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The Great Lakes Water Quality Agreement

United States Great Lakes Program Report on the Great Lakes Water Quality Agreement

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EXOTIC SPECIES

The Great Lakes sport and commercial fishing industry, valued at almost $4.5 billion annually, is at risk due to growing numbers of nonindigenous mussels and fish, such as the zebra and quagga mussels, sea lamprey, ruffe, and round goby. Populations of native fish, including lake trout, walleye, yellow perch and whitefish are threatened by the establishment of these exotic species. There is also a concern that juvenile specimens of freshwater species that are not native to the Great Lakes are still being found in the Basin, indicating that all sources of introduction have not been controlled.

Zebra mussels continue to profoundly affect the Great Lakes ecosystem. This prolific mollusk filters microscopic algae from the water column, diverting nutrients from open water to lake bottom systems, thus favoring bottom-feeding fish (and their predators) over those such as alewife and smelt (and their predators) which feed in the open water. Aquatic rooted plants (macrophytes) and their communities (e.g. large mouth bass) thrive in water cleared by zebra mussel, while habitat is reduced for species adapted for turbid waters (e.g. walleye). Zebra mussels, accidentally transported by recreational boaters, are now turning up in inland waters in all eight Great Lakes States. Municipalities and larger industries in the Great Lakes each pay, on average, $360,000 per year to control zebra mussels, with documented cumulative basinwide costs of $120 million from 1989 to 1994.

Figure 19: Nearshore Biodiversity Investment Areas



 


The impact of the zebra mussel is being felt
throughout the Great Lakes Basin

For the first time in the Great Lakes, quantitative data were collected on bottom dwelling protozoa and on the effects of zebra mussels on their populations and on nutrient transport at the sediment-water interface. In regions where zebra mussels were present, common algivorous species of microbenthos were replaced by opportunistic omnivorous and bacterivourous species. In general, community abundances tended to increase at zebra mussel sites, but the diversity within those communities decreased. This study was undertaken by NOAA's Great Lakes Environmental Research Laboratory (GLERL).

The ruffe, a spiny fish with minimal food value, continues to pose a major threat to the Great Lakes ecosystem. Native species such as troutperch have trouble competing with the prolific ruffe. Introduced to Duluth Harbor in the early 1980s, the ruffe has spread much more gradually than the zebra mussel. In western Lake Superior the ruffe has become the predominant fish species in bays and estuaries. Ruffe have now extended its range from Lake Superior to northern Lake Huron and pose a threat to native species, especially yellow perch.

The latest fish invader, the round goby, was found in the St. Clair River in 1990 and has already spread to lakes Erie, Huron, Michigan, and Superior. To date, only Lake Ontario has not reported any goby sitings, nor have they yet been documented outside of the Great Lakes Basin. Efforts are underway to prevent their spread to the Mississippi River system via the I&M Ship Canal in Illinois. A $250,000 congressional add-on will be used to construct an electronic barrier to their passage through the Canal.

Figure 20: Effects of Zebra Mussel on Phytoplankton in Lake Erie




The ruffe (top) and the round goby, recent invaders
to the Great Lakes, are impacting the ecosystem

Successful management of the last remaining uncontrolled population of Great Lakes sea lamprey -- that of the St. Marys River -- is within reach of the binational Great Lakes Fishery Commission (GLFC) and its agents and cooperators. Control strategies should reduce sea lamprey populations in Lake Huron and northern Lake Michigan by at least 85 percent. Such a reduction will allow for the resumption of lake trout stocking in Lake Huron and for the implementation of other fishery rehabilitation efforts. Trapping, release of sterile males, and a new bottom formulation of lampricide for targeting larval hot spots are tools that, applied in an optimal mix, can effect a significant level of cost-effective, environmentally sensitive control.

Once established, exotic species cannot be eradicated. Nor is there any practical means to control their eventual spread throughout the Great Lakes ecosystem and the continent. Therefore, the primary imperative is to prevent new invasions of the continent. The primary vector for unintentional intercontinental invasions of aquatic exotics, or aquatic nuisance species (ANS), is ballast water in ships. Controls on ballast water present a technically feasible opportunity for protecting the continent from new invasions. Other vectors, such as intentional fish stocking, aquaculture, and ornamental plant nurseries also need to be better understood and controlled.

