Silent Invaders: Biodiversity Decline as a Result of Zebra and quagga Mussel Over Population
A Historical Study of Eurasian Mussels in the North Country and
Preventing their Spread Out West
Madelyn T. Gilroy
Carlie A. Wright
Biology Department
St. Lawrence University
23 Romoda Drive
Canton, NY 13617
Photo Credit:
http://media.jrn.com/images/b99289167z.1_20140611224929_000_gnu6jrdv.1-1.jpg
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TABLE OF CONTENTS
LIST OF TABLES AND FIGURES............................................................................................ 7 EXECUTIVE SUMMARY .......................................................................................................... 8 INTRODUCTION ...................................................................................................................... 11 METHODS .................................................................................................................................. 20 INTERVIEW SUBJECTS ............................................................................................................................................................ 20 PROBLEM DEFINITION ......................................................................................................... 22 BALLAST WATER: ................................................................................................................................................................... 22 BIOLOGY OF ZEBRA MUSSELS AND QUAGGA MUSSELS .................................................................................................... 23 BIODIVERSITY IMPACTS: ....................................................................................................................................................... 26 Algal Blooms ......................................................................................................................................................................... 26 Outcompeting Native Mussels: ..................................................................................................................................... 28 Diets .......................................................................................................................................................................................... 30 HUMAN IMPACTS ON BIODIVERSITY LOSS: ........................................................................................................................ 31 IDENTIFICATION OF STAKEHOLDERS............................................................................ 34 RESIDENTS: .............................................................................................................................................................................. 34 RECREATION INDUSTRY: ....................................................................................................................................................... 36 GOVERNMENT OFFICIALS: .................................................................................................................................................... 37 COMMERCIAL WATER INDUSTRIES: .................................................................................................................................... 38 Hydro-­‐Electrical industries: ........................................................................................................................................... 38 Water industries (municipal supplies): .................................................................................................................... 40 INVASIVE SPECIES SCIENTISTS: ............................................................................................................................................ 40 WATER-­‐ TRANSPORTATION INDUSTRY: ............................................................................................................................ 41 iii
GOVERNMENTAL ISSUES..................................................................................................... 43 BALLAST WATER REGULATIONS ......................................................................................................................................... 44 CLEAN BOATING ACT ............................................................................................................................................................. 45 ECONOMICS: ............................................................................................................................................................................. 46 RECREATION RESTRICTION .................................................................................................................................................. 47 DEVELOPMENT OF SOLUTIONS TO THE PROBLEM ................................................... 48 PARAMETERIZING SOLUTIONS .............................................................................................................................................. 48 NORTH COUNTRY FAILURES ................................................................................................................................................. 48 IDENTIFICATION AND EVALUATION OF POTENTIAL SOLUTIONS .................................................................................... 50 Zequanox (Closed System Solution): .......................................................................................................................... 50 Open-­‐system solution: ...................................................................................................................................................... 51 Potassium Chloride: ........................................................................................................................................................... 52 Zebra mussel traps: ........................................................................................................................................................... 52 Introduce the predator the Black Carp: ................................................................................................................... 53 Boat Cleaning: ...................................................................................................................................................................... 53 Ballast Water Regulations: ............................................................................................................................................ 54 Education: .............................................................................................................................................................................. 55 IDENTIFICATION OF FEASIBLE SOLUTIONS: ........................................................................................................................ 55 Potassium Chloride “Potash”: ........................................................................................................................................ 55 Zequanox: ............................................................................................................................................................................... 56 Zebra mussel traps: ........................................................................................................................................................... 56 Boat Cleaning: ...................................................................................................................................................................... 56 Education: .............................................................................................................................................................................. 56 Ballast Water Treatment: ............................................................................................................................................... 57 iv
IDENTIFICATION OF BEST SOLUTIONS ................................................................................................................................ 57 EASE OF IMPLEMENTATION .............................................................................................. 59 ZEQUANOX ............................................................................................................................................................................... 59 BOAT CLEANING ..................................................................................................................................................................... 59 EDUCATION .............................................................................................................................................................................. 60 IMPLEMENTATION PLAN .................................................................................................... 61 CONCLUSIONS ......................................................................................................................... 63 ACKNOWLEDGEMENTS ....................................................................................................... 65 LITERATURE CITED .............................................................................................................. 67 Karatayev A, Burlakova L, Mastitsky S, Padilla D. 2015. Predicting the spread of aquatic invaders: insight from 200 years of invasion by zebra mussels. Ecological Applications 25(2): 330-­‐340 ...... 69 TABLE AND FIGURE CITATIONS ....................................................................................... 74 APPENDICES ............................................................................................................................. 75 APPENDIX A: INTERVIEW QUESTIONS ................................................................................................................................ 75 v
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LIST OF TABLES AND FIGURES
Figure 1: Concept map of Zebra and quagga mussel invasion…………………………...8
Figure 2. Zebra Mussel invasion in the Great Lakes System…………..…………………9
Figure 3. Distinction between Zebra and quagga mussels………………………………10
Figure 4. Calcium levels throughout the United States and established zebra and quagga
mussel populations (Whittier et al 2008)………………………………………………...11
Figure 5. Lake Champlain food web…………………………………………………......14
Figure 6. USGS calculated populations of zebra and quagga mussels…………………..16
Figure 7. Invasive species curve…………………………………………………………15
Figure 8. Life cycle stages for Zebra and quagga mussels………………………………21
Figure 9. Food web showing the effects of zebra mussels on nutrient cycling……..…...22
Figure 10. Phosphorous levels in Lake Champlain……………........…………………...24
Figure 11. Zebra and quagga mussels clogging pipes…………………………………...39
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EXECUTIVE SUMMARY
For nearly two decades biodiversity in the North Country in Northern NY has been
threatened by zebra mussels (Dreissena polymorpha) and quagga mussels (Dreissena bugensis),
here forth referred to together as Eurasian mussels. These invasive Eurasian mussels were first
introduced into the Great Lakes in the late 1980s before making their way to the St. Lawrence
River in 1991. Since 1991, these Eurasian mussels have been wreaking havoc on our most
treasured water bodies. In this report, we are focusing on the introduction of Eurasian mussels
into the St. Lawrence River, Lake Champlain and a couple of the Great Lakes (specifically Lake
Erie and Lake Ontario). These water bodies have seen dramatic changes over the last two
decades as a result of increasing Eurasian mussel populations, including changes in ecosystem
composition.
