1.9.15 S7 Aquatic Invasive Species - Weeblycetg.weebly.com/uploads/3/9/7/0/39707378/1.9.15_s7... ·...

7-1

Section 7

About Aquatic Invasive Species

The Great Lakes...darkly reflect how a global

tradefest can turn into an ecological makeover. What

was once a distinct North American body of water...is

now little more than a degraded multicultural

aquarium.

—Andrew Nikiforuk, Pandemonium1

Introduction Section 7 describes the aquatic invasive species

(AIS) that are living in or near Lac du Flambeau and

presents data from a survey on residents’

perceptions of AIS.

People transport organisms around all the time.

Sometimes when a non-native species is brought

into a new area the species will take over and

spread rapidly and widely throughout the area.

When this happens, the spread can cause major

harm to the native ecosystem or humans. When

non-native plants, animals, or pathogens rapidly

take over a new location and alter the ecosystem,

they are called invasive species.4

There is little doubt that AIS have negative impacts

on Wisconsin.5 AIS are one of the newer threats to

Wisconsin lakes, and residents spend several million

dollars each year trying to control AIS, costs that are

increasing every year.6

Of the many dozens of AIS that now make their

homes in Wisconsin, several have found their way to

Vilas County and other counties near Lac du

Flambeau, and even to the lakes and wetlands of

Lac du Flambeau (Table 7-1 and Table 7-2).

Table 7-1. Presence of AIS Near or in Lac du Flambeau*

AIS Oneida County

Price County

Vilas County

Iron County LdF

Banded Mystery Snail X X X X X

Chinese Mystery Snail X X X X X

Curly Leaf Pondweed X X X X

Eurasian Water Milfoil X X X X

Freshwater Jellyfish X X X X

Purple Loosestrife X X X X X

Reed Canary Grass X X

Rusty Crayfish X X X X X

Smelt X X X

Spiny Waterflea X X

*Data from variety of WDNR reports January 2014

The waters of Lac du Flambeau are clearly at risk.

Several lakes have infestations of rainbow smelt,

purple loosestrife, or rusty crayfish, while other AIS

like Eurasian water milfoil and curly-leaf pondweed

are moving ever closer. In the past few years curly-

leaf pondweed was found in Island Lake in

Manitowish Waters and in Lost Lake in St. Germain

in Vilas County, and on the Rainbow Flowage in

Oneida County; Eurasian water milfoil was found in

Kentuck Lake in Vilas County; zebra mussels were

found in Keyes Lake in Florence County; and the

Friends I am a boater, and like you I love our lakes.

I've been hearing about these aquatic invaders in

our state.

Non-native plants and animals, threaten waters

far and wide.

They’d love to make their way into a lake they’ve

never tried.

—Partial lyrics for the folk song, The Ballad of Aquatic Invasive Species, Scott Gatzke2

Wisconsin Statute Section 23.22 (1) (c) officially

defines invasive species as “nonindigenous species

whose introduction causes or is likely to cause

economic or environmental harm or harm to human

health.”3

7-2 Section 7: About Aquatic Invasive Species

Bear River Watershed Comprehensive Lake Management Plan

Chinese mystery snail was confirmed in Little

Crawling Stone Lake and Pokegama Lake in Lac du

Flambeau. As recently as 2013, Eurasian water

milfoil was found in Smokey Lake in Phelps and in

Lost Lake in St. Germain, and, in 2014, the spiny

waterflea was found in Trout Lake.7

Despite the prevalence of Eurasian water milfoil and

curly-leaf pondweed in Vilas County and counties

nearby, Lac du Flambeau is currently free of them

and the problems associated with them. Even so,

their presence nearby has fueled apprehension that

these and other AIS may eventually infest lakes and

wetlands in Lac du Flambeau, harming local

ecosystems, native plant species, and traditional

gathering resources while threatening human health,

the economy, and property values.

There is concern, too, that climate change could

increase the probability that new introductions of AIS

may replace native aquatic plants while

exacerbating the spread of AIS already in the area,

again at the expense of native plants.8

Table 7-2. Aquatic Invasive Species in Lac du Flambeau Lakes*

Waterbody Smelt Rusty

Crayfish Purple Loose-

strife*** Fresh Water

Jellyfish

Chinese Mystery Snail

Banded Mystery Snail

Reed Canary Grass

Big Crawling Stone Lake** 1975 1986

Fence Lake** 1968 2007 2010

Gunlock Lake 2008 2007

Flambeau Lake** 1968 2008

Ike Walton Lake**

Little Crawling Stone Lake** 1982 2002 2011 2010

Little Trout Lake** 1990 X X

Long Interlaken Lake** 1983 2013 2013

Lower Sugarbush X

Middle Sugarbush X X

Moss Lake** 1989 X

North Twin Placid Lake 1996

Pokegama Lake** 1996 1986 2011

Powell Marsh** X

Shishebogama Lake X 2010

South Twin Placid Lake X

Squaw Lake 1963 1961 2004

Toto Tom Lake 1990 X

Upper Sugarbush 1975

White Sand Lake** 2002 2008 X

Wild Rice Lake 1975 2010 2010 2006

*Table compiled from several WDNR reports of January 2014. X = date unknown **Focus of the Bear River Watershed Comprehensive Lake Management Plan ***Information for Purple Loosestrife from WDNR & Lac du Flambeau reports

Section 7: About Aquatic Invasive Species 7-3


Aquatic Invasive Species Mystery Snails There are three species of mystery snails in

Wisconsin, (Chinese mystery snail, banded mystery

snail, and brown mystery snail, but only the brown

mystery snail is native to Wisconsin.9

In Lac du Flambeau presently, the Chinese mystery

snail (Figure 7-1) is in Little Crawling Stone,

Gunlock, Long Interlaken, Pokegama,

Shishebogama, Squaw and Wild Rice Lakes, and

the banded mystery snail (Figure 7-2) is in Fence,

Little Crawling Stone, Long Interlaken,

Shishebogama, South Twin Placid, and Wild Rice

Lakes (Table 7-2).

