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May 2021

Spreading Throughout the Great Lakes Region, Exotic Invasive Spiny Water Flea Represent a ‘Clear and Present’ Danger to Michigan’s Inland Lakes

First observed in the waters of Lake Ontario in 1982, the exotic aquatic crustacean known as spiny water flea are a native of Europe and Asia that were first introduced to the freshwaters of North America via the discharge of contaminated ballast water emanating from a trans-oceanic cargo freighter that had entered the Laurentian Great Lakes through the St. Lawrence Seaway. Subsequently detected in Lake Huron in 1984, Lake Erie in 1985, Lake Michigan in 1986, and Lake Superior by 1987, spiny water flea began to appear in a steadily increasing number of inland lakes located throughout the region beginning in 1990. Large inland lakes in the region that now host abundant populations of spiny water flea include Lake George in upstate New York, Minnesota’s Lake in the Woods, the Madison Chain of Lakes located in Wisconsin, and Lake Michigamme, one of Michigan’s largest inland lakes, that is situated in the Upper Peninsula near Marquette.

Microscopic aquatic animals that are known as zooplankton, spiny water flea – scientific name Bythotrephes longimanus, are opaque in color, and are characterized by a single long tail that comprises 70% of their length that on average ranges from one-quarter inch (6 mm) to five-eighths inch (16 mm). The exotic invasive zooplankton species may also be identified by the presence of one to four barbs on their long tail, and by a head whose appearance is dominated by the presence of a large, single black eye. Capable of exponential population growth, and of rapidly establishing sustainable populations in newly invaded lakes, spiny water fleas have evolved to utilize both asexual and sexual means of reproduction. In warm summer waters, each adult spiny water flea is capable of asexually cloning up to 10 new individuals in as little as two weeks. Responding to the cooler waters of mid-to-late fall, male and female spiny water flea reproduce sexually, and produce large quantities of large, robust eggs that settle in lake sediments where they overwinter until the following spring in a dormant state. Spiny water fleas that are cloned, and/or that are hatched from eggs in response to the arrival of warm waters are capable of reaching maturity, and of reproducing within one week of the time they are born. It is important to note that part of the extraordinary ability of the exotic crustacean to successfully spread from lake-to-lake is enabled by the fact that the eggs of the species that are often eaten by minnows that are later captured by fisherman for use as bait, and then transported via trailered watercraft to a new lake are capable of surviving passage through the minnow’s gut, and of later hatching, representing the beginning of a new invasive population.

Preferring mesotrophic (moderately productive) and oligotrophic (low bio-productivity) inland lakes found in northern temperate regions of the earth, spiny water fleas regularly migrate from lower layers of the water column hosting deep, dark, dissolved oxygen starved waters to the well-lit, well oxygenated waters of the upper water column. Optimal water temperature for spiny water flea ranges from 14° – 23° C (57° – 73° F). Intolerant of water temperatures that exceed 26° C (78° F), temperature is known to play a major role in determining their sexual and asexual reproductive efficiency, and their overall abundance within in a given aquatic ecosystem. Preferring freshwater ecosystems, it is important to note that within their native geographic distribution range, spiny water flea are capable of tolerating the brackish water ecosystems that are often located near oceanic coastal areas.

The most significant ecological impact rendered by abundant populations of invasive spiny water flea are derived from the fact that the highly predatory crustacean preys heavily upon native zooplankton, including Daphnia, that represent a critical food source for native fish populations in most northern temperate inland lakes. The aggressively foraging invasive zooplankton species is capable of adversely affecting the growth and survival of young fish such as bluegill and yellow perch by reducing or eliminating native zooplankton species that form the “ground floor” of the aquatic food chain in many northern temperate inland lakes. Research indicates that spiny water fleas are responsible for consuming 1.5 to 5 times the quantity of native zooplankton than is consumed by juvenile yellow perch. This fact is particularly important in light of the fact that most native juvenile fish are incapable of preying upon the invasive zooplankton species due to their extraordinarily long, barbed tails. Abundant invasive spiny water flea populations are also capable of dramatically affecting inland lake ecosystems by reducing or eliminating native populations of native zooplankton species such as Daphnia magna, that in addition to representing an important native food source for juvenile fish, are also known to make important contributions to helping sustain clear water by aggressively foraging upon, and controlling the density of water clarity depriving single cell green algae species knows as phytoplankton.