Eurasian mussels are filter feeders consuming the tiniest organisms, phytoplankton, in
water bodies. At first glance, this would appear to be beneficial. Clearer water means greater
recreational use of the lake, however clearer water also means that the composition of the lake
ecosystem is changing. By decreasing phytoplankton levels, Eurasian mussels will be
responsible for decreasing zooplankton and planktivorous fish stocks as well (Colvin et al.
2015). Eurasian mussels do not eat blue-green algae; also known as cyanobacteria, when filter
feeding. The increase in blue-green algae therefore increases the algal blooms on our lakes and
rivers (Stallard 2015). These algal blooms release toxins into the water that create a lower pH.
This increase in acidity and toxicity can kill native fish species living in the water body. Native
mussels are also at risk of decreasing because Eurasian mussels will outcompete their food
source and suffocate native mussels by using them as a hard surface to grab on to with their
byssal threads (Colvin et al. 2015).
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Along with biodiversity loss there comes a great economic, social and governmental
price to controlling Eurasian mussels. The US government has spent upwards of 5 billion dollars
trying to control the species since its first introduction into North America in the late 1980s
(USGS 2016). For the last decade, the Federal government and New York State government
have been working hard to prevent the future introduction of invasive species into shipping ports
on the east coast by increasing ballast water regulations. The government at a federal level in the
United States has also passed regulations entitled The Invasive Species Act as well as the Clean
Boating Act, which together work towards decreasing the likelihood of spread and establishment
of Eurasian mussels and other invasive species into water bodies throughout the United States.
As we have seen throughout our research, there is no fix all solution when it comes to
controlling Eurasian mussels from spreading. The increased use of a the pesticide Zequanox,
along with prevention education and maintaining strict ballast water regulations across the
country remain the best ways in which the Eurasian mussels can be controlled. There have been
many failed prevention and eradication techniques in the North Country, as this is where the
introduction first occurred. However, the purpose of this paper is to recognize these failures and
to stress the importance of prevention education on the West Coast. The less the Eurasian
mussels spread the less damage they will be able to do to the lakes and rivers across the continent
(Figure 1). The North Country may no longer be at a place where eradication is feasible,
however with the proper control mechanisms the population of Eurasian mussels can at least be
slowed down and will have less effects on biodiversity in our lakes and rivers.
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Figure 1. Concept Map of zebra and quagga mussel invasion into the United
States.
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INTRODUCTION
Zebra mussels (Dreissena polymorpha) and quagga mussels (Dreissena bugensis)
originated in the Caspian Sea near northern Iran and Russia (nps.gov 2016). In the 1700s they
migrated to Europe through popular trade routes by hitchhiking a ride on large cargo ships.
These Eurasian mussels were transported through ballast water. When shipping vessels were
leaving Iran and Russia to pick up goods in Europe they balanced the ship by using ballast water
from the Caspian Sea. Once arriving in port the water would be removed as the cargo was loaded,
releasing hitchhiking larvae into European waters (Karatayev et al. 2015). Once established in
Europe it took over a hundred years for Zebra mussels to migrate to North America despite
continuous trade. One reason for this stall in expansion was, that up until the 1900s solid ballast
was used for North American shipping, which decreased the transport of aquatic organisms
(O’Neill 1994).
Zebra and quagga mussels are freshwater organisms and can only withstand salinity
levels up to 3ppt (O’Neill 1994). The average salinity levels between Europe and the Americas is
about 25 ppt making it impossible for these invasive mussels to travel on the outside of the ship
(Gilroy 2015). This life history characteristic decreased the likelihood of Zebra and quagga
mussels becoming established in North America. It wasn’t until 1959 when the St. Lawrence
Seaway was constructed connecting the Great Lakes to the open ocean through a system of locks
and canals that the likelihood of these mussel becoming established increased (Sussman 1978).
From that point on oceangoing vessels were transporting cargo to lake ports where salinity levels
would be suitable for Zebra and quagga mussels and realizing their ballast.
In June of 1988 Zebra mussels’ populations reached noticeable numbers and were
discovered in Lake St. Clair near Detroit, Michigan. Due to Lake St. Clair’s proximity to the
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Great Lake system (Figure 2) it was only four months before Zebra mussels were discovered in
Lake Erie and by the start of the 1990s they were established throughout the Great Lake systems
(O’Neill 1994).
Figure 2. Great Lakes System once affected by Zebra and quagga mussels.
Zebra mussels quickly spread to interior lakes like Lake Champlain in 1993 and were
fully established in the Mississippi river basin around the same time (NWF 2016). This is due to
their unique characteristic that allows Zebra mussels to attach to hard surfaces, like recreational
vessels allowing access to other freshwater systems (Karatayev et al. 2015). This characteristic
which is often associated with saltwater mussels is not seen in any other freshwater bivalve in the
Northern Hemisphere, aside from the Quagga mussel (figure 3)(USGS 2016).
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Figure 3. Differences between Zebra and quagga mussels
The Quagga mussel was first sighted in Lake Erie in 1989 and due to being almost
behaviorally identical to the Zebra mussel it wasn’t until 1991 that they were recognized as
separate species (Colvin et al. 2015). The two major differences between these two invasive
Eurasian mussels are that the Quagga mussel does not have stripes and are also known for
occupying deeper colder water, which allows them greater niche recognition potential (Colvin et
al. 2015). Zebra and quagga mussels are almost always researched together and pose the same
threats to invade ecosystems.
These invasive Eurasian mussels are now present in 29 U.S states and 3 Canadian
provinces, due to vessels movement from invaded waterways (USGS 2016). Water composition
has been the only preventive force limiting Zebra and quagga mussels’ expansion. Due to the
lack of calcium ions needed for shell growth, waterbodies with soft water are at low risk for
invasion (Figure 4) (Whittier et al 2008). Soft water, is water with low ion content due to the
absence of dissolved salts that combine with metals like calcium and magnesium (Soft water
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2016). This physical limitation can explain why the St. Lawrence River and Lake Champlain
have been Invaded and neighboring water bodies like in the Adirondack have been unaffected by
Zebra mussels (Whittier et al 2008).
Figure 4. Calcium levels throughout the United States and states at high risk of
invasion (Whittier et al. 2008).
What has made Zebra and quagga mussels a topic for conservation concern is their
invasive characteristics and their ability to destroy a native ecosystem. Due to their fast
population growth and lack of predators, they can outcompete native species, which results in a
disruption in the local food web (Figure 5) (Karatayev et al. 2015). Zebra and quagga mussels
have been known as one of the most aggressive aquatic invasive species, due to their size these
mussels can go undetected until population size is too large to eradicate or control (O’Neill
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1994). Zebra and quagga mussels are able to expand their population and area rapidly upon
invasion due to their planktonic larval stage and ability to reproduce quickly (Karatayev et al.