Not much is known about these invasive snails,

though it appears they have a negative effect on

native snail populations. Their large size and hard

operculum (a trap door cover which protects the soft

flesh inside) and their thick hard shell make them

less edible for predators, like rusty crayfish, an

invasive widely spread throughout Lac du

Flambeau.10

The Chinese mystery snail came from southeast

Asia, Japan, and eastern Russia, where it is a food

source, while the banded mystery snail is native to

North America.11

The Chinese mystery snail is believed to have been

sold originally in a Chinese food market in San

Francisco in the late 1890s; collected and used as

early as 1914 in Boston; and likely released from

someone’s aquarium into the Niagara River

sometime between 1931 and 1942.12

The banded mystery snail was likely spread by an

amateur conchologist who purposefully released

around 200 of the snails simultaneously into the

Hudson River. The snail probably dispersed by itself

following this event, but more recent introductions

were likely made via release from aquaria.13

Figure 7-1. Chinese Mystery Snail

Figure 7-2. Banded Mystery Snail

Little is actually known about either of the invasive

snails, including their sex life. The snail is a mystery

because in the spring when it gives birth, its young

are fully-developed snails that suddenly and

mysteriously appear.14

There has been much discussion among scientists

on whether the banded mystery snail is a potential

carrier of the swimmer’s itch parasite, but to date no

banded mystery snails have been found carrying the

parasite.15



Mystery snails thrive in silt and mud areas although

they can be found in lesser numbers in areas with

sand or rock substrates. They are found in lakes,

ponds, irrigation ditches, and the slower portions of

rivers and streams. They are tolerant of pollution

and often thrive in stagnant water areas.16

Lakes with high densities of mystery snails often see

large die-offs of the snails which are related to the

lake’s warming and resulting low oxygen (related to

algae blooms).17

Despite being classified as an invasive, mystery

snails are still available for sale through the internet

to aquarium enthusiasts who rely on them to keep

tanks free of unwanted algae.18

Curly-Leaf Pondweed Curly-leaf pondweed (Figure 7-3 and Figure 7-4) is a

non-native submerged aquatic plant that has a

unique ability to thrive in cool water, allowing it to

out-compete other aquatic plants.19

The plant is

currently not in any lake in Lac du Flambeau, though

it is in lakes in Vilas County and other counties

nearby (Table 7-1).

Figure 7-3. Curly-Leaf Pondweed

Figure 7-4. Infestation of Curly-Leaf Pondweed

Curly-leaf pondweed is one of 80 pondweed species

found throughout the world. It is native to the fresh

waters of Eurasia, Africa and Australia.20

The plant was accidentally introduced into the

United States when the common carp was brought

here during the mid 1800s. It is thought to have

made its way to Wisconsin in 1905 along with fish

imported from Europe.21

Curly-leaf pondweed has a unique life cycle. Unlike

most native aquatic plants that come out of

dormancy in spring and reach their maximum growth

in late summer or early fall, curly-leaf pondweed

normally begins growing in the fall.22

Depending on snow cover and winter severity, curly-

leaf pondweed may be dormant or actively growing

under ice. Its natural inclination for low water

temperatures helps it avoid competition with other

plant species. Its fast early spring growth allows the

stems to reach the water’s surface before any other

plant, and by late spring, a dense canopy of curly-

leaf can form, blocking sunlight from reaching other

native plants (Figure 7-5).23

Figure 7-5. Infestation of Curly-Leaf Pondweed

Curly-leaf pondweed plants usually complete their

life cycle in June or July, when they die back,

forming large mats of dying vegetation on the

surface which release nutrients such as phosphorus

into the water, fueling algal blooms.24

Turions and seeds are formed on the plants before

they die. A turion (Figure 7-6) is a dormant shoot



segment (vegetative bud) that can form almost

anywhere on the plant. It is a hard structure that

looks a little bit like a burr or pinecone.25

Figure 7-6. Turion of Curly-Leaf Pondweed

Although the plants also produce seeds, the turions

are likely its most reliable form of reproduction. The

turion falls to the bottom of the lake as the plant dies

and begins to decay. Most of the turions begin to

sprout in fall, responding either to the shortening day

length or to water temperature. However, some

turions will actually sprout in the spring and some

will lie dormant in the sediment until environmental

conditions are favorable for sprouting. Turions can

remain dormant for years.26

For the plants that sprout in the fall, the initial growth

form is a winter foliage that stays green, sometimes

dormant or sometimes actively growing, even under

the ice. The curly-leaf pondweed foliage in winter to

early spring are quite narrow and lack the wavy

edges.27

A few days after ice-off, curly-leaf pondweed begins

to grow more rapidly and attain its spring foliage

(lasagna noodle-like wavy, hairy edges with a crispy

appearance). Turions that sprout in the spring also

have narrow non-wavy leaves when the plant first

sprouts, then the wavy leaves develop as the plant

matures.28

Eurasian Water Milfoil Eurasian water milfoil (EWM) is a submerged

aquatic plant that poses a serious threat to a lake’s

native aquatic plants and the animals that depend

on diverse ecosystems.29

EWM (Figure 7-7) is not

currently in any lake in Lac du Flambeau, but it is

found in Vilas County and other nearby counties

(Table 7-1).

Figure 7-7. Comparison of EWM with the Native Northern Water Milfoil

There are 11 native water milfoil species in North

America. Of these, seven are native to Wisconsin.

The native water milfoils are not as aggressive as

the exotic water milfoil and they have natural

predators. Some Wisconsin species of water milfoil

are quite rare and are on the Wisconsin Threatened

and Endangered species list.30

EWM can form thick underwater stands of tangled

stems and vast mats of vegetation at the water’s

surface. It can crowd out native plants and become

so thick that the larger fish cannot swim through the

tangled mats. When EWM mats get well established,

channels are needed to allow access from the

shoreline out into deeper water areas. EWM is now

one of the most troublesome submerged aquatic

plants in Wisconsin.31

EWM is native to Europe, Asia, and northern Africa.