The problem of exotics in ballast water has risen to attention in the United Nations International Maritime Organization (IMO) as a serious environmental issue and has now received attention from a number of the maritime nations. The maritime nations taking the lead are Australia, Canada, and the U.S. The Great Lakes regime established under the U.S. Nonindigenous Aquatic Nuisance Prevention and Control Act of 1990 (which took effect in 1993) is as yet the only general, mandatory control regime which is based on research and guidelines previously developed by Canada and Australia. Amendments to the 1990 U.S. legislation, in the form of the National Invasive Species Act of 1996 (NISA), provide for nationwide guidelines which may be followed later by mandatory controls.

The 1990 legislation also provided for the creation of a national ANS Task Force including all the responsible Federal agencies (NOAA, FWS, the U.S. Coast Guard [USCG], EPA, COE, etc.) and a regional ANS Panel supported by the Great Lakes Commission (GLC), which includes regional representatives of the Federal agencies, representatives of the Great Lakes States, representatives of commercial and public non-governmental organizations, and observers from binational and Canadian agencies. The GLC ANS Panel has played an essential role in coordinating regional work and setting the agenda for the National ANS Task Force. The GLC ANS Panel has addressed control of introduced species such as the zebra mussel and the ruffe, coordination of research on all exotics, development of educational materials and policy structures, and support for the effort to prevent new invasions.


Sea lamprey predation

Lampricide is applied to spawning areas to help control sea lamprey populations

The existing Great Lakes regime depends on open ocean exchange as the primary (virtually exclusive) means of controlling new invasions in ballast water, and open ocean exchange is the only measure currently being recommended in the non-mandatory guidelines being promulgated by IMO, the U.S., Canada, Australia, and other nations. However, it is now widely recognized that ballast exchange is not safe or practical for a significant number of ships without some alteration of tanks or piping systems. Therefore, it is imperative to develop improvements in the design of ballast systems allowing for either improved exchange or treatment of the water.

The most recent and authoritative review of potential ballast water control options conducted by the U.S. National Research Council Marine Board indicated that four options should be given priority consideration: 1) filtering; 2) nonoxidizing biocides; 3) heat; and 4) retrofitting or redesign of ballast systems to allow safe and effective exchange. These approaches are addressed in a "Binational Ballast Water Research Strategy and Plan" laid out in the 1996-1997 Binational Report on Protection of Great Lakes Water Quality submitted by Canada's Department of Fisheries and Oceans, Transport Canada Marine Safety, and the USCG in October 1997. This report (and the extensive appendices on the subject of exotics in ballast water) reviews all the current work on the subject, including the $1 million Great Lakes Ballast Demonstration Project on filtering funded by the Great Lakes Protection Fund with the support of the Council of Great Lakes Governors, the studies of chemical controls conducted by both the Michigan Office of the Great Lakes and Canadian agencies, and other work being conducted in Canada, the United States, and around the world. Most importantly, the binational report presents a clearly focused plan, supported by both the Canadian and U.S. agencies responsible for regulating ballast water, for conducting the additional work which needs to be done to raise the level of protection for the Great Lakes watershed and the North American continent in the near future.

The States of Michigan and Ohio announced the completion and submission of a Nonindigenous Aquatic Nuisance Species State Management Plan to a National Task Force in fulfillment of the requirements of NISA. The plans emphasize prevention as the key for long-term protection of State waters from harmful invaders such as the zebra mussel, Eurasian ruffe, gobies, and many others.

GLERL's long-term research monitoring program in Lake Michigan was expanded to examine the impacts of nonindigenous species. A new nearshore monitoring program was added to the existing Lake Michigan monitoring program in order to more thoroughly study ecosystem trends in central Lake Michigan. In addition, the results from a three year study designed to compare the structure and productivity of the lower food webs across the Great Lakes documented unprecedented changes in the lower food web of Lakes Ontario and Erie. Nutrient concentrations in the lower lakes are approaching those in the upper lakes and the biological community appears to be in transition, as present communities are very different from those previously documented.

