Our lake ecosystems provide us with many services including fisheries, water purification, recreation/tourism, and nutrient recycling. AIS invariably disturb those services with negative effect on the strength of the local economy.
A. Reduced Property values
Nobody wants to swim, canoe, or motor in water filled with weeds or walk on a beach littered with razor-sharp shells. And it is unsightly as well. As a result, property values are expected to drop by at least 17% when AIS infests a body of water, based on the experience of other lake communities (1a). In practical terms, this means that a lake with 200 properties, each valued at $200,000, could suffer a total reduction in property values of $6,800,000.
B. Reduced Tourism Income and Employment
AIS destroy the habitat of native game fish and thereby destroy any local economy dependent on a healthy fishery. For example, it is estimated that the invasive zebra mussels and spiny waterfleas together now filter every gallon of water in Mille Lacs every day (1b). No wonder the walleye population in Mille Lacs has crashed, taking the local economy down with it. Some resorts have seen occupancy drop by 60 percent in the last few years. Mille Lacs county has asked state lawmakers to support an economic relief program that could cost Minnesota taxpayers $10 million annually for three years (1c). Imagine the economic turmoil as zebra mussels and spiny waterfleas march across the rest of Minnesota.
Of course, the walleye crash had several causes (overfishing, warmer water) but DNR data make it clear that this dynamic duo of AIS is destroying the fish food chain.
2. Loss of lake recreational use and aesthetics.
As can be seen in the videos above, AIS quickly and permanently disrupt normal recreational use of our lakes. They have no natural predators on site so they so simply take over. It is no fun to swim, fish, sail, canoe, or motor in infested areas. Sometimes, they are downright dangerous to human health as described below.
When AIS invade our lakes and rivers, they will each have different destructive effects. Here are four major species:
A. Starry stonewort:
→Produces dense mats at the water surface (1d).
→Displaces native aquatic plants. It is such an aggressive competitor that it was recorded to even replace other non-native species, including Eurasian watermilfoil, fanwort, and curly-leaf pondweed (1d).
→Causes accumulation of phytotoxins that make sediments inhospitable for plant growth (1d).
→Reduces light availability for other submersed flora (1d).
→Interfers with spawning behavior of bass and sunfish (1d).
→Promotes growth of rootless plants such as common bladderwort and coon's tail (1d)
B. Eurasian Milfoil:
→Makes swimming impossible and has drowned several persons in some locales (2)
→Forms thick mats (see photo below), creating still water pools that become nursery areas for mosquito larvae (3).
→Clogs marine cooling systems and impacts canoeing and waterskiing (4).
→Covers the zone beginning about 3 feet offshore and extending to the point where the lake depth drops to 15 feet (5), the zone where many boaters like to take an evening cruise around the lake.
→Can reproduce from a one-inch fragment, the kind made by boat propellers chopping through the water, and grow up to 2 inches per day (6).
→Can survive being fully dried and starts new growth that will likely form rootlets (2% of batch) (7).
→Is very susceptible to freezing temperatures and is killed in 96 hours by exposure to freezing temperatures (8)
C. Zebra and Quagga Mussels
→Cause foul smelling drinking water from lakes (9a).
→Encrust docks, boats, propellers with their razor sharp shells that slice into legs and feet (see photos below) (9)
→Swim freely during their early microscopic larvae stage (called veligers) (10). Therefore, failure to unplug the bilge just one time on one boat is enough to infect your favorite lake.
→Attach to surfaces when they are still tiny: two little zebra mussels can fit end-to-end across George Washington's neck on a quarter! It is not possible that every mussel will be found every time on every watercraft! (see photo).
→Spreading through Minnesota bodies of water at a rapid pace (11).
→Clog any water pipe or cooling chamber thereby causing millions of dollars spent each year by industrial and civil installations (9, 10).
→Can jam a boat's steering equipment, putting occupants and others at risk (12).
→ "Overclean" water by feeding on algae which is a major food source for bluegill. In turn, bluegills are a food source for largemouth bass and northern pike (13).