It may have been brought in to the United States via

aquaculture and the aquarium trade. The first

authenticated record of EWM in the United States

was in 1942 in a Washington D.C. pond. In 2007 it

was found in 48 of the 50 states. EWM was first

documented in Wisconsin in the 1960s.32

EWM is an evergreen plant that remains alive over

the winter and starts growing when water tempera-

tures reach 50oF. EWM begins growing earlier in the

season than the native water-milfoils, making early

spring chemical treatment an option for its control.33



In spring and summer, EWM can grow up to two

inches a day in water depths ranging from less than

one foot to over 20-feet. Thick beds can form in

water depths from 3 to 20 feet deep, but most

commonly reach nuisance levels in water depths of

6-15 feet.34

If EWM plant growth reaches the surface of a lake,

the plant will continue to grow and can form a

canopy over the surface (Figure 7-8), making the

area nearly impassable for a motor boat and

interfering with swimming and fishing, as well as

shading out native plants.35

Figure 7-8. Infestation of Eurasian Water Milfoil

Unlike curly-leaf pondweed, EWM does not produce

turions. EWM produces seeds and runners, but the

main method of plant spread is through dispersal of

plant fragments by boats and wave action.36

In the late summer and early fall, auto fragmentation

may occur, when the plant breaks itself into smaller

pieces. Plant cells at leaf nodes and side-branch

connections become weak, die, and break off. The

newly formed fragments float to new locations where

they fall to the substrate, root, and establish new

beds of EWM (Figure 7-9).37

Figure 7-9. Eurasian Water Milfoil Fragmentation

EWM has been known to hybridize with northern

water milfoil. The hybrids cannot be easily

distinguished by visual characteristics, but rather

have to be identified through DNA analysis.38

Freshwater Jellyfish The freshwater jellyfish (Figure 7-10 and Figure

7-11) found in Wisconsin are one of several species

native to China. They were first reported in North

America as early as 1884, and in Wisconsin in

1969.39

The freshwater jellyfish found in Lac du

Flambeau are in Middle Sugarbush Lake and White

Sand Lake (Table 7-2).

Figure 7-10. Freshwater Jellyfish

Adventitious roots



Figure 7-11. Freshwater Jellyfish

Although they probably evolved from descendants of

ocean jellyfish, little is known about the evolution of

freshwater jellyfish, largely because they leave no

fossil records.40

William Sowerby (1827-1906), Director of the Royal

Botanic Gardens in Regent’s Park, just outside

London, England, found male jellyfish swimming in a

large, water-lily tank among the sediments and the

root crowns of pickerelweeds only three weeks after

filling the water tank. Thinking they came from South

America with the plants, he dubbed them Amazon

jellyfish.41

In 1884, mature jellyfish polyps were found in a

water tank at Regent’s Park, and that same year,

immature polyps were found in a stream in

Pennsylvania.42

The freshwater jellyfish probably landed at both

locations as polyps or cysts attached to sediments,

water plants, or fishes. At the time – the Victorian

Era of the 1880s – maintaining water gardens and

stocking carp were the rage, and garden clubs and

aquarium societies were busy gathering the world’s

exotic plants and fishes for display and study.43

The jellyfish soon made their way to other botanical

societies, as well as to public and private aquariums

throughout England, Europe, North America, South

America, and Australia. Some were flushed into

lakes and rivers when aquariums were emptied, and

swept downstream to new waters. Others may have

hitched rides on the backs of turtles or the feet of

water birds, perhaps they even stuck to boats and

boat motors.44

After appearing in Pennsylvania waters, jellyfish

progressively moved to other states and provinces.

By the time they were first sighted in Wisconsin, they

had already been reported in 33 states, the U. S.

Territory of Hawaii, and Washington DC.45

Wood ducks have been credited, or blamed, for

introducing jellyfish to Wisconsin when they visited a

farm pond near Baraboo, Sauk County. By 2006,

jellyfish sightings had been reported for 37 natural

lakes, two dugout ponds, and one creek.46

These “jellyfish waters” vary in size from tiny ponds

to lakes of 9,842 acres (Lake Mendota) and lakes

that are 236 feet deep (Big Green Lake).47

The freshwater jellyfish has been found in a variety

of water types. They have been observed in waters

ranging from crystal clear rock quarries to soupy

green farm ponds. Preliminary research indicates

that waters high in chloride do not favor colonization

by the freshwater jellyfish.48

The extent to which freshwater jellyfish are

impacting lakes is not known. Speculation exists,

however, that since jellyfish eat zooplankton (which

are normally eaten by small fish), some negative

impacts may be taking place.49

Rusty Crayfish Rusty crayfish (Figure 7-12) are in at least eleven

lakes in Lac du Flambeau (Table 7-2). They are

native to streams in the Ohio River Basin states of

Ohio, Kentucky, Illinois, Indiana, and Tennessee.

They were likely introduced to Wisconsin waters by

anglers who used them as live bait.50



Figure 7-12. Rusty Crayfish

In Wisconsin lakes, the rusty crayfish can impact

native crayfish populations, aquatic plant

communities, and consequently entire lake

ecosystems.51

Rusty crayfish are aggressive and will chase native

crayfish from their prime habitat. When native

crayfish are chased out into the open, they are more

susceptible to predation by large fish. The rusty

crayfish consequently displace the native crayfish

and often reach high densities.52

Rusty crayfish eat small fish, insects, fish eggs, and

aquatic plants. They eat about four times the amount

of food a native crayfish eats. They are considered

messy eaters because when they snip off a plant to

eat, they often only eat small pieces of the plant and

the remainder of the plant floats away. If rusty

crayfish are eating Eurasian water milfoil, they can

actually spread the water-milfoil with their eating

habits.53

There are 330 native crayfish species in the United

States, of which 111 species are in peril of

extinction. Native crayfish are important members of

aquatic ecosystems in Wisconsin. They perform

many functions, including processing detritus and

serving as food for game fish.54

Mature rusty crayfish mate in late summer, early fall,

or early spring. The male transfers sperm to the

female, which she then stores until her eggs are

ready to be fertilized, typically in the spring (late April

or May) as water temperatures begin to increase.55

The stored sperm are released as eggs are expelled

and external fertilization occurs. The eggs attach to

swimmerets (small, leg-like appendages under the

tail). Just prior to egg laying, white patches will

appear on the underside of the female’s abdomen

(“tail section”), especially on the tail fan. These white

patches are glair, a mucus-like substance secreted

during egg fertilization and attachment. Rusty

crayfish females lay from 80 to 575 eggs.56

Eggs hatch in three to six weeks, depending on

water temperature. Once hatched, young crayfish

cling to the female’s swimmerets for three to four

molts (molting is when crayfish shed their old shell to

allow growth). Young crayfish may stay with the

female for several weeks for protection. Eventually

the young leave the female, and then undergo eight

to ten molts before they mature.57

Rainbow Smelt Rainbow smelt (Figure 7-13 and Figure 7-14) are a

small (7 to 9 inches long, weighing 3 ounces)

invasive fish. They are silvery overall with a pale

green back and iridescent purple, blue and pink on

their sides. They have a conspicuous silvery streak

running lengthwise along each side. In the water,

rainbow smelt shimmer colorfully. When removed

from the water, however, they quickly fade to a

silvery white and give off the odor of cucumbers.58

Figure 7-13. Rainbow Smelt



Figure 7-14. Rainbow Smelt

The rainbow smelt is not native to the Great Lakes.