2015). A female Zebra mussel can produce one million eggs a year (Kaufmann 2012).
Zebra and quagga mussels’ effect on native biodiversity can be seen throughout the food
web resulting from a bottom up control model (Karatayev et al. 2015). These Eurasian mussel
decrease native mussel diversity and other filter feeding fish by outcompeting them for food and
space. Through the reduction of native mussels, predatory molluscivores higher up on the food
web are being impacted due to the lack of food and the Eurasian mussels are an inefficient food
source. Predatory fish populations are also impacted by these invasive Eurasian mussels due to
the absence of population control, which has led to the over consumption of zooplankton (Colvin
et al. 2015). Fish and mussels spend their larval stage as plankton and with increased
consumption many fish populations higher up on the food web who have adapted lower fecund
are being greatly affected. Many of those larger predatory fish are already experiencing pressure
from fishing and this added stress from the bottom of the trophic system has potential to collapse
the entire aquatic ecosystem.
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Figure 5. Food web of Lake Champlain.
Over the past two decades, researchers have developed extensive knowledge on these
invasive mussels. Several possible control mechanisms have been put in place over the last
several years. However nothing seems to be slowing this invasive species problem in the North
Country. What has been seen in the North Country is that people have started accepting Zebra
and quagga mussels as a part of the ecosystem, and have decreased efforts on eradication.
Instead most stakeholders have developed a system of maintenance management seen in the
commercial water and recreation industry giving up hope on restoring the ecosystems
biodiversity.
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Figure 6. Zebra and quagga mussels’ distribution in North America as of March
30th 2016 (USGS 2016)
Due to the decreased eradication effort the invasive Zebra and quagga mussels are not
publicly seen as a problem in the North Country anymore. However, as long as waterbodies in
the North Country are invaded these invasive Eurasian mussels will continue to impact
biodiversity the same today as they have been for the last two decades (Figure 5).
The United States is a country connected by watersheds making the transfer of zebra and quagga
mussels likely to occur continually. Currently the west coast is a decade behind the Northeast on
the Eurasian mussel invasion and if implemented correctly could use knowledge and products
already developed to fight and prevent invasion. The Northeast has been at the forefront for
Zebra and quagga mussel research and developed products like ballast water filtration treatment
systems and Zequanox (refer to solutions section for more information) to reduce environmental
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costs of this invasive. What makes the West Coast so vulnerable to this invasive mussel issue is
the high calcium concentrations (Figure 4), and how connected their waterways are (much like
the Mississippi river basin). Due to the high risk of invasion it is extremely important this issue is
addressed before it is too late. One aspect of this case study is to determine the importance of
prevention and awareness when it comes to invasive species (Figure 7). The sooner the public
becomes aware the easier it will be to eradicate the populations that have been established.
Figure 7. Invasive Species Curve
This case study will examine how biodiversity has declined as a result of the Zebra and
quagga mussel overpopulation over the past 2 decades as well as consider some possible
solutions for eradication and population control. Throughout this paper we will define ways in
which the West Coast of the United States can prevent the same catastrophic event from
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happening to them that we have observed in the North Country. We will do this by identifying
the stakeholders (residents, recreational users, government officials, hydro-electrical industry,
transportation, and scientists) and researching the problems they have had as a result of this
invasion. The seven goals of this case study are:
1. Summarize the history of invasion in the Northeast.
2. Determine what has been done to eradicate or control the species.
3. Determine the most effective and sustainable methods of population control/ eradication.
4. Show the power of how invasives can change an ecosystem
5. Describe the ways Zebra Mussels impact humans
6. Determine the economic cost of controlling or eradicating Zebra Mussel
7. Show how this problem can be prevented with early detection and interception.
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METHODS
To conduct our case, we directed our research towards Lake Champlain, the St. Lawrence
River and a couple of the Great Lakes (specifically Lake Erie and Lake Ontario) (Figure 2). To
gather information we looked at primary scientific journals, newspaper articles, YouTube videos,
documentaries and podcast. Each type of resource provided us with a different perspective on the
topic, whether that be the science behind Eurasian mussels and the destruction they cause
environmentally or the social impacts that they are having on the surrounding human
populations.
We also conducted a series of interviews in the month of March 2016. These interviews
were with people whom are experts on their topic and also people that we found could supply us
with extra information on what we were finding through the literature. Interview questions can
be found in appendix A. E Draw max was used to create the concept map (Figure 1) for this case
study.
Interview Subjects
Dr. Brad Baldwin: Dr. Baldwin is a Professor of Biology at St. Lawrence University who
has experience researching Eurasian mussels in the North Country. His interview gave us a better
view as to what the problem is specifically near St. Lawrence County. His interview also gave us
an interesting perspective as to why the Adirondacks have not (yet) been infiltrated by Eurasian
mussels in some of the larger lakes and rivers.
Anastasia Burdock: An important aspect of this case study is understanding the
residential opinion. Mrs. Burdock supplied us with the understanding of how Eurasian mussels
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have impacted her recreational use of Lake Champlain, including impacts such as cutting her
feet, using her boat, and having to follow strict regulations on cleaning her boat after use.
Larry Eichler: Mr. Eichler is a research scientist at Rensselaer Polytechnic Institute
specifically working with the Darrin Freshwater Institute on Lake George. Though we did not
specifically look at Lake George in our case study, Mr. Eichler was able to provide us with ways
in which Eurasian mussels have affected inland lakes, as it is not just an issue at shipping ports.
Dr. Daniel P. Malloy: Dr. Molloy is an Adjunct Professor of Biology at the University of
Albany and has worked on Eurasian mussel overpopulation since their first introduction in the
late 1980s. His field of expertise is controlling the species specifically with his own solution,
Zequanox. Zequanox is a useful solution to the problem of Eurasian mussel overpopulation, but
later we discuss why it has yet to be widely used. Dr. Molloy’s interview gave us a better grasp
of what has actually been done in order to keep the Eurasian mussel population under control
throughout the last couple of decades.
Ted Snieckus: Mr. Snieckus is a US Naval Third Mate who specializes in large cargo
ship transportation. His interview was critical in understanding the rules and regulations that
cargo ships have to undergo in order to exchange ballast water (a known contributor to the
invasive problem) and other aspects of how Eurasian mussel overpopulation has impacted
transportation in and out of the United States.
Each of these interviews provided us with an opinion and knowledge that we would
otherwise have been unable to find in the literature.
