In 2004, the Huron-Erie Corridor Initiative was proposed by the U.S. Geological Survey Great Lakes Science Center (GLSC) to address high priority research issues affecting aquatic resources and environments in the Huron-Erie Corridor (HEC). The HEC includes the waters of southern Lake Huron, the St. Clair River, Lake St. Clair, the Detroit River, and western Lake Erie. Conflicting uses of the HEC waters for waste disposal, water withdrawals, shoreline development, shipping, recreation, and fishing have decreased the ecological resilience of this ecosystem. Managers need quantitative scientific information to make better-informed decisions regarding aquatic natural resources in the HEC.

The purpose of the HEC Initiative is to create relevant new science to better address the needs of fisheries and aquatic resource managers in the HEC. The Initiative is a bi-national, collaborative partnership of over twenty organizations, including government, industry, tribal, and university participants. Resource managers, scientists, and other stakeholders are using a consensus-building, multidisciplinary approach to identify research themes and priorities, develop funding strategies, and increase public involvement in the Initiative.

The Huron-Erie Corridor includes one of the busiest navigation centers in the United States and is an international trade route with Canada and overseas markets. Over $80 billion/year in trade between the U.S. and Canada is carried out across the HEC. Over 5 million people live within an hour’s drive of this Corridor. The Detroit River International Wildlife Refuge and the Ottawa National Wildlife Refuge are also located within the HEC. Habitat in these waters is used by over 60 species of spawning fish, and is home to sixteen threatened or endangered fish species. The Corridor is also part of the central Great Lakes flyway for millions of migratory waterfowl, and contains some of the largest and most diverse wetlands left in the region.

A number of factors have resulted in detrimental environmental changes in the HEC ecosystem. For example, the dredging of river bottoms for navigation has caused changes to natural flow regimes in the HEC as well as the loss of substrates required by spawning fish and benthic communities. Discharges of sewage and industrial waste into HEC waters have had negative effects on water quality with consequences to both wildlife and human health. Invasive aquatic species that entered the Lakes through shipping channels have severely altered populations of native fish and mussels. Shoreline development and changing land use have resulted in the loss or degradation of coastal habitats such as wetlands and beaches.

To address these use-conflicts effectively, we must communicate and work with scientists, managers, and other stakeholders throughout the HEC to determine present and future science needs and priorities. Partners who are already collaborating with USGS scientists in the HEC encompass a wide variety of local, state, federal, and provincial agencies, as well as non-governmental organizations and private industry. A multidisciplinary steering committee has been formed that is comprised of scientists, managers, and other stakeholders with a strong interest in the aquatic ecosystems of the HEC. An organizational meeting was held in February 2005 at which resource managers identified the scientific information they needed to better manage natural resources in the HEC. A study design framework (Gillespie et al. 2002) was used as a part of this process. The meeting clarified goals and objectives of the HEC Initiative and identified areas of needed scientific expertise.

The broad interrelated biological management-driven research themes of the HEC Initiative will include: 1) Restoration ecology of native species and their habitats, 2) Effects of aquatic invasive species on native aquatic species, and 3) Conservation biology of native species. Specifics of each theme will be determined through discussions and consensus with interested partners. Restoration of ecological resilience within the HEC is considered an overriding focus of this Initiative.

Restoration Ecology of Native Species and Their Habitats

Sixteen species of fish classified as threatened or endangered inhabit the HEC. Habitat loss and alteration of habitat are major factors that have contributed to the decline of many of these species. Native fish populations have been greatly affected by habitat alterations in the HEC. Millions of tons of cobble and gravel were removed from the St. Clair and Detroit Rivers to build the cities of Detroit and Windsor and create navigation channels (Larson 1981). These gravel substrates provide spawning and nursery habitat for walleye, lake sturgeon, darters, and other native fish species. Substrate removal has contributed to fish population declines.

Changes in water velocity and temperature have also affected native aquatic species in the HEC. Creation of a deep-draft (27 ft) shipping channel (Larson 1981) reduced water velocity over spawning substrates at 13 historic reputed fish spawning sites in the St. Clair and Detroit Rivers (Goodyear et al. 1982). Large-volume discharges of heated water from numerous industries, power plants, and municipal sewage treatment plants on both sides of the river may have affected the thermal “window” for spawning fish. Lake sturgeon, for example, spawn at water temperatures between 11-15°C. Due to the higher water temperatures, sturgeon may be spawning prior to production of suitable food resources in their nursery habitat downstream, reducing their survival and successful recruitment.

Since 1998, in collaboration with its partners, the GLSC has conducted research to gather information needed for the successful restoration of a remnant population of native lake sturgeon in the Detroit River, including stock size assessment and habitat evaluation (Hill and Manny 1999, McClain and Manny 2000, Alpena FRO 2003, MDNR 2002), spawning success and early life history (Nichols et al. 2003), extent and composition of known-active and historic-reputed spawning grounds (Manny and Kennedy 2002), sturgeon movements (Boase 2003; Caswell et al. 2004), and body burden of contaminants in lake sturgeon (Begnoche et al. 2003). One strategy being used by GLSC scientists and partners to restore lake sturgeon populations is to create spawning habitat in the Detroit River near Belle Isle to replace habitat lost from dredging. This habitat was constructed in June 2004 and will be closely monitored to assess the success of the project (Read et al. 2003).