GLERL's nonindigenous species program continued to assess the ecosystem in Saginaw Bay, and GLERL now has seven consecutive years of ecosystem measurements from the system, covering the period before, during, and after the peak invasion of zebra mussels. Data through 1995 reveal that abundances and biomass have not changed since 1993. This may indicate that the population has stabilized and assumed an "equilibrium" with the surrounding environment. A particular emphasis of GLERL's nonindigenous species research from 1995 to 1997 has been examining the role of the zebra mussel in promoting nuisance blooms of the potentially toxic blue-green algae Microcystis on Saginaw Bay and the effects of these blooms on the ecosystem and the mussels themselves. Microcystis blooms have also been recently experienced in Lake Michigan and Lake Erie. These blooms are associated with taste and odor problems in drinking water.

Fish and Wildlife Communities

In comparison with two centuries ago, the populations of many native fish species are greatly reduced. Their depletion can be attributed to food chain disruptions, habitat loss and degradation, over-fishing, and exotic species, among other factors. Damage to once abundant native fish populations has been profound. Non-native alewife and smelt have replaced lake herring and bloater chub as the predominant forage fish since the late 1960s and 1970s. Sturgeon survive today in much depleted numbers, although a significant recovery may be occurring in the upper Niagara River where for the first time in many decades, several year classes, including young-of-the-year, have been found. The following variety of important actions are examples of the many steps being taken to aid in the recovery of Basin populations of native species.

The landmark Joint Strategic Plan for the Management of Great Lakes Fisheries, the plan under which the Great Lakes fishery is collectively managed as an ecosystem, was endorsed by those Federal, Tribal, Provincial, and State agencies with fishery management authority on the Great Lakes. This latest edition of the Plan expands the commitment that fisheries managers have made to work together to influence all management activities which affect fish and to create stronger links to coordinate fishery management objectives with environmental objectives. LaMPs and RAPs are identified as processes in which fishery management agencies can work more effectively with their environmental counterparts. The Plan also identifies the five Lake Committees of the Great Lakes Fishery Commission as the major action arms for the agencies to achieve their joint objectives for sustaining and enhancing the fishery.

FWS took a lead role in coordinating a binational, multi-basin, interagency effort to better understand the current status and trends of lake sturgeon in the Lake Huron, Lake St. Clair, and the western Lake Erie region. Studies to define seasonal movement, relative abundance, life history, and habitat selection within this region are continuing to be conducted by this interagency workgroup. Efforts such as these to establish baseline information will be critical to efforts to restore the lake sturgeon at this and other "hot spots" on the U.S. side of the Great Lakes, including Lake Superior, Green Bay, and the Niagara River.

FWS continued to assess progress in lake trout restoration efforts in Lake Huron. This included conducting spring and fall assessments at the Six Fathom Bank Refuge, through a collaborative effort between FWS and the USGS's Great Lakes Science Center.

Recent data indicates that the structure of Lake Ontario's offshore fish community is changing in response to improved environmental conditions, and that the direction of that change is towards a fish community that more closely resembles that which existed historically. Lake trout are now showing increasing natural reproduction in Lake Ontario for the first time in 50 years. As of August 1995, the number of naturally reproduced lake trout collected during routine New York State fishery survey trawls was eight times greater than the total number collected by New York State and Ontario efforts in 1994. Wild lake trout were caught in every area of the lake in 1994, indicating that successful natural reproduction and survival in the early stages occurred lakewide from 1993 to 1994. Whitefish and burbot populations, native species that require habitat similar to that required by lake trout, have made

significant recoveries. And a recent sighting of a deepwater sculpin indicates that this formerly "extirpated" native species may be recovering. Once indigenous to Lake Ontario and its tributaries, the Atlantic salmon disappeared by 1900 due to mill dams obstructing spawning migrations, and overfishing, as well as deforestation and pollution. The FWS is participating in the investigation of the feasibility of restoring Atlantic salmon populations in historic spawning tributaries that flow into Lake Ontario and in the upper St. Lawrence River.

