonstrates the real risk posed by the continued presence of VHSV. We propose to assess muskellunge nursery areas to determine if VHS infections are still affecting the reproductive success of this important game fish. Non-lethal samples from Upper St. Lawrence River muskellunge will be assayed with a validated, highly sensitive, quantitative RT-PCR method for VHSV. Sampling will be coordinated with Thousand Islands Biological Station (TIBS) annual surveys of spawning/nursery habitats. Prey fish species captured during TIBS surveys such as banded killifish, cyprinids, darters, yellow perch, and round gobies also will be assayed for VHSV. The controlled laboratory challenges proposed here will allow us to test the vulnerability of the St. Lawrence River muskellunge stock, as well as the virulence of any new VHSV isolates we detect. Focusing on muskellunge prey species, the potential source of infection, will provide important knowledge to the region's managers. While competition and adverse environmental conditions also may be impacting the population dynamics of St. Lawrence River muskellunge, our strategy is to first study the most likely cause for the population decline, VHSV.