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PROBLEM DEFINITION
Ballast Water:
Ballast water is water that is taken on by a vessel to compensate for changes in the
vessel’s weight as cargo is loaded or unloaded, and as fuel supplies are consumed. On a global
scale, commercial shipping transports approximately 2/3 of world trade based on tonnage and
requires the discharge of 3.5 billion tons of ballast water each year (Stallard 2015). When a
vessel takes on ballast water, whether freshwater or saltwater, organisms found in that water are
typically taken on as well. These organisms, often referred to as aquatic nuisance species, are
carried in the ballast tanks of vessels until the vessel arrives at its next port where, due to
changes in distribution of the vessel’s cargo, the organisms may be realized into a new
ecosystem, establish viable populations, and prey on or outcompete indigenous species (Stallard
2015). Examples of invasive species that have been introduced into New England though ballast
water include, zebra and quagga mussels, shipworms and green crab. These species were all
introduced before the United States placed stricter regulations on ballast water, those regulations
currently stating that ballast water exchange must occurring no closer than 200 nautical miles
from the shoreline in water depths no less than 2000 m (Snieckus, personal communication)1.
The ships as a whole are not regularly cleaned. The inside tanks are cleaned periodically
but externally, the hull is all that is really cleaned on the ship. The hull needs to be cleaned in
order to keep the boat moving quickly and efficiently through the water, yet the rest of the
exterior of the ship is often ignored (Snieckus, personal communication)2. These before
1
Ted Snieckus, Email Interview 15 March, 2016
2
Ted Snieckus, Email Interview 15 March, 2016
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mentioned ballast water regulations included vessels to update their ballast water tanks to make
them easier to clean (Tuxil 2016), however many boats were given extensions on updating their
systems because of cost of doing so. By not all shipping vessels being able to update their ballast
water tanks to regulation standards, there is still potential for invasive species to still be
transported into new territory, like the Eurasian mussels.
Biology of Zebra Mussels and Quagga Mussels
These Eurasian mussels belong to the kingdom Animalia, phylum Mollusca and class
bivalvia. Zebra and quagga mussels are benthic filter feeders, using siphons; Eurasian mussels
filter food particles from water. (Colvin et al. 2015). Average-sized adult Eurasian mussels filter
about 1.5L of water a day, resulting in rather clear water systems. Eurasian mussels are picky
eaters, consuming only the best phytoplankton and leaving phytoplankton exposed to
cyanobacteria out of their diet (Mayer et al. 2001). The mussels themselves are not large,
reaching only the 5 mm or more commonly the size of a thumbnail in their adult form (Meyer et
al. 2001). Overpopulation of these Eurasian mussels have been the major cause for concern with
biodiversity decline in North Country lakes and rivers. Zebra mussels alone have a fecundity one
million eggs per adult female per year (Griffiths et al. 2011). Eurasian mussels live between 3
and 5 years.
Important to keep in mind throughout this case study is the life cycle of both quagga and
zebra mussels. There are three main periods in the zebra mussel life cycle: the larval, juvenile,
and adult stages (Figure 8). The larvae are planktonic (float in water column) during their initial
three life stages: trochophore, straight-hinged veliger, and umbonal veliger. Larvae eventually
settle on a substrate during their pediveliger stage, and move only by crawling during their
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plantigrade stage. The pediveliger is considered by some to be the final larval form, with the
plantigrade as a stage between larval and juvenile stages (Colvin et al. 2015).
Figure 8 Life cycle stages for zebra and quagga mussels.
Eurasian mussels have traditionally preferred cooler water temperatures, making them a
nuisance in the North Country. However, as the mussels spread out west they have been adapting
to warmer temperatures (Griffiths et al. 2011). Eurasian mussels tend to enjoy water
temperatures hovering around 28°C, anything much warmer and the mussels will begin to die
(USGS, 2016). As the Eurasian mussels have begun to move out west they have begun to adapt
to the warmer water. This spread into warmer water jeopardizes a large portion of the country
after their North Country invasion. As the mussels move west into California it is also a major
risk that they will also move south.
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Quagga mussels and zebra mussels have a similar biology in terms of their life cycle and
their eating patterns. Both of these mussels remove phytoplankton as noted by 80% and
subsequently also decrease zooplankton by 71%, these decreases dramatically alter the food web
in our lakes and rivers (Figure 9). Quagga mussels accumulate organic pollutants within their
tissues to levels more than 300,000 times greater than concentrations in the environment and
these pollutants are found in their pseudo feces. Pseudo feces is everything that the mussels
cannot consume for their health. These pollutants will be accumulated up the food chain as fowl
eat the zebra mussels, especially migratory birds (Snyder et al. 1997).
Figure 9. Food web showing nutrient cycling done by zebra and quagga mussels.
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In North America, Eurasian mussels have limited predators. It is seen that migratory birds
and diving ducks will actually eat the mussels but not at a rate that will maintain their
populations (Boyle 2015). When populations get out of control it is found that any hard surface
in the lake or river (including the floor of the water body) can be covered with upwards of 2
inches worth of these Eurasian mussels (Boyle 2015). By covering surfaces the mussels will not
only outcompete native mussel species but also cause blockages in pipes along waterfront
industry. Without enough natural predators, a high fecundity and the ability to glue themselves to
surfaces along with being a vector for organic pollutants, Eurasian mussels have had detrimental
effects on biodiversity within the North Country and are expected to continue this invasion as the
mussels move out west.
Biodiversity Impacts:
Algal Blooms
As Eurasian mussels do not consume blue-green algae (cyanobacteria) while filter
feeding, harmful toxins are accumulated into the water (Stallard 2015). Algal blooms in NYS
have always been an issue due to agricultural runoff, however with the overpopulation of
Eurasian mussels these algal blooms have nearly doubled in frequency (Stallard 2015) (Figure
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10).
Figure 10. Phosphorous increases in Lake Champlain.
Selective filtration by Eurasian mussels is responsible for lake-wide increases in
Microcytic and may also be a partial explain for the long-term decline in Anabaena, because this
genus does not form large colonies. The change in algae represented in Lake Erie is echoed in
Lake Champlain and similar water bodies (Connerton et al. 2006). Algal blooms can consume
dissolved oxygen from the lake resulting in large fish kills in the affected area (Higgins and
Zanden 2011). There has not been enough research done on the local North Country waterways
to determine the actual effects of these algal blooms as of 2016 but rather expected results,
including greater water toxicity and a lower pH. As the water becomes more inhabitable there
will be a decrease in small and large fish alike, especially if the pH falls below 5 (Higgins and
Zanden 2011).