The smelt is a saltwater species, though a

freshwater population exists in Green Lake, Maine.

Fish from this population were stocked into Crystal

Lake, Michigan in 1912. Some of the fish escaped

from Crystal Lake and were first caught in Lake

Michigan in 1926.59

Once established, the smelt population expanded

rapidly in Lake Michigan, becoming very abundant in

the 1930s. The smelt was nearly eliminated from the

lake in 1941–1942 by an unknown pathogen.

However, by the mid-1950s and into the 1960s the

fish were once again highly abundant.60

Smelt have been present in Wisconsin waters of the

Great Lakes for over 70 years, first discovered in

1928 in Little Sturgeon Bay in Door County. Through

the intentional or accidental efforts of private

individuals, smelt began to spread to Wisconsin’s

inland waters in the 1980s.61

Lac du Flambeau

currently has twelve lakes confirmed to have

rainbow smelt; Crawling Stone Lake being the first in

1975, and Pokegama and North Twin Placid Lakes

in 1996 (Table 7-2).

Few smelt live beyond five years of age. Both sexes

become sexually mature at about two years of age.

A female may produce 33,000 to 75,000 eggs in one

season, depending on her size. The spawning

season takes place in early spring. Larvae and

juveniles feed upon zooplankton, particularly

microscopic crustaceans. Adult smelt feed on small

crustaceans and fish.62

Fish biologists have clear data showing distinct

negative impacts of smelt on the sport fish

populations of Wisconsin’s inland lakes. For

example, smelt compete directly with juvenile

walleye for food, which may be a principal

mechanism in limiting walleye recruitment. They

compete with other native fish for food as well. Smelt

will even eat other fish in their early or larval life

stages. These larval fish or fry can include lake trout,

whitefish, walleye and cisco, a forage species native

to Wisconsin.63

The Tribal fish hatchery raises and stocks brown

trout to counter the influence of the rainbow smelt,

an invasive fish that can cause serious harm to the

walleye fishery in Lac du Flambeau. Rainbow smelt

and walleye inhabit the same spawning areas, but

the smelt tend to arrive first to lay their eggs. When

hatched, the smelt may eat the eggs of the newly

arrived walleye as well as the zooplankton that

walleye fry would ordinarily eat. The young smelt

then move to the deeper water where they and adult

smelt eat what would ordinarily be available for the

walleye when they arrive later. The life-cycle of the

brown trout is such that when they are introduced to

the lake, they dine on the smelt and serve as a

biological control favoring the walleye.64

There is some evidence that the rate mercury

accumulates in top level fish consumers accelerates

when they switch to a diet of smelt. Rainbow smelt

are also rich in thiaminase, an enzyme that destroys

thiamin, which is necessary for development of fish

embryos. As lake trout and other sport fish consume

the smelt, their ability to successfully reproduce

diminishes because of thiamin deficiency.65

Waterfleas The spiny waterflea and fishhook waterflea (Figure

7-15) infest lakes in Vilas County, but not in Lac du

Flambeau (Table 7-1).



Figure 7-15. Spiny and Fishhook Waterfleas

Spiny and fishhook waterfleas are often first noticed

by anglers when the invasives become entangled on

fish lines (Figure 7-16), anchors, downrigger cables,

and other types of gear used in boating activities.66

Figure 7-16. Spiny Waterfleas on Fishing Line

In addition to causing problems for anglers and

recreational users, the invasive waterfleas have the

potential to disrupt food webs.67

Spiny and fishhook waterfleas are large (up to ¾

inch) predatory crustacean zooplankton that eat

smaller zooplankton, including Daphnia (native

waterfleas). This puts them in direct competition with

young fish that also eat native zooplankton.68

Like juvenile fish, spiny and fishhook waterfleas will

“stalk” their prey. And, like most invasive species,

they lack predators that can keep their population in

check. Young fish have trouble eating the spiny and

fishhook waterfleas due to their long, spiny tails.69

Spiny and fishhook waterfleas are native to parts of

Europe and Asia. Both species of waterfleas entered

the Great Lakes in ship ballast water from Europe.

The spiny waterflea arrived in the 1980s, followed in

the 1990s by the fishhook waterflea. One or both

species are now found in all of the Great Lakes.70

Their resting eggs can survive long after the adults

are dead, so the eggs, as well as the waterfleas,

may be transported via water between an infested

lake to a non-infested lake.71

Reproductive females carry their offspring on their

backs in a balloon-like brood pouch, which can be

filled with either developing embryos or resting

eggs.72

Most of the time, female spiny and fishhook

waterfleas exhibit rapid asexual reproduction where

females produce from one to ten eggs that are able

to develop into new females without mating or

fertilization. The new females are genetic replicas, or

clones, of the mother. The generation time of this life

cycle (embryo to adult female) varies with water

temperature because rates of metabolism rise and

fall with temperature.73

During the summer, when the surface water of the

lake is warm, waterfleas can produce a new

generation in less than two weeks. Since males are

not needed for reproduction, they are rarely found

when food is plentiful or when environmental

conditions favor rapid population growth.74

For spiny and fishhook waterfleas, sex of offspring is

not determined genetically, but rather by

environmental factors. When food becomes limited

or when the lake cools in the fall, males begin to

appear. Declining environmental quality can be

sensed by adult females, who respond by producing

male rather than female offspring. These males are

able to mate with surviving females, producing

resting eggs. The resting eggs are first carried as

orange-brown spheres in the female brood pouch.

