DNR Surveillance for VHS Expands in 2008
April 11, 2008
As part of Michigan's coordinated response to the threat of Viral Hemorrhagic Septicemia virus (VHSv), the deadly fish disease that's spreading across the Great Lakes, the Department of Natural Resources is increasing its monitoring efforts for the virus in 2008
"The virulence of this pathogen and its potential fisheries effects has forced all of the Great Lakes fisheries agencies to rapidly develop VHSv surveillance programs," said Gary Whelan, DNR fish production manager. "Michigan's surveillance program for inland and Great Lakes waters for VHSv began in the spring of 2007 and will continue for the foreseeable future."
VHSv is a viral pathogen discovered in the Great Lakes in 2005, when it caused a large fish kill in Lake Ontario's Bay of Quinte and was found to cause multiple large fish kills in Lake Ontario and Lakes Erie, St. Clair and Huron in 2006.
DNR fisheries managers believe it likely was brought here from the maritime region of Canada via ballast water from large freighters between 2000 and 2002.
The virus has been found in 25 fish species in the Great Lakes region including walleye, muskellunge, whitefish, freshwater drum, and gizzard shad.
To date, the virus has been found in only one body of inland water in Michigan.
In 2007, a total of 8,933 fish from 36 species were collected by DNR Fisheries Division personnel and tested at the Aquatic Animal Health Center lab at Michigan State University.
The majority of the fish collected were part of the planned surveillance program with a smaller numbers tested as a result of reported fish kills or symptomatic fish observed by the public or DNR staff.
The fish collections occurred at 62 different sites throughout the state -- 33 sites on the Great Lakes and 29 sites on inland waters.
The only VHSv positive fish found in inland waters in 2007 were in Budd Lake, Clare County, which was collected during a fish kill in May 2007. It could not be determined if VHSv was the primary cause of the Budd Lake fish kill or a contributing factor.
The only Great Lakes positive sample in Michigan waters was a single chinook salmon found to be positive with low virus levels during the egg take at the Swan River Weir near Rogers City, a location found to be positive in 2006.
Plans for surveillance in 2008 will include sampling 78 inland waters and 16 Great Lakes locations. A total of 13,920 fish are planned to be sampled. Additional samples also will be taken where active fish kills with VHSv signs are occurring.
All wild broodstocks (fish used for egg takes) will be sampled for VHSv including muskellunge from Lake Hudson and Thornapple Lake, steelhead from the Little Manistee River, walleye from the Muskegon and Tittabawassee rivers along with Little Bay de Noc, northern pike from Sanford Lake, chinook salmon from the Little Manistee River and Swan River weirs and coho salmon from the Platte River weir.
Standard hatchery fish health monitoring will continue to be conducted as it has for more than 20 years for VHSv and a number of other fish pathogens. VHSv has never been detected in any of the DNR hatcheries.
"Early sampling already is underway to monitor the health status of several Great Lakes walleye broodstocks and determine if VHS can be detected at colder water temperatures in a group of inland lakes.
Fish collections and testing will continue through the summer and early fall.
A grant for $137,000 was obtained from the U. S. Department of Agriculture-Animal and Plant Health Inspection Services (USDA-APHIS) earlier this year that will assist the DNR with the cost of collecting and processing these samples.
"We are very appreciative of the efforts by USDA-APHIS to provide additional funding that will allow us to intensify efforts to document the distribution of VHSv in our state," said Martha Wolgamood, Southern Lower Peninsula fish production manager.
The public is asked to continue to report any unusual fish kills to the DNR using either the e-mail link provided on the Fisheries Division Web site at www.michigan.gov/dnrfishing or directly to any DNR fisheries office.
"We are particularly interested in fish kills that are abnormal and have fish in the process of dying that have bloody patches on their skin," Whelan said. "Fisheries staff will evaluate each of these reports and will sample those that look suspect. This information is valuable to our surveillance program and helps us target waters that we not planning to sample for VHSv but may be infected."