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It is believed that beds of the invasive quagga and zebra mussels that are now common in
the Great Lakes provide a medium in which the cyanobacteria thrive. When fish, especially
another invasive species, the round goby, feed on the mussels, they take up the bacteria and its
neurotoxin. If birds consume those fish, the toxin poisons the birds. They typically are paralyzed
and drown in the water (Orr 2015). In order for the lakes to be properly monitored for these algal
blooms for the prevention of biodiversity loss of fish and fowl, the lakes need to be shut down
from recreational use. Cyanobacteria can be consumed up the food chain leading to
bioaccumulation, threatening the larger species that residents of the lakes and rivers have grown
fond of. Bioaccumulation starting with the smallest of organisms, like the zebra mussels, will
lead to greater issues higher up the trophic cascade and increase mortality of larger planktivorous
fish and predators to the Eurasian mussels.
Outcompeting Native Mussels:
Freshwater mussels (Order Unionoida) are the most imperiled faunal group in North
America; 60% of described species are considered endangered or threatened, and 12% are
presumed extinct (Ricciardi et al 1996). Eurasian mussels have outcompeted 8 of 14 total native
mussels in the Lake Champlain basin (Benson 2015). Eurasian mussels will decrease
phytoplankton stalks, outcompeting a food resource, and they will suffocate the native mussels
while competing for hard surfaces to establish themselves on. Giant Floater (Pyganodon
grandis), Pocketbook (Lampsilis ovata), Pink Heelsplitter (Potamilus alatus), Fragile Papershell
(Leptodea fragilis), Black Sandshell (Ligumia recta) are 5 of the 8 critically endangered native
mussels in the Lake Champlain basin. In the St. Lawrence River mussels belonging to the
families Unionidae and Margaritiferidae are amongst the highest risk for being outcompeted by
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Eurasian mussels. Eurasian mussels will attach themselves to the shells of native mussels,
suffocating them (Benson 2015). This means that native mussels will be covered so heavily with
zebra mussels that the native mussels will no longer be able to breath. 74% of unionids had been
colonized by zebra mussels in the St. Lawrence River, meaning that for every unionid there were
3.1 zebra mussels. By 1996, unionids had decreased by 52% as a result of increased zebra mussel
population (Ricciardi et al. 1996). Mortality amongst native species in the St. Lawrence River
will see heavy mortality (>90%) when the mass of Eurasian mussels cover the native mussels’
shells is equal to their own mass or greater (Ricciardi et al. 1996). Eurasian mussels will continue
to move throughout the country increasing the risk for native mussels to fall victim to suffocation
and starvation.
As Eurasian mussels began to outcompete mussels for food resources, native mussels in
the St. Lawrence River and the Hudson River declined in body mass by 34% (Strayer and
Malcom 2007). This change in the species was caused by a decrease in available food resources
for the native mussels and in turn the native mussels had to evolve to being smaller than they
were originally. However in the Hudson River, native mussels have made an interesting
recovery. The apparent recovery of Hudson River bivalves is consistent with observations of
coexistence of unionids and zebra mussels in European waters that were invaded by zebra
mussels decades to centuries ago (Strayer and Malcom 2007). The zebra mussels outcompeted
the native mussels originally declining their populations to near zero, however once the mussels
evolved to be smaller the native mussels were able to make a comeback.
Native mussels are not only impacted directly by the decrease in phytoplankton and the
need for food resources but they are also impacted indirectly. Native mussels have an extra step
in their life cycle that includes a parasitic stage (Mackel 1991). This stage is completed through
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the use of planktivorous fish, like the yellow perch. With a decrease in phytoplankton and food
availability leading to a decrease in these planktivorous fish numbers, it will be more difficult for
native mussels to complete their life cycle. Therefore, native mussels will be indirectly
negatively affected by the increase in Eurasian mussels and decrease in phytoplankton as well.
Diets
There are several small invertebrates living in water bodies that are often forgotten about.
These invertebrates include rotifers, protozoans and nauplii, all of which depend on
phytoplankton as a food resource. Rotifers are an aquatic organism belonging to the phylum
Rotifera, protozoans are single celled organisms belonging to the phylum protista and a nauplis
is the first larval stage of many crustaceans. These microscopic organisms depend on
phytoplankton in order to survive and thrive. Sometimes however, these little animals are acting
as food resources themselves for Eurasian mussels. One study done on Lake Champlain
concluded that rotifer decline was due to direct consumption by zebra mussels rather than
through starvation due to lack of phytoplankton (Miller et al. 2007). By consuming more
phytoplankton, there has been an increase in Eurasian watermilfoil, a seaweed plant, due to the
greater amount of sunlight that can be received with less phytoplankton. Therefore there is a new
composition in Lake Champlain in terms of plant species. Eurasian watermilfoil is also an
invasive plant to Lake Champlain known to (similarly as Eurasian mussels) outcompete native
plants (VPR Interview with Mary Watson, 2012). Eurasian watermilfoil is not as preferred by
foragers and waterfowl because it is less valuable as a food resource (VPR Interview, 2012).
Eurasian mussels consume phytoplankton in large quantities as well as the larval stage of
many invertebrates. There was a pronounced decline (~46%) in phytoplankton bio volume in the
St. Lawrence River stocked with Dreissena relative to a reference river lacking mussels
30
(Ricciardi et al. 1996). Nauplii, baby crustaceans, are often small enough to be consumed by the
Eurasian mussels (Miller et al. 2007). This will lead to fewer of the juveniles reaching adulthood.
Sometimes however, the larval stages are too big and escape filtration yet these larvae come to
be injured in the process. Injuries in the larval stage lead to higher mortality and are therefore
decreasing chances of making it to adulthood (Miller et al. 2007). A pattern that can be seen with
Eurasian mussels is that their small impacts on phytoplankton and zooplankton leads to a major
decline higher up the trophic cascade. Eurasian mussels were able to go undetected in North
Country water bodies for a couple years because they had not affected the larger fish species yet.
As the population of Eurasian mussels increased and phytoplankton decreased, there was a clear
shift in nutrient cycling leading to greater phosphorous levels. As phosphorous levels rose, there
was little available oxygen for larger fish species that created a decline (Higgens and Zandend
2011). In the St. Lawrence River, studies suggest that overlapping diets with mussels will
adversely affect growth and perhaps survival of planktivorous life stages of fish through direct
competition for the rotifers that are dietary important for many larval fish, and indirect
suppression of the phytoplankton which supports many zooplankton species (Thorp and Casper
2003). Yellow perch in its earlier life stages depend on zooplankton and phytoplankton for
survival. With an increase in Eurasian mussels leading to a decrease in phytoplankton, it is seen
that the perch will decrease as well (Thorp and Casper 2003).