They are later released and fall to the lake bottom

where they can survive the cold winter. In spring or

early summer, these eggs hatch into juvenile

females that begin the asexual reproduction again.75



Resting eggs can remain dormant for long periods of

time, and they offer an explanation for the arrival of

spiny and fishhook waterfleas in North America.76

Reed Canary Grass Reed canary grass (Figure 7-17) is found in 500,000

acres of wetlands, moist meadows, and riparian

areas throughout Wisconsin.77

In Lac du Flambeau,

it is in the Powell Marsh and near Little Trout Lake

(Table 7-2).

Reed canary grass is the “poster plant” for disturbed

wet sites. It forms dense stands in places where

clearing, grading, siltation, filling, or other disruptions

have created an opening with moist soil. A Eurasian

strain has been used for erosion control and lowland

pastures, but its aggressive growth has made it a

threat to native wetland plants.78

Reed canary grass is one of the first grasses to

appear in the spring and can grow 6-7 feet above

the soil surface. It reproduces by seed, by stem

fragments, and horizontal stems (rhizomes).79

Reed canary grass is one of the first wetland plants

to emerge in the spring, enabling it to shade out

native species that emerge later in the growing

season. It can stay green and actively growing well

past the first killing frost in autumn.80

Reed canary grass seeds and rhizomes readily float,

making streams and ditches networks for effective

dispersal by humans and wildlife. The seeds readily

adhere to moist skin or fur and are transported by

clothing, equipment, and vehicles.81

Yellow Flag Iris Yellow flag iris (Figure 7-18) is a beautiful, robust,

showy plant that is native to Europe, British Isles,

North Africa, and the Mediterranean Region.82

Currently, it is not found in Lac du Flambeau (Table

7-1).

Figure 7-18. Yellow Flag Iris

Yellow flag iris is also known as yellow Iris, water

flag, European yellow-Iris, and pale yellow iris.83

Yellow flag iris grows fast and spreads rapidly. Its

roots establish dense mats that support thickets of

three to six foot plants in shallow water along the

shorelines, crowding out beneficial native plants. It

spreads within an established site through root

growth, and to new locations by dropping seeds into

the water.84

While very young plants can be removed by hand-

digging or pulling, removing mature

plants typically requires equipment

that is likely to cause considerable

ground disturbance and increase the

potential for shoreline erosion.85

All parts of the plant are poisonous,

limiting the source of food for wildlife

in the areas where it dominates.86

There are presently no known

biological agents for effectively

Figure 7-17. Infestation of Reed Canary Grass



controlling yellow flag iris. There are suitable

herbicide options, but only chemicals approved by

the Wisconsin Department of Natural Resources

may be applied and then only by licensed

professionals with a WDNR permit.87

Purple Loosestrife Purple loosestrife (Figure 7-19) is an invasive

perennial that has spread rapidly in North American

wetlands, shorelines, and roadside ditches. Lac du

Flambeau has several infestations of the plant. See

Section 6 of this document for details.

Thick stands of

purple loosestrife

crowd out native

plants and reduce

food, shelter, and

nesting sites for

wildlife, birds,

turtles, and frogs.

Purple loosestrife

was introduced to

the United States

in the 1800s in

discarded soil and

water that had

been used for ship ballast. The plant, too, was

imported to sustain bee keeping and gardening

businesses. This European species has since

invaded nearly every U.S. state and at least six

Canadian provinces.

Due to the prevalence of infestations in Lac du

Flambeau, the Tribal Natural Resources Department

and the Town Lakes Committee have worked

together to control the infestations.

Results of Community Survey The process used to prepare the Bear River

Watershed Comprehensive Lake Management Plan

included mailing a survey to 3,000 households in

Lac du Flambeau. The survey posed questions

about topics like residents’ perceptions of the quality

of lake water, fishery, and overall environment;

current and ideal shoreline landscaping; interests in

attending a variety of workshops; and knowledge of

Aquatic Invasive Species and aquatic plants.88

Almost one-third (996 of 3,000) of the surveys were

returned completed, representing fifty-one lakes. Of

the 996 completed surveys, 576 are from

households affiliated with the ten lakes of focus in

the Bear River Watershed Comprehensive Lake

Management Plan.89

The remainder this section presents the survey

results for the questions related to aquatic invasive

species.

In order to help establish the extent to which

residents are knowledgeable about AIS, the survey

asked residents whether they had heard about AIS

prior to reading the survey.

Other than for Little Trout Lake, Flambeau Lake, and

Pokegama Lake, approximately one-third (Table

7-3) of the respondents indicate they had prior

knowledge of AIS.

Table 7-3. Prior Knowledge of AIS

Lake # Surveys Completed

# of YES Responses

% of YES Responses

Big Crawling Stone 96 33 34%

Little Trout 3 0 0%

Fence 123 43 35%

Long Interlaken 31 10 32%

Flambeau 54 10 19%

Moss 27 10 37%

Ike Walton 23 8 35%

White Sand 102 34 33%

Little Crawling Stone 34 10 29%

Pokegama 83 13 16%

Bear River Totals 576 171 30%

Figure 7-19. Purple Loosestrife



The survey asked the residents who indicated they

had prior knowledge of AIS to identify from a list of

items, such as water quality and native fish, what

they believe is threatened by AIS.

Table 7-4 shows the percentages of responses for

each lake as well as totals for all ten lakes. For

example, of the 33 respondents for Crawling Stone

Lake, 42% believe that AIS threaten lake water

quality, 55% believe that AIS threaten native fish,

and so on.

Residents who had indicated that they had prior

knowledge of AIS were also presented with a list of

AIS and asked to identify which of them, if any, they

believe are currently in the lake (Table 7-5).

In addition to showing the percentages of

respondents who believe that particular AIS are

present in the lake, the table shows whether the AIS

are actually in the lake. For Crawling Stone Lake for

example, 18.2% of the respondents believe that the

banded mystery snail is in the lake, though in

actuality it is not.

The questionnaire asked residents who had

indicated that they had prior knowledge of AIS if they

have been taking time to look for AIS in the lake.

Table 7-6 shows the percentages of time that

respondents said they have been spending looking

for AIS. Of the 31 respondents for Crawling Stone

Lake, for example, 38.7% have not looked for AIS,

29% have looked once a season, 9.7% monthly,

9.7% weekly, and 12.9% daily.

