The GLSC has a long history of significant contributions to the understanding of aquatic resources in the Great Lakes, through partnerships and interactions with state, tribal, and U.S. and Canadian federal agencies. The main focus of the Center’s fish population research is on the long-term dynamics of native and non-native aquatic species and the sustainability of Great Lakes fisheries. Fish community structure has changed substantially in the Great Lakes since the Center was established. Species extinctions and establishment of invasive and non-native species including sea lamprey, alewife, rainbow smelt, ruffe, gobies have occurred in each lake. Because of changes in fish community structure over the last few decades, Center scientists study whether fish communities based on non-native species (such as alewife and rainbow smelt) are capable of sustaining both angling and commercial fisheries for top predators in all five Great Lakes. Even if these fisheries are sustainable, it is necessary to understand how food chains supported by non-native species compare to that of fisheries that are supported by native prey species such as the several species of deepwater ciscoes that once existed in most of the Great Lakes. Research is also undertaken to identify the factors impeding progress towards restoration of native species, including studies on fish behavior, habitat, recruitment, survival, and population genetics. The Center is recognized for its work on issues affecting the entire aquatic ecosystem in the Great Lakes basin including lake trout restoration, sea lamprey control, and annual fish stock assessments that provide timely information directly to our state and tribal partners who are responsible for managing the fisheries. In addition, the unique communities and local disturbances (i.e., habitat alterations) associated with each lake provide opportunities to study ecological processes in a comparative manner. Data sets describing the abundance of both predator and prey fish species in each lake encompass several decades and are among the most highly valued data sources in the Basin for understanding the long-term dynamics of the fish community in relation to biotic and abiotic influences, and for modeling Great Lakes ecosystem dynamics.

Fish community dynamics investigations are aided by the ability to perform genetic analyses to identify population substructure and patterns of gene flow. Both protein electrophoretic and DNA recombinant technology are used at the Center to investigate spatial and temporal genetic relationships within and among Great Lakes fish populations. Center scientists are also using genetics to survey endangered fish species and to provide historical population genetic information about extinct fish populations and species. Center scientists are currently focusing on the use of non-lethal tissue extraction techniques for these analyses.

The Center has had a long and distinguished history of conducting physiological, toxicological, and analytical chemistry studies to determine the effects of environmental contaminants on aquatic biota. In addition to contaminants, it is currently recognized that exotic species, physical habitat changes, and other biogeochemical factors influence the health of aquatic biota in the Great Lakes. Scientists have also been conducting biological monitoring of lake trout egg hatchability for several years by collecting wild eggs and monitoring their health as they develop and hatch. Center researchers are concurrently exploring and refining likely methodologies for quick and accurate estimation of chemical environmental behavior, hazard, and fate based on the chemical’s structure. An evolving database of compounds, their measured properties, and theoretical parameters is the basis for predictive software. Application of risk assessment to evaluate progress toward setting and meeting target conditions of contaminant decline and improvement in species diversity, habitat, and food provides managers with a scientific basis for making decisions concerning the health and sustainability of fish populations.

Trophic level studies in the Great Lakes encompass a wide variety of organisms from invertebrates to fish and birds. Field studies of Great Lakes organisms often lead to laboratory studies designed to provide information under controlled conditions. For example, feeding preferences of predators and competition within a trophic level can be determined by combinations of field and laboratory studies. Specialized tanks and video monitoring equipment are used to examine competitive interactions of native and exotic fish species. Center scientists are experienced in rearing, holding, and experimenting with coldwater exotic and native species. The Center maintains facilities to quarantine exotic species such as the Eurasian ruffe, which can then be used to study competition with desirable endemic species such as yellow perch.

The Center maintains equipment for collecting and identifying most of the invertebrates and fish found in the Great Lakes. Diet studies conducted at the GLSC aid in determining preferences of predators and competition within a trophic level for different assemblages of fish. A variety of technical capabilities including GIS, acoustics, and side-scan sonar allow researchers to study the interplay of fish diet and habitat and provide a link between fish population dynamics and trophic studies.

Research to determine the ecological role of native species within and between different trophic levels in the Great Lakes help determine which species are vulnerable to replacement or depletion. Researchers evaluate natural and human-induced factors including climate, land-use patterns, management practices, habitat, contaminants, and invasive species that can cause changes in the abundance of Great Lakes species. In conjunction with these studies, measures of biodiversity applicable to Great Lakes assemblages are being developed to identify specific locations and species that should be prioritized for protection. Biodiversity studies also contribute to development of rehabilitation strategies for species and their habitats. The structure and dynamics of fish assemblages can be used to infer the status of aquatic ecosystem health. Several useful measures of ecosystem health based on structure (richness, diversity, non-native species) and productivity have been identified. Measures of community stability need to be identified to further assist in understanding persistence of aquatic assemblages. Some management actions affect the diversity and sustainability of aquatic species; models relying on predator-prey dynamics to demonstrate these effects can be used to evaluate alternative management strategies in the Great Lakes basin.