Human Impacts on Biodiversity Loss:
Globalization has been occurring for centuries. This means that large cargo ships must be
used to transport goods throughout the world. Nonnative species, like zebra mussels and quagga
mussels, can be introduced into a country via supply ships. However, the likelihood of the nonnative species establishing and becoming a pest are 1/1000. Eurasian mussels were that .001%
31
after being introduced via the cargo ship’s ballast water tanks in the late 1980s. Yet there are
other methods of transportation of Eurasian mussels other than through large shipping.
Humans are also known to move around throughout their own country. This would mean
that boats can go from one river to another often containing zebra mussels, and can therefore
establish themselves in a new river via this mode of dispersal Johnson and Padilla (1996)
surveyed boaters in Lake St. Clair after Eurasian mussels had been found in 8 inland lakes in
Michigan to. Their results include: adult Eurasian mussels attaching themselves to the exterior
hull or to aquatic macrophytes entangling on the trailer or boat exterior and as larvae in live
wells, bilges, bait buckets, and cooling systems (Johnson and Padilla 1996). The boaters
surveyed provided information as to where they had been boating previously, which was in one
of the infested lakes. Of all boaters surveyed, 2.1% reported that they had used both a Great Lake
and an inland lake during the two-week survey period. By cross-examination, boaters can be
transporting Eurasian mussels to inland water bodies if they are not careful.
State parks provide people to connect with nature that may not be available in their daily
lives. The benefit of these parks is that the money received as an entrance payment goes towards
maintaining that park. As zebra mussels and quagga mussels have started to invade, they have
caused a decrease in park use for human safety reasons (Kaufmann 2012). Lakes along Lake
Champlain, including Button Bay, were closed for zebra mussel monitoring in the early 2000s
while impacts were studied (Kaufmann 2012). While biodiversity decline in lakes and rivers is
important for understanding Eurasian mussels, it is also necessary to understand their human
impacts to safety as well, leading lakes to close their doors while the spread of zebra mussels and
quagga mussels is attempted to be controlled.
32
Eurasian mussels often directly impact waterfront industries by impacting infrastructure.
The Eurasian mussels can clog water intake structures, such as pipes and screens, therefore
reducing pumping capabilities for power and water treatment plants, costing industries,
companies and communities (USGS 2016). This leads to the use of chlorine in order to control
the problems. Although chlorine itself usually does not cause environmental harm, it combines
rapidly to form chemicals such as dioxins, which are chemicals produced as a byproduct in some
manufacturing processes (like the removal of Eurasian mussels) that pollute water and
contaminate fish (Moore 2016). This is a process of bio magnification; the toxins accumulate as
they move up the food chain. Dioxins are not very soluble in water so they will cling to the
bottom of the surface and accumulate and have a half-life of more than 500 days. Carcinogens
like dioxin have been shown to increase the likelihood of infertility within aquatic organisms
seen in Lake Erie (Adedipe 2010). The introduction of carcinogens and dioxins into the water
bodies will affect the human health, especially waterfront workers that are exposed to the
chlorine for an extended period of time (Molloy 2007).
33
IDENTIFICATION OF STAKEHOLDERS
When dealing with an invasive species problem, stakeholders play an important role in
determining the total impact of the problem because once an ecosystem is invaded its disturbance
resilience decreases making it more susceptible to other foreign invaders. A Stakeholder is
someone who is directly impacted by the ecological problem, a result of previous
investment. There are numerous stakeholders with regards to the Eurasian mussel invasion in
North America. The number of stakeholders has only grown in the past two decades as a result of
their invasive nature. Among these stakeholders are the lake residents, the recreation industry,
government officials, commercial water industries, ecological scientists, and the transportation
industry (i.e. shipping).
Residents:
Residents of the lakes and waterways invaded by Zebra and quagga mussels are
important stakeholders in regards to this invasive issue. Residents are directly impacted by the
invasion due to the decreased health of the surrounding lake ecosystem and the associated human
health and economic impacts. One may argue, that residents benefit from the presences of these
Eurasian mussels because they improve the water quality. Though as stated in the problem
definition, Quagga and Zebra mussels exclude cyanobacteria when filter feeding, leaving an
expanded niche for the toxic algae to flourish, causing increased frequency of harmful algal
blooms (HABs) (Figure 10) (Maheen et al. 2013). These HABs have been known to cause
human illness (i.e. diarrhea and vomiting, sore throats, liver damage, numbness and tingling,
abdominal pain, and skin irritations). The increased concentration of cyanobacteria is what is
most troubling because it increases the probability of illness (Cyanobacteria/ Blue-Green Algae
34
Facts & Information 2016). Pets are among the most at risk because they are exposed to the
highest concentrations through consumption of water and fur absorption. In 1999 the
consumption of contaminated water from Lake Champlain resulted in the death of two dogs.
These HABs are fast encroaching, one Vermont resident, who has had a house on Lake
Champlain for 50 years states in an interview “We have never witnessed anything like what we
witnessed on Friday,” she said. “It was crystal clear Friday morning … and then within six hours
it was thick pea soup. Every hour, it just kept getting thicker and thicker and thicker.” (Stein
2012). With the increased frequency of HABs as a result of invasive Eurasian mussels residents
fear their waterfront will soon be invaded.
Another impact residential stakeholder’s face is the associated economic costs as a result
of damages due to this Eurasian mussel invasion. Many waterfront residents rely on the
surrounding waterbody for water. Since the invasion of zebra and quagga mussels residents are
forced to pay large maintenance fees to remove mussels from pipes that are exposed to the water.
Many also pay maintenance costs on motors because these Eurasian mussels will attach
themselves to any and all hard surfaces.
Anastasia Burdock, a tenth generation resident of Lake Champlain, explains that the most
common topic of conversation in reference to zebra mussels are their impact on people's feet.
Both zebra and quagga mussels have a sharp shell that can leave deep cuts when they come in
contact with the epidermis (Zebra mussels 2016). These cuts have been known to cause serious
problems to lake residents as well as other lake visitors due to risk of infection. Anastasia
35
(Burdock, personal communication)3 joked about the water shoe industry benefiting in her
interview, because swimming shoes are a must in many rocky shore fronts.
Residents are among the most important stakeholders because of their emotional
connection to the aquatic environment. To reduce risk of future invasion it is up to residents to
clean all vessels upon entering and exiting the waterbody.
