AQUATIC INVASIVE SPECIES (AIS)--Why Should we be Concerned About AIS?
1. Reduced property values. Our property values are expected to drop by at least 17% 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 three major species:
A. EURSASIAN 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% of batch) (7).
→Is very susceptible to freezing temperatures and is killed in 96 hours by exposure to freezing temperatures (8)
B. 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).
→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:
- 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 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 Long Lake, 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).
→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.
C. 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 ian important food source for native fishes so fish popluations 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).
Eurasian milfoil, zebra mussels, and spiny waterfleas 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:
non-native common reed,
reed canary grass,
non-native waterlilies (Nymphaea spp.),
banded mystery snails,
Chinese mystery snail,
New Zealand mud snail,
3. AIS Proximity
Zebra mussels are now next door in lakes such as Big Rice, Andrusia, and Wolf, and the Mississippi River out of Wolf, all the way to the Power Dam. Eurasian milfoil is now in Leech Lake (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 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.
"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 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).
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.
9. Summary and Pledge
- →We, the lovers and users of Long Lake, wish to continue to enjoy the exceptional quality and beauty of Long Lake.
→Some forms of AIS can last more than 30 days out of the 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 regulations 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 make 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.