To date, over 140 exotic aquatic species have been documented in the Great Lakes. In addition, Center scientists working at Indiana Dunes National Lakeshore have identified over 325 non-native species in a flora of 1460 species. Establishment of exotic species has had substantial effects in open lakes (e.g., alewife and rainbow smelt), wetlands, (e.g., reed canary grass and purple loosestrife), terrestrial systems (e.g., garlic mustard and Asiatic bush honeysuckle), and nearshore waters (e.g., zebra mussels and ruffe). Research to identify impacts of invasive species in systems of the Great Lakes basin provides opportunities to study the links between species diversity and aquatic ecosystem stability. The introduction and colonization of invasive species may affect genetic diversity (through genetic bottlenecks or hybridization) of native species, which in turn may play a role in maintaining the overall health and persistence of native populations. Understanding habitat requirements and adaptive ecology of invaders may also shed light on the types of organisms most likely to invade and colonize particular systems. Knowledge about potential invasive species may help in the control and prevention of these species and increase our management capability of habitats. A combination of field, laboratory and modeling studies are conducted to provide information pertinent to prevention, containment, and control of exotic species. Some research efforts have been dedicated to determining the ecology, distribution, life history, and reproductive behavior of exotic species.

Perhaps the best known example of the Center’s work on exotic species has been its longterm work on the sea lamprey. Research at the Hammond Bay Biological Station focuses on the effects of sea lampreys on Great Lakes fishes. Specific areas of research include alternate control techniques, application of lampricides, life history studies, population assessment, and interactions between fish and sea lampreys. Research activities on sea lamprey biology and impacts are supported through the Great Lakes Fishery Commission.

The Indiana Dunes, where Henry Cowles of the University of Chicago formulated his theory of ecological succession in the 1890’s, is often recognized as the birthplace of the modern science of ecology. Today Center scientists, some working at the very site of Cowles pioneering investigations, continue along his line of inquiry with examinations of how anthropogenic and non-anthropogenic disturbances affect native terrestrial ecosystems. Investigations by Center staff are informed by the great changes in the context of native ecosystems that have occurred since Cowles’ time. Linkages among changing lake levels, climate, and terrestrial vegetation communities are investigated. Patterns of exotic plant invasion into the Great Lake’s national parks, and how these invasions displace native communities, are documented. The effects of loss of historic disturbance patterns, such as changes in fire regimes, are examined.

The species-rich savanna and prairie habitats that once dominated the western reaches of the Great Lakes region have faired especially poorly over the past 150 years. Restoration of even remnant areas is important if this native habitat is to remain on the landscape. Center scientists are actively involved in studies to improve the restoration toolkit by examining how fire frequency and timing affect animal and plant populations, by studying how the heterogeneous light environments of savannas influence abundance of plants and animals, and by development of models to assist managers in setting restoration goals.

Embayments, wetlands, river mouths, beaches, moraines, and coastal dunes are found along 7,500 km of shoreline of the Great Lakes and inland aquatic habitats managed by the U.S. Fish and Wildlife Service and National Park Service. There are 1,150 km of connecting channels in the lakes proper (the St. Marys, St. Clair, Detroit, Niagara and St. Lawrence rivers), and over 1,300 distinct coastal wetlands (total area of 1,200 km2) along the shores of the Great Lakes and connecting channels in the United States. Because of the desirability of coastal habitats for residential, industrial, and recreational uses, these areas have been highly susceptible to human-induced perturbations, such as habitat modification, contamination, and water-level regulation. Field and laboratory research is conducted to determine the effectiveness of restoration programs in altered habitats (e.g., diked and dredged), identify rare species (e.g., ciscoes and native clams), investigate the causes of frequent beach closures due to bacterial contamination that plague beaches throughout the region (and, indeed, throughout the country), determine environmental factors that correlate with survival of species (e.g., contaminants and climate change) and develop means of enhancing and protectiing habitats for rare species (e.g., Karner blue butterfly). One goal is to understand how perturbations, such as shoreline development, vessel traffic, or changes in rates of sand deposition, affect nearshore habitats with a goal of developing restoration techniques to remediate these impairments. Center scientists also work to better document linkages, such as nutrient exchange, between nearshore habitats and lakes.

