Summary of Current Control Measures to Slow the Spread of VHS in Ontario


Viral hemorrhagic septicemia (VHS) is a viral disease previously found in several species of freshwater and saltwater fish in Europe, Japan, and on the Pacific and Atlantic coasts of North America. The Great Lakes strain was first identified in Lake Ontario in 2005 and there have been large die-offs of fish attributed to this virus. This strain affects or is carried by multiple species of fish, including: Walleye, Yellow Perch, Muskellunge, Smallmouth Bass, Rock Bass, Chinook Salmon, White Bass, Black Crappie, Freshwater Drum, Round Goby, Gizzard Shad, Emerald Shiners, Bluntnose Minnows and Spottail Shiners.


MNR has conducted surveillance for VHS in Ontario in partnership with the Canadian Food Inspection Agency since it was first detected in Ontario waters by:

  • sampling high risk lakes
  • sampling any die-offs of fish, and,
  • conducting random sampling across Ontario  

Until 2011, the waters of Lakes Ontario, Erie, and Huron and their connecting waterways and adjacent tributaries up to the first impassable barrier for all fish species were considered positive for VHS. In 2011, VHS was detected in Lake Simcoe.


VHS does not pose a threat to human health but it does pose a threat to Ontario's fish stocks. Fish with the virus are safe to eat and handle. As a precaution, fish that appear sick, dying or dead should not be harvested.


Ontario's Response


The Ministry of Natural Resources (MNR) created a VHS Management Zone in 2007. In 2011 the MNR additionally created a Lake Simcoe Management Zone. Both the VHS Management Zone and the Lake Simcoe Management Zone are bounded by the provincial road network as shown on this map (PDF, 410 kb).  Maps of the VHS Management Zone and the Lake Simcoe Management Zone are available from MNR offices.


The purpose of the management actions (outlined below) associated with the Zones is to try slow the spread of the virus and thereby protect fish populations.




Awareness and education efforts are underway to encourage anglers to not move baitfish out of the management zones and to buy baitfish locally where they intend to fish.


Commercial Bait Operators


Through licence conditions, commercial bait operators are prohibited from moving:

  • live baitfish out of the VHS Management Zone
  • live or dead baitfish into or out of the Lake Simcoe Management Zone (this action additionally addresses the spread of invasive species to Lake Simcoe).

Additionally, commercial harvesters must maintain more detailed records of baitfish harvest if they have Bait Harvest Areas that are partially located in either the VHS Management Zone or partially located in the Lake Simcoe Management Zone.


Wild Spawn Collection – Salmon and Trout Species


Eggs from virus-positive waters may be collected if all the eggs are disinfected according to the ministry's protocol.


All other spawn collection from virus-positive waters will only be allowed if the eggs go to a facility in virus-positive waters and all fish in the facility are stocked back into virus-positive waters.


Wild Spawn Collection – Walleye


Walleye spawn may only be collected from virus-positive waters if the fish are stocked into virus-positive waters and the receiving fish culture facility is located in a virus-positive zone.

The ministry will make efforts to supply virus-free walleye eggs to partner non-profit groups.


Fish Stocking and Transfers


Any eggs, or fish cultured from eggs, collected from virus-positive waters will be allowed to be stocked outside of virus-positive waters only if the facility can be certified virus-free.