Genoa's fish isolation facility. - FWS photo

A new unwanted visitor is staking claim to the Great Lakes watershed and St. Lawrence River system, leaving numbers of dead and dying fish in its wake. 

Viral Hemorrhagic Septicimia (VHS), a viral fish disease normally associated with Pacific salmon in the northwest and Atlantic cod and other species of the Atlantic Ocean, surfaced in the Great Lakes watershed in 2005, infecting a large number of species previously not known to have been susceptible to the virus. 

Numbers of economically important species of fish have been found to be at risk, including the walleye, yellow perch, and bass species.  Due to the threat of VHS entering existing aquaculture facilities and impacting captive fish populations, the United States Department of Agriculture’s (USDA) Animal Plant Health Inspection Service division (APHIS) issued an emergency order on October 24^th halting the movement of all fish species listed as susceptible from the Great Lakes states of Minnesota, Wisconsin, Michigan, Illinois, Indiana, Ohio, New York, and Pennsylvania. 

This emergency order is in place until proper and safe methods of safeguarding captive populations of aquatic animals are determined, and to prevent out of basin transfer of this pest.  The initial emergency order severely impacts Genoa’s Endangered mussel recovery program, which transfers fish species listed as susceptible to VHS to states such as Iowa, Minnesota, Wisconsin and Illinois that have mussel larvae attached to their gills. 

These mussels will drop off after a period of maturing, leaving the fish behind in its new home.  Even though Genoa’s fish originate from the Upper Mississippi River watershed, the order is based on state geographic boundaries, leading to a shutdown. 

The hatchery has been involved in mussel recovery since 2000, with millions of Endangered Higgins Eye Pearlymussel and Winged Mapleaf Mussel juveniles being released.  After consultation with many state conservation agencies and other impacted parties, APHIS amended its initial ruling on November 14^th, allowing for fish transfer to proceed, as long as adequate fish health sampling had occurred. 

The hatchery is working with the LaCrosse Fish Health Center to ensure that all hatchery fish populations are tested so that spring river broodstock collections and mussel work can proceed. 

Another aspect of the VHS threat has also been raised.  Genoa is also being impacted in its Great Lakes restoration activities.  The station currently operates an isolation building which isolates hatchery fish populations from wild eggs and resulting fish, for the purposes of bolstering the genetic potential of captive broodstocks. 

These fish are brought in and tested on 3 different inspection periods before clearing them to be assimilated into captive broodstock populations.  This ensures that no disease such as VHS enters the hatchery and causes fish losses.  In the past, coldwater species were isolated only from coldwater species, with the resulting effluent entering the ponds where warmwater species of fish are raised. 

Due to VHS’s infectivity to many species, plans to update Genoa’s isolation facility to a quarantine facility with disinfected hatchery effluent are commencing.