The questionnaire asked residents who had

indicated that they had prior knowledge of AIS about

the extent to which they are concerned about AIS.

Table 7-7 shows the percentages of degree of

concern about AIS. Of the 33 respondents for

Crawling Stone Lake, for example, 36.4% are

extremely concerned about AIS, 51.5% are

somewhat concerned, 3% are not too concerned,

and 5% are unsure.

Table 7-4. Lake Resident Survey on Lakes Perceived to be Threatened by AIS

Lake #

Respondents

Lake Water Quality

Native Fish

Native Aquatic Plants

Native Shoreline

Plants Amphibians Wetlands Crustaceans Air

Quality Other

Big Crawling Stone 33 42% 55% 36% 33% 33% 33% 33% 6% 3%

Little Trout 0 0 0 0 0 0 0 0 0 0

Fence 43 49% 40% 37% 21% 9% 12% 7% 0% 5%

Long Interlaken 10 40% 20% 10% 10% 10% 0% 20% 0% 10%

Flambeau 10 40% 40% 20% 40% 40% 20% 30% 20% 0%

Moss 10 50% 40% 50% 40% 20% 30% 30% 20% 0%

Ike Walton 8 50% 25% 25% 38% 25% 25% 13% 13% 0%

White Sand 34 47% 38% 16% 21% 6% 3% 9% 0% 0%

Little Crawling Stone 10 60% 60% 70% 40% 20% 20% 20% 10% 10%

Pokegama 13 69% 69% 46% 38% 38% 38% 31% 8% 0%

Bear River Totals 171 49% 44% 35% 27% 22% 18% 19% 5% 5%



Table 7-5. Perceived vs Actual Presence of AIS in Lakes

% of Respondents Believing AIS is Present vs. AIS Actually Present, Yes (Y) or No (N)

Lake #

Respondents BMS EWM RS CMS FJ RC CLPW PL

Crawling Stone 33 18% N 9% N 9% Y 6% N 0% N 36% y 0% N 18% N

Little Trout 0 0% N 0% N 0% Y 0% N 0% N 0% y 0% N 0% N

Fence 43 16% N 16% N 19% Y 7% N 0% N 30% N 2% N 5% y

Long Interlaken 10 20% N 20% N 0% Y 10% N 0% N 0% N 0% N 0% N

Flambeau 10 30% N 10% N 10% Y 20% N 10% N 20% N 0% N 10% y

Moss 10 30% N 20% N 0% N 10% N 30% N 10% N 30% N 60% Y

Ike Walton 8 13% N 0% N 0% N 0% N 0% N 13% N 0% N 0% N

White Sand 34 6% N 9% N 0% N 6% N 3% y 15% y 3% N 21% y

Little Crawling Stone 10 10% N 20% N 0% Y 0% Y 0% N 50% y 0% N 20% N

Pokegama 13 15% N 15% N 15% Y 0% Y 8% N 23% y 23% N 15% N

Bear River Totals 171 16% 13% 8% 6% 4% 25% 5% 15%

BMS: Banded mystery snail CLPW: Curly-leaf Pondweed EWM: Eurasian Water Milfoil RS: Rainbow Smelt CMS: Chinese mystery snail FJ: Freshwater Jellyfish PL: Purple Loosestrife RC: Rusty Crayfish

Table 7-6. Percent of Residents Looking for AIS and Frequency

Lake #

Respondents Never Once per Season Monthly Weekly Daily

Crawling Stone 31 38.70% 29% 9.70% 9.70% 12.90%

Little Trout 0 0% 0% 0% 0% 0%

Fence 41 43.90% 29.30% 19.5 2.40% 4.90%

Long Interlaken 9 55.60% 22.20% 22.2 0% 0%

Flambeau 10 40% 30% 0% 10% 20%

Moss 10 10% 30% 50% 10% 0%

Ike Walton 7 57.10% 28.60% 14.30% 0% 0%

White Sand 32 37.50% 34.40% 21.90% 6.20% 0%

Little Crawling Stone 9 33.30% 11.10% 22.20% 33.30% 0%

Pokegama 12 58.30% 16.70% 16.70% 8.30% 0%

Bear River Totals 161 41% 28% 18.60% 7.50% 5%



Table 7-7. Residents Responding They Are Concerned About AIS

Lake # Respondents Extremely Concerned Somewhat Concerned Not Too Concerned Not Sure

Crawling Stone 33 36.40% 51.50% 3% 9%

Little Trout 0 0% 0% 0% 0%

Fence 42 52.40% 33.30% 4.80% 9.50%

Long Interlaken 9 33.30% 55.60% 11.10% 0%

Flambeau 9 33.30% 55.60% 11.10% 0%

Moss 10 20% 80% 0% 0%

Ike Walton 8 50% 25% 12.50% 12.50%

White Sand 34 58.80% 32.40% 2.90% 5.90%

Little Crawling Stone 9 100% 0% 0% 0%

Pokegama 13 46.20% 46.20% 0% 7.70%

Total Bear River 167 48.50% 40.70% 4.20% 6.60%



Notes for Section 7 1. Wayne Grady The Great Lakes: The Natural History of a

Changing Region (Greystone Press, 2007) 274.

2. Scott Gatzke is the writer and performer of the folk song called The Ballad of Aquatic Invasive Species. This song and other songs by different writers and performers, such as One Boat, One Lake and Clean Boats, Clean Waters, are available (and can be listened to ) through the University of Wisconsin Extension: http://www.uwex.edu/erc/music/song_ballad_of_aquatic.html.