→Love the cold. A study contracted by the US Army Corps of Engineers found (14) that adult zebra mussels can survive more than 30 days out of the water if local conditions are cold and humid. As the temperature drops (until below freezing), survival out of water increases (not decreases) greatly!
→Resist drying. It is illegal to transport zebra mussels, dead or alive, but the MN DNR does not require anyone to dry a moored watercraft after taking it from a lake infested with zebra mussels and relaunching in another body of water. It only recommends that there be a 5 or more day drying time (or high pressure-wash or rinse with very hot water) (15). On many lakes in Minnesota, there is a wide band of temperatures and relative humidity where five days drying time is NOT sufficient to kill 100% of zebra mussels (14).
95° F: ∼2 days survival
86°: ∼4 days survival
77°: ∼4.5 days survival
68°: ∼8 days survival
59°: ∼13 days survival
50°: Average low in Bemidji for muskie opener
45°: Average low in Bemidji for bass opener
41°: ∼33 days survival!
40°: Average low in Bemidji for walleye opener
34°: Average low in Bemidji for rough fish opener
32°: still alive after 2 days at freezing temperature
! ! ! ! ! sub freezing ! ! ! ! !
29°: ∼15 hours survival
27°: ∼5.5 hours survival
19°: ∼1.5 hours survival
14°: ∼1 hour survival
→Resist heat and pressure. For zebra mussel removal, it takes 140 °F water at high pressure (2,500 psi) for at least 10 seconds to kill/decontaminate the hull (or 120 °F for 2 minutes) (16). A ten second exposure on every conceivable watercraft surface is inconceivable. And, of course, a zebra mussel lodged between the hull and trailer bunks will evade detection and heat and pressure treatments.
→A case study. The community at Christmas Lake, in Shorewood, MN, made heroic AIS detection efforts (17). With the blessing of the MN DNR, the city council passed an ordinance that required AIS inspections of all boats entering the lake. The community spent $50,000 to pay for inspectors to be on site at the public launch all day every day from April to October the last two years. Money was also spent on a gate that automatically closed the launch between 10 pm and 6 am. Despite these heroic efforts, zebra mussels are now present in one bay of the lake. When asked how this could possibly happen, the city Planning Director, Brad Nielsen, said that "there are so many crevices on watercraft that some got missed. Plus, the hired inspectors did not have the authority to look in the boats nor inspect bilges or livewells" (17). The inspectors also did not have permission to inspect private watercraft launchings, another major method for AIS to slip into a body of water.
D. Spiny Waterfleas
→Degrade water quality by eating the tiny Daphnia that would otherwise be eating the algae in the lake, and that's bad for clear water (18). In addition, Daphnia are an important food source for native fishes so fish populations are adversely affected (19).
→Clog eyelets of fishing rods and prevent fish from being landed (19).
→Spread by attaching to fishing lines, downriggers, anchor ropes, and fishing nets. While female waterfleas die out of water, under certain conditions they produce eggs that resist drying and freezing, and can establish a new infestation. They also can be unintentionally transported in bilge water, bait buckets, or livewells (19).
E. Many other AIS scourges
Eurasian milfoil, zebra mussels, and spiny waterfleas alone will significantly degrade our property values. Even so, there are many other plant and animal non-native species that are a threat to the economy. The MN DNR uses a four-tiered system to classify invasive species:
Prohibited: unlawful (a misdemeanor) to possess, import, purchase, transport, or introduce these species except under a permit for disposal, control, research, or education.
Regulated: legal to possess, sell, buy, and transport but they may not be introduced into a free-living state.
Unregulated: not regulated under MN Invasive Species Statues, but there are regulations for fishing, hunting, or transporting these species.
Unlisted: not prohibited, regulated, or unregulated.
AIS have penetrated deep into the heart of Minnesota, nearer and nearer to the magnificent headwaters of the Mississippi River. Zebra mussels, starry stonewort, Eurasian milfoil, faucet snails, and banded mystery snails are within 60 miles of this national treasure (20).