The Great Lakes Science Center headquarters is located on the North Campus of the University of Michigan in Ann Arbor where one half of its 100 staff members are located. In addition, the Center has four biological stations, one vessel base, and three vessel base-biological station combinations dispersed throughout the Great Lakes basin. Strategic placement of the Science Center’s field operations facilitates research conducted over this large geographic area. Biological stations are located at: Munising, Michigan (Munising Biological Station); Millersburg, Michigan (Hammond Bay Biological Station); Porter, Indiana (Lake Michigan Ecological Research Station); and Cortland, New York (Tunison Laboratory of Aquatic Science). A mid-basin vessel base is located at Cheboygan, Michigan. Combined biological stations and vessel bases are located at: Ashland, Wisconsin (Lake Superior Biological Station); Sandusky, Ohio (Lake Erie Biological Station); and Oswego, New York (Lake Ontario Biological Station).

The Center operates five large research vessels in the Great Lakes: the R/V Kiyi (stationed at the Lake Superior Biological Station), the R/V Sturgeon, and Grayling (stationed at the Cheboygan Vessel Base), the R/V Musky II (stationed at the Lake Erie Biological Station), and the R/V Kaho (stationed at the Lake Ontario Biological Station). The vessels, which range in length from 45 to 107 feet, are equipped with wet laboratories, trawls, gillnets, larval fish tow nets, equipment for limnological and contaminant sampling, acoustic fish-detection systems, and computers. All vessels also have state-of-the-art navigation systems for the precise location of sampling stations. The Center is the only organization in the United States and Canada that has a research vessel on each of the Great Lakes. This makes the Center unique in its ability to conduct comparative offshore field studies on fish population dynamics and related limnological and habitat research topics.

The R/V Kiyi (built in 1999; 107 ft. long) is dedicated primarily to research on Lake Superior. The R/V Grayling (1977; 75 ft.) is dedicated to research on lakes Huron, Michigan, and Superior as is the R/V Sturgeon (1975; 107 ft.). As the Center’s largest vessels, the R/Vs Grayling, Sturgeon, and Kiyi are the most versatile and are equipped to conduct a wide range of limnological, habitat, and fisheries studies including specialized equipment for conducting acoustic fish sampling. The R/V Musky II (1960; 45 ft. long) is the smallest vessel in the Great Lakes fleet and conducts research on Lake Erie. It is used for fisheries, limnological, and habitat research studies. The R/V Kaho (1961: 65ft.) is the primary research vessel on Lake Ontario that conducts fish, limnological, and habitat studies. The recent addition of the R/V Stickleback (2002; 40 ft.) to the fleet at Ashland, Wisconsin allows for more nearshore work on Lake Superior than does the larger, deeper-draft R/V Kiyi.

The Center operates a fleet of twelve small (18-25 feet) research vessels outfitted with various types of gear such as advanced navigation systems and specialized equipment required for fishery and limnological research in inland, nearshore, and connecting waters of the Great Lakes. These small vessels facilitate a variety of aquatic sampling methods including sampling of fish for predator-prey contaminant studies, capturing of specimens for laboratory studies, sampling of bottom substrate, sampling of plankton, sampling of water quality, ground truthing aerial photographs, telemetry, and diving with SCUBA to support various research activities.

Small vessels are effective because of their size and relatively low operating costs. Small vessels have been modified to serve as electrofishing boats, shallow-water fish trawlers, gill-netters and trap-netters, substrate samplers, plankton and water samplers, and macrophyte samplers. Small vessels may be easily moved from lake to lake as well as from project to project to conduct research of short duration.

The ability to examine the ecological, physical, and spatial characteristics of plant and wildlife habitat (e.g., coastal wetlands, reefs, shoals) is enhanced by technologies that can be used on small vessels including: a Global Positioning Systems (GPS) community base station; GPS receivers; PLGR+96 receivers; and a Geographic Information System (GIS) to locate, manage data, facilitate data analyses, and increase research precision. Scientists also use side-scan sonar and a remotely operated vehicle (ROV) with video to document difficult to observe events, such as trout spawning behavior.

The Center in Ann Arbor has extensive fish rearing and holding facilities, including 200- and 600-gallon fiberglass tanks, egg incubators, and other tanks for holding fish and conducting behavioral, physiological, and toxicological studies. The facilities are supplied by two 100-gallon-per-minute wells with associated equipment that includes iron filters, deionizers, settling tanks, permanent and portable chillers, and pumps and reservoirs for conditioning water. Fish rearing and holding facilities supplied by a deep water intake from Lake Huron are also available at the Hammond Bay Biological Station (HBBS). The HBBS includes tanks and flow-through “living streams” primarily used for research on the effects of sea lamprey on Great Lakes fishes. The HBBS also has a specialized facility for sterilizing male sea lamprey for a biological control program.