3. Wisconsin Department of Natural Resources online: http://dnr.wi.gov/topic/Invasives/what.html.

4. Ibid.

5. Ibid. Also see A Statewide Strategic Plan for Invasive Species: Priority Objectives 2013-2016 (Wisconsin Department of Natural Resources, April 2, 2013) 6. Online at http://invasivespecies.wi.gov/docview.asp?docid=24479. Also see Aquatic Invasive Species Monitoring Procedures (Wisconsin Department of Natural Resources, UW-Extension and Wisconsin Association of Lakes, prepared by Laura Herman, March 2009) 3. This document is a guide for citizens interested in monitoring for aquatic invasive species. The manual provides much information on the impacts of AIS. Online at http://www4.uwsp.edu/cnr/uwexlakes/CLMN/publications.asp

6. For specific information on the costs, see Estimating the Cost of Invasive Species in Northern Highland Lakes, a study that revealed an annual welfare loss of approximately $1800 on average per shoreline property as determined by survey of 2,955 residents in 2008. The research is available at http://lter.limnology.wisc.edu/research/research_highlight/estimating-costs. Also, the costs associated with Aquatic Invasive Species are of national concern. For a review of the economic impacts of AIS nationwide, see Sabrina J. Lovell, Susan F. Stone, and Linda Fernandez, The Economic Impacts of Aquatic Invasive Species: A Review of the Literature (Northeastern Agricultural and Resource Economics Association, Agriculture & Economics Resource Review, 2006)195-208. And, the problems and issues related to Aquatic Invasive Species are not limited to the United States and Wisconsin. For an interesting perspective on AIS and globalization, see Reuben P. Keller, Invasive Species in Europe: Ecology, Status, and Policy (Environmental Science in Europe, a SpringerOpen Journal, 2011), online at http://www.enveurope.com/content/23/1/23.

7. Information provided in periodic updates from the Vilas County Invasive Species Coordinator.

8. Climate Change Adaptation Plan - Draft (Office of Water, United States Environmental Protection Agency, September 2013) 4. Online at: http://epa.gov/climatechange/Downloads/impacts-adaptation/office-of-water-plan.pdf. Also see Global Climate Change Impacts in the United States; U.S. Global Change Research Program (Cambridge University Press, 2009) 122. Online at: http://downloads.globalchange.gov/usimpacts/pdfs/climate-impacts-report.pdf.

9. Aquatic Invasive Species Monitoring Procedures, 155.

10. Ibid.

11. Ibid.

12. U.S. Geological Survey online: http://nas.er.usgs.gov/queries/factsheet.aspx?SpeciesID=1045 (4/4/2013, Page 3).

13. U.S. Geological Survey online: (4/4/2013, page 3). http://nas.er.usgs.gov/queries/factsheet.aspx?SpeciesID=1047


15. Ibid.

16. U.S. Geological Survey online: http://nas.er.usgs.gov/queries/factsheet.aspx?SpeciesID=1045. (4/4/2013, Page 3).


18. As recently as November 11, 2013, Chinese mystery snails were available for purchase at $3.00 through Aquatic Community at: http://www.aquaticcommunity.com/ads/search.php?searchid=14409.


20. Ibid.

21. Ibid.

22. Ibid.

23. Ibid.

24. Ibid.

25. Ibid, 48.

26. Ibid.

27. Ibid.

28. Ibid.

29. Ibid, 17.

30. Ibid.

31. Ibid.

32. Ibid.

33. Ibid.

34. Ibid.

35. Ibid.

36. Ibid, 18.

37. Ibid.

38. Ibid.

39. Ibid, 191.

40. Ibid.

41. Ibid.

42. Ibid.

43. Ibid.

44. Ibid.

45. Ibid, 192

46. Ibid.

47. Ibid.

48. Ibid.

49. Ibid.

50. Ibid, 105.

51. Ibid.

52. Ibid.

53. Ibid.

54. Ibid.

55. Ibid.

56. Ibid.

57. Ibid.

58. Wisconsin Department of Natural Resources. Online at: http://dnr.wi.gov/lakes/invasives/aisdetail.aspx?roiseq=22554562.



59. History of Smelt in the Great Lakes (University of Wisconsin Sea Grant Institute). Online at: http://www.seagrant.wisc.edu/Home/Topics/FishandFisheries/Details.aspx?PostID=360.

60. Ibid.

61. Wisconsin Department of Natural Resources. Online at: http://dnr.wi.gov/topic/invasives/documents/classification/lr_osmerus_mordax.pdf.

62. Combination of information from multiple sources, including: see footnotes 59 and 61; and, USGS at: http://nas.er.usgs.gov/queries/FactSheet.aspx?speciesID=796; and http://limnology.wisc.edu/personnel/jakevz/ais/rainbowsm

elt.html. 63. Wisconsin Department of Natural Resources, see

footnote 61.

64. Larry Wawronowicz, Director of Tribal Natural Resources Department. From a presentation made at a Lake Steward Workshop, August 4, 2010.

65. Wisconsin Department of Natural Resources, see footnote 61.

66. Aquatic Invasive Species Monitoring Procedures ,173.

67. Ibid.

68. Ibid.

69. Ibid.

70. Ibid.

71. Ibid.

72. Ibid.

73. Ibid.

74. Ibid.

75. Ibid, 174.

76. Ibid.

77. Reed Canary Grass Management Guide (Wisconsin Department of Natural Resources, PUB-FR-428 2000). Online at: at http://dnr.wi.gov/topic/forestmanagement/documents/pub/fr-428.pdf.

78. Through the Looking Glass, A Field Guide to Aquatic Plants (Reindl Printing, Inc., Merrill, WI., 2001) 48-49.

79. Reed Canary Grass Management Guide.

80. Ibid.

81. Ibid.

82. Fact sheet about the Yellow Iris provided by the Vilas County Land & Water Conservation Department, March 2013.

83. Wisconsin Department of Natural Resources. Online at: http://dnr.wi.gov/topic/invasives/fact/yellowflagiris.html.

84. Fact sheet about yellow iris, see footnote 82.

85. Ibid.

86. Wisconsin Department of Natural Resources, see footnote 83.

87. Fact sheet about yellow iris, see footnote 83.

88. Bear River Watershed Comprehensive Lake Management Plan Survey, Lake-by-lake Comparisons, 2012, See Appendix.

89. Ibid, Items 1, 2. See Appendix.

Figure Notes for Section 7 Figure 7-1. Chinese Mystery Snail. Photo from “Kemongsa Science In Picture” Volume 21, published by Kemongsa, 1993. http://www.in.gov/dnr/files/CHINESE_MYSTERY_S NAIL.pdf

Figure 7-2. Banded Mystery Snail. Amy Bensn, USGS. http://nas.er.usgs.gov/queries/factsheet.aspx?Speci esID=1047

Figure 7-3. Curly-Leaf Pondweed. Leslie J. Mehrhoff, University of Connecticut, http://www.mtweed.org/curlyleaf-pondweed/.