Recreation industry:
The recreation industry like residents is directly impacted by the invasion of zebra and
quagga mussels for a number of the same reasons and they too hold a stake. The same health
risks apply to recreational users as due to residents, though due to increased transportation
associated with recreational use, there is an increased risk in transferring these invasives to other
lakes. It is the responsibility of the recreation industry to educate users to prevent further
transmission and setup boat cleaning stations (Great lakes: understanding the cost of invasives
2015). Scuba divers like recreational boaters play a role and transportation of zebra and quagga
mussels and it is extremely important for divers to sterilize equipment after exposure to invasive
species because they have potential to transport invaders between wrecks (Johnson 2016).
The Scuba diving industry has mixed reviews in regards to the impact of these invasive
Eurasian mussels. Due to Zebra and quagga mussels filter feeding characteristic water visibility
has increased and many divers can now see more (Johnson 2016). In Lake Erie the visibility has
increased by 77%. Though what brings many divers to the waters of the Great Lakes and Lake
Champlain are the shipwrecks. With increased water quality the shipwrecks are being spotted
3
Anastasia Burdock, Phone Interview, March 23rd 2016
36
more easily a more recently emphasized issue is their destruction to them. As stated throughout
this case study these invasive Eurasian mussels attach to all hard surfaces. Shipwrecks are now
being covered by these invasive mussels, in an interview conducted by the Washington post
Brendon Baillod the director of the Milwaukee-based Great Lakes Shipwreck Research
Foundation states “It is so bad that we can’t even see the form of some wrecks,” and then goes
on to describe the affected wrecks as “the most historic and best-preserved wrecks in the
world.”(Claiborne 2000) With increased distribution of wrecks the future dive industry may be
affected. A current debate that as resulted from this issue is whether or not the wrecks should be
removed and cleaned of these invasive mussels. Though in order for this to happen it would also
take participation of government officials’ stakeholders because all wrecks belong to a public
trust.
Government Officials:
Government officials are one of the largest stakeholders in dealing with invasive species
related problems because they are responsible for responding to social, economic, and
environmental issues associated with invasions and take in account all associated stakeholders. It
is the job of the government to develop a plan for damage control and generate a possible
solution plan to mitigate cost of damages caused by invasive species. Though the only way these
laws can be effective is if they are properly enforced.
37
Commercial Water industries:
Hydro-Electrical industries:
Due to the economic, social, and environmental impact of zebra and quagga mussels
hydro-electric industries represent a significant proportion of stakeholders in regards to this
invasive mussel issue. Since the beginning of industrialization, the utilization of waterways for
electricity has been centralized. The invasion of the Eurasian mussels has had devastating
impacts on these hydroelectric industries. Zebra and quagga mussels have caused problems by
clogging pipes (Figure 11). The effects of these invasive Eurasian mussels penetrates much
deeper than a few clogged pipes. These industrial power plants experience many ongoing effects
and endure continual maintenance costs as a result of the mussel invasion. Production is affected
by scheduled and unscheduled power outages due to cleaning and infrastructural damage. The
U.S. Fish and wildlife service predicted in 2012 if Columbia River in Oregon gets invaded the
hydro electrical industries maintenance costs could increase by $250-300 million dollars
annually (U.S.Fish & Wildlife Service 2012).
38
Figure 11. Clogged pipes due to zebra and quagga mussels.
In order to combat these invasive mussels, hydro-electric companies have been forced to
use chemical control methods to limit population growth throughout their piping systems, but
this control method comes with an environmental and social cost. The main chemical used is
Chlorine in varying forms (i.e. hypochlorite, chlorine gas, chlorine dioxide) (Meehan et al.2013).
Chlorine is effective at minimizing zebra and quagga mussels’ populations as well as non-target
species populations, including the threatened native mussels. Chlorine use poses many health
risks and in many facilities requires exposed workers to wear personal protective equipment.
With the use of any toxic chemicals extensive regulations are required costing the industry
production and money. These regulations include methods for handling and storage of toxic
wastes, as well as monitoring concentrations being discarded in the local waterways. These
health and environmental risks are often prolonged due to the physiology of the mussel. The
mussels, when threatened or stressed, closes their inhalant siphon preventing the filtering of
39
chlorine, After prolonged exposure and high concentration the chlorine eventually kills them
(Meehan et al.2013). Another characteristic of chlorine that poses an environmental and human
health effect is its ability to combine with organic compounds in the water to form carcinogenic
substances like dioxins and trihalomethanes (Molloy 2007). These carcinogenic substances have
been detected in local waterways even when current discharge regulations are met.
Water industries (municipal supplies):
Freshwater bodies are vitally important for supplying cities and residents with water for
medicinal use. Like the hydroelectric industry the associated health and environmental risks
associated with maintenance costs of infrastructure damage, is analogue. Though a risk that
poses greater threat to west coast industries, who rely greatly on reservoirs, is the cost of
constructing new infrastructure to uninvaded lakes.
A Texas article explained that the water industry was forced to increase water bill prices
by 14% to absorb the costs of a new pipeline that would bypass Lake Tacoma. Before the lake
was invaded by Zebra mussels provided 28% of the area’s total water supply (Marks
2013).Many west coast companies are now battling a similar decision, which may also impact
residents who may be unaware they are even stakeholders.
Invasive Species Scientists:
Scientist hold a very import stake when dealing with this invasive mussel problem. It has
been through their research that various control methods and potential solutions have arose
Invasive species scientists look at the ecosystem as a whole and are able to disclose the potential
environmental impacts of a solution. This scientific research has led to a detailed understanding
40
of zebra and quagga mussels’ life history and how they differ from native mussels. Through the
mapping of these Eurasian mussel’s life cycles scientists were able to determine what water
bodies are at greatest risk of invasion. This research gave an explanation for why the
Adirondacks State Park has been relatively unaffected by these invasive mussels despite
bordering invaded lakes (i.e. Lake Champlain). These Eurasian mussels during their larval stage
need high levels of calcium ions in the water to build their calcium carbonate shells (Whittier et
al 2008). The Adirondack State Parks water bodies have soft water, meaning it has low ion
concentrations, which reduces its risk for invasion because these invasive mussels are unable to
complete their life cycle. Government official stakeholders are able to use this scientific research
to develop better regulations and to know where to allocate funds, making invasive species
scientists extremely important to this invasive mussel problem.
Water- Transportation Industry:
The water transportation industry is affected by the regulations associated with the
invasion of Quagga and Zebra mussels due to the part the industry played in the initial
introduction, through the disposal of ballast water. Any ballast water regulation that are past have
a significant impact on the water transportation industry because in the United states six ships are
docked every minute (Ballast water 2016).
