The Ashland National Fish & Wildlife Conservation Office (NFWCO) unveiled four components that it will propose to its partners as its new aquatic invasive species plan, exclusive of sea lamprey control, addressing high risk locations on the south shore of Lake Superior. 

These components include early detection monitoring and rapid response for new invasive fish introduced into the Duluth-Superior Harbor, Minnesota/Wisconsin; fish community monitoring of indigenous, nonindigenous, and invasive fish in three major Lake Superior embayments, where nonindigenous and invasive fish are already established, present, or potentially could exist; some early detection monitoring for zebra and quagga mussels in high risk locations; and investigation of any potential threat relating to nonindigenous and invasive species. 

These AIS activities, in general, are advocated in the Lake Superior Lakewide Management Plan, the Lake Superior Fish Community Objectives, the Ruffe Control Plan, and have undergone testing in past aquatic invasive species experiments and control operations.

The Duluth-Superior Harbor (St. Louis River Estuary) has become a single collection point for virtually every invasive fish in the Great Lakes because it gets heavy use by the maritime shipping industry.  Commercial ships arrive here with ballast water and expel the ballast into the harbor in order to take on cargos of grain or taconite (processed iron ore).  Due to its importance, complexity and size, the St. Louis River Estuary has also been identified as a “focus point” for habitat management and preservation by the Fish & Wildlife Service.  The Ashland NFWCO is anticipating implementing the fish component of an AIS early detection monitoring model being developed by the U.S. Environmental Protection Agency, Mid-Continent Ecology Division, Duluth, Minnesota.

Healthy fish communities are generally resilient to introduction of invasive fish.  Chequamegon Bay, Wisconsin, and Whitefish Bay, Michigan, are important sport and commercial fisheries for yellow perch and many other species in Lake Superior.  Prior experimentation and investigation has indicated potential impact on yellow perch by ruffe.  Ruffe and other invasive and nonindigenous fish are established in Chequamegon Bay. 

Ruffe presence has recently been detected in Whitefish Bay.  However, Huron Bay, Michigan, has been bypassed by ruffe and other resident Lake Superior invasive fish.  The Ashland NFWCO is interested in monitoring and exploring the resiliency of Huron Bay to invasive fish, and Huron Bay would also serve as an invasive free control embayment to compare with Chequamegon and Whitefish Bays.

Due to low calcium content, low temperature, and duration of ice cover, Lake Superior waters are not conducive to the establishment of zebra and quagga mussels.  However, global warming is warming Lake Superior and shortening the duration of ice cover, thus increasing the risk for establishment and spreading of these species.  The Ashland NFWCO proposes to initiate monitoring for zebra and quagga mussels by examining vessel hulls in drydock after they have spent the open water season parked in marina slips.  Early detection of these species on vessel hulls would lead to increased monitoring activity and other potential control activities.

Rainbow smelt, a nonindigenous fish, are suspect in limiting abundance of lake herring in Lake Superior by possible predation on lake herring larvae.  The Ashland NFWCO will assist with this investigation by collecting smelt for diet analysis, when larval lake herring are available (May).

These aquatic invasive species issues are what the Ashland NFWCO envisions as important to the Lake Superior fishery.  A more detailed plan will be sent to partners for their review and comment. The Ashland NFWCO desires to implement a Lake Superior plan, exclusive of sea lamprey control, that best serves the needs of the managing jurisdictions, within the abilities of our office.