Successful restoration/rehabilitation of native aquatic species and habitats in the HEC also requires knowledge of the hydrology of the system. For example, low velocity, vegetated habitat, important in the life history of many aquatic organisms, is largely lacking in many parts of the HEC. We will be combining the biological and hydrological components of this project through collaboration with the USGS Water Resources Discipline (WRD). The WRD can provide the expertise necessary to determine where to best focus our efforts for restoring low velocity, vegetated habitat as well as other natural flow regimes in the system.

Effects of Invasive Species on Native Aquatic Species

Non-native aquatic organisms were first discovered in the Great Lakes in the early 1800’s, with the total number of established species now estimated at 162 (Ricciardi, 2001). More than one-third of these organisms have been introduced in the past 30 years, coinciding with the opening of the St. Lawrence Seaway (GLC 1992) and resulting in both biologic and economic consequences to the Great Lakes region. The most problematic invasive species include alewife, common carp, Eurasian ruffe, quagga mussel, rainbow smelt, round goby, sea lamprey, spiny waterflea, and zebra mussel. These species alone have contributed to massive extinctions of native fauna and severe alterations of food webs in the Great Lakes. Negative effects of invasive species include competition with native species for food, habitat, and spawning sites, and predation on native species.

Invasive species have had major economic impacts in the Great Lakes region as well. For example, zebra mussels have caused millions of dollars of damage to municipal and industrial water intake pipes. Sea lamprey have greatly reduced populations of commercial and sport fishes, such as lake trout and lake whitefish, resulting in lost income for commercial and recreational fisheries. Round gobies prey on lake sturgeon eggs contributing to the decline of sturgeon populations (Nichols et al. 2003).

Great Lakes managers and resource users presently need information on all aspects of potential and existing invasive species, including basic biology, geographic distribution, and potential impact on existing biota. Working together and using a proactive research approach we will develop strategies that can help managers respond effectively to current and potential invasive species issues in the HEC.

Conservation Biology

Conserving the aquatic biological diversity of the HEC is an essential component of this Initiative. Maintaining healthy and productive aquatic ecosystems throughout the Corridor benefits the human population as well as the organisms inhabiting these waters. Over 500,000 boats are registered in Michigan and use the HEC waters for sport and commercial fishing and other recreational activities. HEC waters are also a source of drinking water and process water for industry. Changing land use, invasive species, coastline development, and many other factors have impacted native species and their habitats within the HEC. The Restoration Ecology and Invasive Species research themes already discussed interrelate well with the Conservation Biology theme because research results should ultimately contribute to the maintenance of biological diversity and ecosystem resiliency. For example, the lake sturgeon restoration discussed above facilitates the conservation biology of other species, such as native darters. In addition, the GLSC has created a land use map of the Corridor which can serve as a baseline to monitor changes in land use and predict potential ecological impacts of those changes.

Research Needs and Potential Strategies

The development of research strategies and relevant new science are key objectives of the HEC Initiative. Our partners believe that habitat restoration should be a primary research focus in the HEC. Initial research needs and priorities have been determined through discussions with the HEC Initiative steering committee. It was decided, by consensus, that initial research should focus on: 1) Compiling historic HEC habitat and data resources, 2) Current habitat function, and 3) Roadblocks to habitat restoration. A set of preliminary hypotheses are currently being developed on how historic loss of habitat and changes in ecosystem function will impact future habitat restoration efforts. Many factors may change habitat or ecosystem function. Two primary factors of importance in the HEC relate to water flow regimes and invasive species. Altered flow regimes may disrupt the linkage between fish spawning and nursery habitat by sweeping drifting fry past suitable nursery areas. Habitat function may also be lost due to altered predation pressures by invasive species such as the round goby, reducing recruitment of native fish from spawning areas.

It is essential that we use a multidisciplinary ecosystem approach as we develop these strategies. To create an effective experimental design requires scientific expertise in a number of areas including biology, hydrology, ecology, water quality, and statistical design. It is also important to work with partners that represent federal, tribal, state, provincial, and local agencies as well as non-governmental organizations, universities, and industry. All stakeholders will play a critical role in the success of this project and the HEC Initiative.

Goals and Objectives of the HEC Initiative

1) Identify key aquatic research issues in the HEC using a consensus building and adaptive management approach.
2) Develop a research strategy to address resource management issues in the HEC that are identified.
3) Create relevant new science to better address the needs of fisheries and aquatic resource managers in the HEC.
4) Provide managers with the scientific information they need to address aquatic resource issues in the HEC.