4. Method of Spreading
Several studies show that it is human boating practices, not bird behavior, that is responsible for the spread of AIS (21, 22). For example, one study conducted on Lake St. Clair in Wisconsin (22) showed that mallard ducks transported on average less than one zebra mussel larva per trip as they left the lake which is infested with zebra mussels. At the same time, most boats examined on Lake St. Clair had an average of 4200 zebra mussel larvae in each of their 9 gal live-well systems.
5. AIS detection
Transporting many AIS is illegal (23) but no one can realistically inspect every inch of their boat hull looking for grain-sized zebra mussels or get down on their knees and look for specks of milfoil.
6. Many different personalities and ideas
All Minnesotans love our lakes and rivers and there is a wide spectrum of concern on throughout the state about the threat of AIS. Some feel it is overblown. Others are worried to the point of trying to stop development of new launches. Some are concerned but do not have the time, money, or training to get involved.
"Clean, Drain, Dry" is the motto of the DNR when it comes to controlling AIS. However, these three seemingly simply instructions are extremely difficult to carry out. Killing/removing AIS is difficult, time-consuming, and costly as discussed above. All equipment must be decontaminated and includes but is not limited to: docks, trailers, hulls, INTERNAL water cooling systems, bilges, livewells, anchors, mooring and anchor lines, inflatables, downriggers, planing boards, water skis, wakeboards, ropes, fishing gear, bait buckets, and stringers (23).
The penalty for introducing AIS into a Minnesota lake is not commensurate with the violation. For example, if an uncaring or uninformed individual transports AIS to a lake with 200 properties, each valued at $200,000, the total reduction in property values could reach $6,800,000. However, the penalty is only $500 "for placing or attempting to place into waters of the state water-related equipment that has prohibited invasive species attached when the waters are not listed by the commissioner as being infested with that invasive species". (24).
It is impossible to adequately train 100% of all Minnesota water users on all types of AIS. Even if this were possible, the knowledge, skill, and dexterity needed for decontamination render the exercise unrealistic.
→Minnesotans wish to continue to enjoy the exceptional quality and beauty of those invaluable resources.
→Some forms of AIS can last more than 30 days out of the water under some of the weather conditions that occur in our lakes and rivers.
→We can neither detect nor remove all forms of AIS that may be present on all watercraft and other items brought to our lakes and rivers 100% of the time.
→It is clear that governmental regulations and suggestions are having insufficient success in stopping the progression of AIS.
→A single error in detection and/or removal may cost a Minnesota lake its quality and beauty.
→A prolonged deep freeze in a dry environment will kill AIS.
→We are committed to make the individual and collective sacrifices necessary to maintain the wonderful attributes of Minnesota lakes and rivers.
MN COLA serves to coordinate the efforts of all lake, river, and watershed associations in Minnesota, related to shoreline preservation and restoration, water quality, prevention of aquatic invasive species (AIS), and sustainable uses and development for bodies of water in all counties, which include: Aitkin, Anoka, Becker, Beltrami, Benton, Big Stone, Blue Earth, Brown, Carlton, Carver, Cass, Chippewa, Chisago, Clay, Clearwater, Cook, Cottonwood, Crow Wing, Dakota, Dodge, Douglas, Faribault, Fillmore, Freeborn, Goodhue, Grant, Hennepin, Houston, Hubbard, Isanti, Itasca, Jackson, Kanabec, Kandiyohi, Kittson, Koochiching, Lac Qui Parle, Lake, Lake Of The Wood, Le Sueur, Lincoln, Lyon, Mahnomen, Marshall, Martin, McLeod, Meeker, Mille Lacs, Morrison, Mower, Murray, Nicollet, Nobles, Norman, Olmsted, Otter Tail, Pennington, Pine, Pipestone, Polk, Pope, Ramsey, Red Lake, Redwood, Renville, Rice, Rock, Roseau, St. Louis, Scott, Sherburne, Sibley, Stearns, Steele, Stevens, Swift, Todd, Traverse, Wabasha, Wadena, Waseca, Washington, Watonwan, Wilkin, Winona, Wright, and Yellow Medicine.
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