Studies on the population dynamics of burrowing mayflies conducted by the Pennsylvania Department of Environmental Protection (PADEP), the Biological Resources Division of the USGS, Heidelberg College, the Ohio State University, and Penn State University have indicated that the mayfly populations in western Lake Erie and the Presque Isle Bay AoC are presently experiencing exponential growth. Based on population models, the mayfly population is predicted to attain full recovery by the year 2002. Mayflies were virtually eliminated from the western basin of Lake Erie by 1960, but recolonization began during the 1990s and spread throughout most of the lake by 1996. The recovery of the mayfly augers well for the yellow perch population which is expected to grow as the density of mayfly nymphs continues to rise in western Lake Erie. The re-emergence of the mayfly is seen as a prime indicator of improved water and sediment quality in Lake Erie.

Lake trout were, historically, the sole coldwater predatory fish species in Lake Erie. However, human-induced stresses resulted in the decline or disappearance of many of the highly valued native species, including lake trout. In recent years, large amounts of resources have been expended to clean up and rehabilitate this ecosystem. As nutrient loadings, the depletion of dissolved oxygen, contaminant levels and sea lamprey-induced fish mortalities have declined, the lake's environmental quality has improved which has contributed to the recovery of several native fish species, including lake whitefish, burbot, and a worldclass walleye fishery as well as increased sightings of sturgeon. The stocking of lake trout in the lake has resulted in the successful production of a broodstock that is now producing and depositing eggs in the lake, though successful hatching in the lake has not yet been documented.

For Lake Michigan, the LaMP Program and the Lake Michigan Committee (LMC) of the Great Lakes Fishery Commission are planning to work in close cooperation. The LMC has perhaps the best fish community objectives of any of the Great Lakes which will help the LaMP set ecosystem objectives for Lake Michigan.

In 1997, FWS initiated a three year project to survey all colonial waterbird nesting sites in the U.S. portion of the Great Lakes. This was last done in the late 1980s. The present survey will allow the FWS to determine changes in the numbers and distribution of gulls, terns, double-crested cormorants, herons, and egrets. This information will be useful in developing conservation strategies for these species, which include declining (terns) as well as super-abundant (gulls and cormorants) species.


The reintroduction of the Atlantic salmon
is being studied in the Lake Ontario basin

Walleye caught in the western basin of Lake Erie

The common tern has declined dramatically in the Great Lakes in recent years. Primary causes include predation, competition for nest sites from ring-billed gulls, habitat loss, and human disturbance. FWS funded a project that is reviewing all available scientific information about their biology and population status in the Great Lakes. In addition, a field survey of all common tern colonies in the U.S. portion of the Great Lakes was conducted in 1997 and a three year study was funded to determine factors limiting common tern nesting success in Saginaw Bay. FWS also provided support to MDNR to restore critical habitat for terns at Lime Island, Michigan, one of the largest colonies in the Great Lakes. These efforts will allow the FWS to formulate conservation strategies that ensure the future well-being of this species.

Success continues for one of the oldest interagency, cooperative endangered species recovery programs in the nation. The recent increase in numbers of the Kirtland's warbler is a result of extensive habitat management by MDNR, the USFS, and FWS. These agencies have worked in partnership with a variety of public and private groups to promote education and support for the Kirtland's warbler recovery program.

A major North American Waterfowl Management Plan project is underway in northwestern Indiana. The Southern Lake Michigan Project is unique in that its purpose is to acquire, protect, and restore natural areas in the southern Lake Michigan watershed. This project is focusing more on the protection of the globally significant biodiversity of the Indiana Dunes, such as habitats supporting the endangered Karner blue butterfly, and rare types of prairies, rather than on restoration of drained wetlands for waterfowl.

The State of Wisconsin and the Bad River Tribe completed a project to reintroduce trumpeter swans into Lake Superior's Kakagon Sloughs on the Bad River Indian Reservation. 

 


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