Transported to new inland lakes by the 95% of recreational fisherman who tow their watercraft from lake-to-lake, spiny water flea attach their long barbed spines to all types of surfaces – including fishing lines, nets, and anchor ropes—and unless boats, trailers, and fishing gear are thoroughly cleaned between each trip by their owner/operators, transient watercraft are capable of carrying exotic invasive spiny water fleas and their eggs between lakes, infecting one lake after another with a highly aggressive invasive species. Due to their relatively small size, spiny water fleas are often very difficult to discern on an individual basis, and are usually detected by the presence of clusters of thousands of spiny water flea that appear as a “bristly glob of jelly with black spots” on monofilament fishing line.

The significant ecological threat posed by the highly invasive zooplankton species is emphasized by the fact that they are capable of exponential population growth, and possess the capacity to irrevocably alter the aquatic ecosystems they invade, and to ultimately diminish the recreational and economic value of affected inland lakes. Based upon their ability to severely disrupt native aquatic ecosystems, and upon the fact that lake managers currently possess no viable means of eradicating, or of even controlling the abundance of the aggressive crustacean, spiny water flea represent one of the most significant biological invaders to have thus far entered the freshwater ecosystem inundated Great Lakes region.

In the case of steadily expanding abundant populations of the exotic invasive crustacean, the only viable means of limiting the ecological impact of the rapidly reproducing species is to attempt to curtail the number of aquatic ecosystems the species successfully invades by encouraging transient fisherman and recreational boaters to thoroughly “clean, drain, and dry” their watercraft, batt wells, fishing equipment, and trailers before towing their boat to a new lake.  For more information on the Michigan Clean Boats, Clean Water program, visit .

Proposed MI Senate Legislation Would Eliminate Authority of Local Governments To Approve, and/or Regulate Sand and Gravel Mining Operations

Representing a renewal of an intensive effort that began in 2017, the Michigan Aggregates Association, in consortium with gravel and sand mine operators, and other interested business groups have launched a new push in Lansing to pass legislation that would make it much easier to open and operate a sand and gravel mine near residential communities. If passed into law, the language of Michigan Senate Bills 429, 430, and 431 would act to eliminate the authority of local governments to approve, and void the ability of local zoning officials to regulate mines in a manner that may help to  minimize their negative impact upon the quality of life for residents living in surrounding communities. The proposed legislation would also act to move approval authority for aggregate mines from local governments to the Department of Environment, Great Lakes, and Energy (EGLE). It is important to note that language embedded in the package of bills would also effectively prohibit EGLE from denying a permit application based solely upon the potential for the proposed surface mining operation to have a negative impact on the water quality of surrounding lakes, streams, wetlands, and/or of groundwater.

Those supporting the initiative, including highway construction contractors, and others currently involved in supporting a large number of projects focused on rebuilding and repairing Michigan’s highways, roads, bridges, and dams argue that their pro-active support for the legislation stems from the fact that they often have to travel relatively long distances to acquire the large quantities of gravel and sand that are required to complete their work. Supporters of the legislation have also argued that the 325 gravel and sand mines currently operating in Michigan are unevenly distributed throughout the state making it difficult for them to efficiently meet the exceptionally high demand for aggregate on a timely basis.

Those opposing the initiative that is being sponsored by the Michigan Aggregates Association, and their allies within the highway construction industry argue that the legislation would effectively eliminate zoning authority and oversight capability from local governments, and allow sand and gravel mining operations to negatively impact local residents, public schools, businesses, and hospitals. It is important to note that several non-profit organizations, including the Michigan Association of Counties, the Michigan Township Association, the Michigan Municipal League, and the Michigan Association of Planning,  and several environmental groups such as the Michigan Chapter of the Sierra Club, and the Metamora Land Preservation Alliance, for example, have joined forces to help ensure that the legislation is not passed into law. Opposition to the controversial legislation also stems from the reality that even though there is a high potential for surface mining operations to contaminate groundwater supplies, and to negatively affect the water quality of surrounding lakes, streams, and wetlands, the proposed legislation would forbid the Department of Environment, Great Lakes, and Energy from denying permit applications based solely on this fact.

Readers should “stay tuned” to future Michigan Waterfront Alliance newsletter updates for information regarding the status of the proposed legislation.

Minnesota Leads the On-Going Battle with Exotic Aquatic Invasive Plant and Animal Species

by Scott Brown, MWA Board of Directors

Pro-active Support from the Minnesota State Legislature and an Aquatic Invasive Species Surcharge on Watercraft Registrations Provide the Necessary Resources to Enable an Effective Battle Against Exotic Aquatic Invasive Species

Responding to increasingly widespread infestations of Eurasian watermilfoil, curly-leaf pondweed, starry stonewort, zebra mussels, and spiny water fleas, that are known to represent a significant public health threat, and that may also severely limit the capacity of affected aquatic ecosystems to support desirable native aquatic plant and animal species, the Minnesota state legislature has acted to establish a well-funded and intensely pro-active Minnesota’s Invasive Species Program.

