Long Lake Association

AIS

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Aquatic Invasive Species (AIS) — Why Should We Be Concerned?

AIS, otherwise known as aquatic invasive species, is a freshwater or marine organism that has spread or been introduced beyond its native range, and is either causing harm or has the potential to cause harm. These invasive species can lead to the extinction of native plants and animals, destroy biodiversity, and permanently alter habitats through both direct and indirect effects.

So, why should Long Lake NE homeowners be concerned?

  1. Reduced property values: Our property values are expected to drop by at least 17 percent if AIS infests Long Lake, based on the experience of other lake communities.1
  2. Loss of lake use and view: If AIS invade Long Lake, they will each have different destructive effects. Here are the three major species:

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 Long Lakers 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 percent of the batch).7
  • Is very susceptible to freezing temperatures and is killed in 96 hours by exposure to freezing temperatures.8

ZEBRA MUSSELS

  • 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 Long 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 below).
  • 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
  • “Over clean” water by feeding algae which is a major food source for bluegill. In turn, bluegills are a food source for large mouth bass and northern pike.13
  • Love the cold: A study conducted by the US Army Corps of Engineers found14 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:

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 drying: It is illegal to support 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 it 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 Long Lake, there is a wideband temperature and relative humidity where five days drying time is NOT sufficient to kill 100 percent of zebra mussels.14
  • 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 (of 120° F for 2 minutes).16 A 10-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 live wells.”17 The inspectors also did not have permission to inspect private watercraft launching, another major method for AIS to slip into a body of water.

SPINY WATER FLEAS

  • 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, down riggers, anchor ropes, and fishing nets. While female water fleas 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 live wells.19

Eurasian milfoil, zebra mussels, and spiny water fleas alone will significantly degrade our property values. Even so, there are many other plant and animal AIS as well that are known to be in Minnesota waters.

PLANTS:

ANIMALS:

AIS PROXIMITY

Zebra mussels are now next door in lakes such as Big Rice, Andrusia, and Wolf, as well as the Mississippi River out of Wolf, all the way to the Power Dam. Eurasian milfoil is now in Leech Lake.20

METHOD OF SPREADING

Several studies show that it is human boat practices, not bird behavior, that is responsible for the spread of AIS.21, 22 For example, one study conducted on Lake St. Clair in Wisconsin22 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 4,200 zebra mussel larvae in each of their 9 gal live-well systems.

AIS DETECTION

Transporting many AIS is illegal23 but no one can realistically inspect every inch of their boat looking for grain-sized zebra mussels or get down on their knees and look for specks of milfoil.

MANY DIFFERENT PERSONALITIES AND IDEAS

All Long Lakers love the lake and there is a wide spectrum of concern on Long Lake 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.

DECONTAMINATION

“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, live wells, anchors, mooring and anchor lines, inflatables, down riggers, planing boards, water skis, wake boards, ropes, fishing gear, bait buckets, and stringers.23

PENALTIES

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 Long Lake, over $1,000,000 in reduced property values could be the result. However, the penalty “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” is only $500.24

TRAINING

It is impossible to adequately train 100% of all Long Lake water users on all types of AIS. Even if this were possible, the knowledge, skill, and dexterity needed for decontamination render the exercise unrealistic.

SUMMARY AND PLEDGE

  • We, the lovers and users of Long Lake, wish to enjoy the exceptional quality and beauty of Long Lake.
  • Some forms of AIS can last more than 30 days out of water under some of the weather conditions that occur at Long Lake.
  • We can neither detect nor remove all forms of AIS that may be present on all watercraft and other items brought to Long Lake 100% of the time.
  • It is clear that governmental regulation and suggestions are having insufficient success in stopping the progression of AIS.
  • A single error in detection and/or removal may cost Long Lake its quality and beauty.
  • A prolonged deep freeze in a dry environment will kill AIS.
  • Isolation from other bodies of water is the only practical chance of keeping Long Lake free of AIS.
  • We are committed to making the individual and collective sacrifices necessary to maintain the wonderful attributes of Long Lake. This includes the hassle of using different watercraft when visiting other lakes, streams, and rivers.

REFERENCES

  1. AIS Economic Impact
  2. Eurasian milfoil drowning
  3. Eurasian milfoil and mosquitoes
  4. Eurasian milfoil cost on Lake Minnetonka
  5. Eurasian milfoil technical information
  6. Eurasian milfoil reproduction
  7. Eurasian milfoil survival after 100% desiccation
  8. Eurasian milfoil killed by freezing
  9. Zebra mussel life cycle and industrial impacts
  10. Zebra mussel facts
  11. Zebra mussel spread
  12. Zebra mussel and boat steering equipment
  13. Zebra mussel effects on large mouth bass and northern pike
  14. Zebra mussel survival out of water
  15. Zebra mussel transportation recommended drying time for day-use watercraft
  16. Zebra mussel decontamination with hot water
  17. Zebra mussel infestation of Christmas Lake, MN: Conversation with Brad Nielsen, Planning Director, City of Shorewood, MN, Oct. 28, 2014.
  18. Spiny water fleas and water quality
  19. Spiny water fleas and fishing
  20. MN DNR list of infested waters
  21. AIS transport by birds
  22. AIS transport by birds
  23. Illegal transport of AIS
  24. Penalty for introduction of AIS