Figure 7-4. Infestation of Curly-Leaf Pondweed. Photo provided by Vilas County Invasive Species Coordinator. Raking curly-leaf pondweed from Little Saint Germain Lake in 2002.

Figure 7-5. Infestation of Curly-Leaf Pondweed. Little Saint Germain Lake, 2002. Photo provided by Vilas County Invasive Species Coordinator.

Figure 7-6. Turion of Curly-Leaf Pondweed. Robert W. Freckmann, Herbarium, University of Wisconsin, Stevens Point, http://www.mtweed.org/curlyleaf- pondweed/.

Figure 7-7. Comparison of EWM with the Native Northern Water Milfoil, Wisconsin Department of Natural Resources Wild Cards

Figure 7-8. Infestation of Eurasian Water Milfoil. Photo provided by Vilas County Invasive Species Coordinator.

Figure 7-9. Eurasian Water Milfoil Fragmention. EWM on Little Saint Germain Lake, 2002. Photo provided by Vilas County Invasive Species Coordinator.

Figure 7-10. Freshwater Jellyfish. Photo Open Cage Wikimedia Commons, http://newswatch.nationalgeographic.com/2012/08/3 1/freshwater-jellyfish-species-of-the-week/

Figure 7-11. Freshwater Jellyfish. Myriah Richerson, USGS/NAS, http://nas.er.usgs.gov/queries/FactSheet.aspx?speci esID=1068

Figure 7-12. Rusty Crayfish. Wisconsin Department of Natural Resources. http://dnr.wi.gov/org/caer/ce/eek/critter/invert/rustycr ayfish.htm

Figure 7-13. Rainbow Smelt, http://en.wikipedia.org/wiki/Rainbow_smelt

Figure 7-14. Rainbow Smelt, http://www.adirondackalmanack.com/2011/03/adiron dack-fish-rainbow-smelt.html

Figure 7-15. Spiny and Fishhook Waterfleas, Sea Grant Minnesota http://www.seagrant.umn.edu/ais/waterflea

Figure 7-16. Spiny Waterfleas on fishing line. Sea Grant Minnesota http://www.seagrant.umn.edu/ais/waterflea

Figure 7-17. Infestation of Reed Canary Grass. Minnesota Department of Natural Resources, Photo by Angela Anderson. http://www.dnr.state.mn.us/invasives/terrestrialplant s/grasses/reedcanarygrass.html

Figure 7-18. Yellow Flag Iris. Noxious Weed Control Board. http://www.nwcb.wa.gov/detail.asp?weed=78



Figure 7-19. Purple Loosestrife. Maryland Department of Natural Resources, Photo by K.L. Kyde. http://dnr.maryland.gov/wildlife/Plants_Wildlife/Purpl eLoosestrife/index.asp

Table Notes for Section 7 Table 7-1. Presence of AIS Near or In Lac du Flambeau.

Table 7-2. Aquatic Invasive Species in Lac du Flambeau.

Table 7-3. Prior Knowledge of AIS. Data from Bear River Watershed Comprehensive Lake Management Plan Survey, Lake-by-lake Comparisons, June 2012, Question #25. See Appendix.

Table 7-4. Lake resident Survey on Lakes Perceived to be Threatened by AIS. Data from Bear River Comprehensive Lake Management Plan Survey, Lake-by-lake Comparisons, June 2012, Question #27. See Appendix.

Table 7-5. Perceived vs Actual Presence of AIS in Lakes. Bear River Watershed Comprehensive Lake Management Plan Survey, Lake-by-lake Comparisons, June 2012, Question #26. See Appendix.

Table 7-6. Percent of Residents Looking for AIS and Frequency. Bear River Watershed Comprehensive Lake Management Plan Survey, Lake-by-lake Comparisons, Question #28. See Appendix.

Table 7-7. Residents Responding They Are Concerned About AIS. Bear River Watershed Comprehensive Lake Management Plan Survey, Lake-by-Lake Comparisons, Question #29. See Appendix.

Figures Figure 7-1. Chinese Mystery Snail .................................... 7-3

Figure 7-2. Banded Mystery Snail ..................................... 7-3

Figure 7-3. Curly-Leaf Pondweed ..................................... 7-4

Figure 7-4. Infestation of Curly-Leaf Pondweed ................ 7-4

Figure 7-5. Infestation of Curly-Leaf Pondweed ................ 7-4

Figure 7-6. Turion of Curly-Leaf Pondweed ...................... 7-5

Figure 7-7. Comparison of EWM with the Native Northern Water Milfoil ............................................ 7-5

Figure 7-8. Infestation of Eurasian Water Milfoil ................ 7-6

Figure 7-9. Eurasian Water Milfoil Fragmentation ............. 7-6

Figure 7-10. Freshwater Jellyfish ...................................... 7-6

Figure 7-11. Freshwater Jellyfish ...................................... 7-7

Figure 7-12. Rusty Crayfish .............................................. 7-8

Figure 7-13. Rainbow Smelt .............................................. 7-8

Figure 7-14. Rainbow Smelt .............................................. 7-9

Figure 7-15. Spiny and Fishhook Waterfleas .................. 7-10

Figure 7-16. Spiny Waterfleas on Fishing Line ................ 7-10

Figure 7-17. Infestation of Reed Canary Grass ............... 7-11

Figure 7-18. Yellow Flag Iris ........................................... 7-11

Figure 7-19. Purple Loosestrife ....................................... 7-12

Tables Table 7-1. Presence of AIS Near or in Lac du

Flambeau* ............................................................. 7-1

Table 7-2. Aquatic Invasive Species in Lac du Flambeau Lakes* ................................................... 7-2

Table 7-3. Prior Knowledge of AIS .................................. 7-12

Table 7-4. Lake Resident Survey on Lakes Perceived to be Threatened by AIS ...................................... 7-13

Table 7-5. Perceived vs Actual Presence of AIS in Lakes ................................................................... 7-14

Table 7-6. Percent of Residents Looking for AIS and Frequency ............................................................ 7-14

Table 7-7. Residents Responding They Are Concerned About AIS ............................................................. 7-15

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