Providing robust funding appropriations and enabling sustainable funding mechanisms in order to effectively administer programs that are dedicated to curbing the spread and harmful influences of aquatic invasive species, Minnesota’s state legislature seems to understand that rapidly propagating exotic aquatic invaders represent a dire threat to the current and future recreational status and economic value of their state’s vast natural legacy of high-quality inland lakes, rivers, streams, and wetlands that forms the basis of  Minnesota’s $16 billion dollar freshwater ecosystem-based tourism industry.

Minnesota’s robust Invasive Species Program includes a Department of Natural Resources (DNR) administered Aquatic Invasive Species Control Grant  that is intended to help local entities such as lake associations, watershed districts, cities, and counties fund the control of curly-leaf pondweed, Eurasian watermilfoil or flowering rush. Minnesota also administers a program entitled Aquatic Invasive Species Prevention Aid that is dedicated to preventing or limiting the spread of non-native, aquatic invasive species at the county level. Revenue provided by the program is allocated based upon each county’s share of watercraft trailer launches, and watercraft trailer parking spaces. The Minnesota Department of Revenue, for example, has certified $135,409 to be utilized for aquatic invasive species prevention efforts in Washington County, Minnesota for 2021. County officials will utilize the funds in partnership with the Washington County Conservation District in order to provide countywide aquatic invasive species control focused operations, including watercraft inspections, early detection, rapid response, and outreach education efforts. It is important to point out that Minnesota’s aquatic invasive species (AIS) prevention aid program has provided $10 million dollars to Minnesota counties each year since 2014.

Minnesota’s robust spending to support the fight against exotic aquatic invasive species doesn’t stop with the $10 million dollars that is annually appropriates to counties through the AIS prevention aid program, the state legislature also appropriates a $9 million budget to the Department of Natural Resources in order to support operations related to aquatic invasive prevention and enforcement each year. What is particularly important for our readers to understand is that Minnesota funds it’s robust exotic aquatic invasive species management programs in large part by levying a $10.60 aquatic invasive species surcharge on each three-year watercraft registration, a $5.00 aquatic invasive species surcharge on the sale of each non-resident fishing license, an annual AIS control activities dedicated appropriation from the Minnesota state legislature, and a modicum of federal funding. Minnesota’s lake associations spend an additional $1.65 million per year on activities related to the protection of their respective lakes from the potential ravages of exotic aquatic invasive species.

It is important to note that the justification for the establishment of an aquatic invasive species surcharge of $10.60 on every three-year recreational watercraft registration in Minnesota is derived from the fact that recreational watercraft owners utilizing public boating access sites are known to be an important in-water vector for the secondary spread of exotic aquatic invasive species. By often neglecting to inspect their boat, trailer, and related equipment, and/or by failing to take the time to remove visible exotic aquatic plant fragments, or animals such as Eurasian water milfoil, or zebra mussels before transporting their craft to a new public boating access site, recreational boaters are considered major contributors to a growing and increasingly difficult to fund and manage exotic aquatic invasive species related problem that exists in Minnesota, Michigan, Wisconsin, and throughout the freshwater ecosystem inundated upper Midwest.

The state’s exotic aquatic invasive species control program also includes a Minnesota Department of Natural Resources administered Preventing Aquatic Invasive Species through Behavior Change program that aims to promote the adoption of desirable aquatic invasive species (AIS) prevention behaviors and create positive social norms supporting AIS prevention in Minnesota.

Minnesota’s relatively well-funded and robust exotic aquatic invasive species control program is administered by the Minnesota Department of Natural Resources in collaboration with the  Minnesota DNR AIS Advisory Committee, local units of government, native American tribes, surrounding states and Canadian provinces, multi-jurisdictional groups concerned about the spread of aquatic invasive species, academic researchers, and in particular those assigned to the University of Minnesota-based Minnesota Aquatic Invasive Species Research Center,  Using “innovative science to identify solutions to Minnesota’s AIS problems”, the University of Minnesota-based center’s primary mission is to “develop research-based solutions that can reduce the impacts of aquatic invasive species in Minnesota by preventing spread, controlling populations, and managing ecosystems; and to advance knowledge to inspire action by others.”

Readers of the Michigan Waterfront Alliance newsletter should look forward to addition articles and information regarding Minnesota’s robust exotic aquatic invasive species management program in the near future…