Ted Snieckus (Snieckus, personal communications)4 a U.S. Naval officer that specializes
in large supply ship transportation, explains in an interview that the industry has become
frustrated with these increased ballast water regulations because of the time and money that is
4
Ted Snieckus, Email Interview 15 March, 2016
41
required to obey them. The regulations have affected the workers because they are the ones
responsible for cleaning and monitoring the ballast water tanks. The regulations have become
very costly for the industry due to how expensive a water filtration system is, ranging from 1
million to 3 million dollars. The ballast water filtration system isn’t always a one-time expense,
different states and countries have different regulations and may require a different type of
system (Ballast Water 2016). Though it is the responsibility of the transportation industry
stakeholders to prevent further spread of these invasive mussels and prevent future introductions
of alien species into an already vulnerable ecosystem, like the Great Lakes and St. Lawrence
Seaway.
42
GOVERNMENTAL ISSUES
Both the federal government and the state governments of New York and Vermont
regulate the invasion of these Eurasian mussels since they share a water body as well as the
Canadian government. There are therefore a lot of considerations that need to be made while
writing regulations for the control of these Eurasian mussels in this area. For the future of the
United States’ safety from these mussels, all of these governments will need to work cohesively.
In the last two decades these Eurasian mussels have caused 8 of 14 native mussel species
in Lake Champlain to be put on the IUCN’s red list of critically endangered species (Lake
Champlain Basin Program 2016. As New York State has recognized this issue they have put into
effect stricter regulations on ballast water in large cargo ships coming in and out of the St.
Lawrence Seaway (Lake Champlain Basin Program 2016). New York State Governor, Andrew
Cuomo, has had positive things to say about increased regulation on ballast water in order to
protect the residents of New York State from further detrimental effects of invasive species like
zebra and quagga mussels. He states, “This legislation [being stricter regulations on ballast
water] ensures that the regulations governing invasive species are appropriate for New York's
farming community and plant nurseries, while also protecting the environment. I commend the
bill sponsors for their work on this legislation.” The emphasis on stricter regulation in New York
State should be mirrored throughout the country at a federal level to prevent the future spread of
these invasive mussels.
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Ballast Water Regulations
Shipping is a huge industry around the world and a global economy means that there is
no stopping it from happening. This means that the government has to develop stricter
regulations surrounding shipping, most importantly being ballast water. The St. Lawrence
Seaway sees an average of 10,000 vessels per year, varying from workboats to large cargo
freighters (Mayer et al. 2001).
Currently ships must not be within 200 nm (nautical miles) of land when exchanging
ballast water in water that is no shallower than 200m deep. Exchange at sea is required in order
to keep transported species from becoming established inland. Every ship that enters the United
States is required to have a ballast water management plan as required by the American Bureau
of shipping (Snieckus, Personal communication)5. These rules are strictly enforced in to aid in
the prevention of spreading invasive species. Interestingly, the mates on the ship have often not
even heard about invasive species and over the years have found the stricter regulations to be a
nuisance to follow (Snieckus, Personal communication)6. With the increase in stricter
regulations, there has also been an increase in ballast management exams to make sure that boats
were doing their part to prevent the spread of unknown species. Since 2006, ballast water
management requirements on the Great Lakes and St. Lawrence River have been the most
stringent in the world (Kelley, 2016). In 2007, 74% of vessels bound for the (St. Lawrence)
Seaway system from outside the Exclusive Economic Zone received a ballast management exam.
These exams consist of checking the ballast water record books that the ships are required to
5
Ted Snieckus, Email Interview 15 March, 2016
6
Ted Snieckus, Email Interview 15 March, 2016
44
make. In 2008, the percentage of vessels inspected rose to 99% and it has been at 100% since
2009 (Kelley, 2016). Since the vessels are being expected at such a thorough rate, there is less of
a chance for continued introduction of non-native species into the United States via the St.
Lawrence Seaway.
Clean Boating Act
In 2008 the Clean Boating Act (CBA) was initiated as an amendment to the Clean Water
Act. The CBA requires the Environmental Protection Agency (EPA) to identify discharges
incidental to the normal operation of recreational vessels for which management practices are
reasonable and practicable to develop. These management practices can help to limit the amount
of pollution discharged into our nation's waters. The CBA will make sure that boats (recreation
and commercial) are treating the water properly and not discharging material into the water that
does not belong there. This includes the release of antifouling and corrosion control agents,
transport of aquatic nuisance species, bilge water, cleaning and maintenance related discharges,
fishing waste and greywater (CBA 2008).
The CBA is controlled by the United States Coast Guard and is heavily monitored
however states themselves can choose to monitor the CBA with other state agencies as well, like
the Department of Environmental Conservation. There have been many mixed reactions from the
public in regards to the CBA because it doesn’t just affect commercial shipping vessels, but also
recreational boats as well. Vermont residents have stated that the CBA creates a hassle, one
forum poster of the website, FoilForum for boaters in the Vermont and New York area,
responded “I don't think anyone would disagree with cleaning up polluters, but this is clearly a
case of over legislation and would be a travesty of unintentional consequences. Requiring a
"permit" is just another way of big brother trying to control our lives and taxing us to do it.” This
45
opinion came from a user of Lake Champlain after realizing his boat needed a permit to ensure
clean waters. The fact that residents of North Country water bodies have been upset about the
cost to themselves shows that they are unclear of the problem and that they need to better
understand the ways in which Eurasian mussels have altered ecosystems.
Economics:
Speaking from a ballast water perspective, the changes that need to made in order to pass
examination and to safely exchange ballast water do not come cheap to boat owners or state
governments. The cost to switch ballast water systems can be upwards of three million dollars
(Tuxil, 2016). This high cost is almost unbearable when the regulations are possibly different
from state to state. With some states requiring stricter regulations, like New York State, ships
will have to comply with the strictest regulations. Therefore, even though the regulations on the
West Coast are not as strict and are cheaper to bypass, the vessels will have to succumb to
having the management plans and technology to comply with the New York State regulations.
In New York State, controlling invasive species can cost between $200 to $2,000 per
lake-acre each year (Tuxil, 2016). Without the help of the federal government on actual effective
measures for population control and eradication, the state governments have to find funding for
this elsewhere. Lake Champlain is 410 lake acres, therefore the total cost to the state in order to
control invasive mussels would cost between $82,000 and $820,000 dollars per year. This is the
cost of only one water body. The large dichotomy between minimum and maximum pricing
suggests that it is also hard to predict the actual cost of controlling these Eurasian mussels.
46
Recreation Restriction
With the introduction of zebra mussels and quagga mussels into the North Country water
bodies, people have had to become more aware of the water that they are using. Often times, the
state government will have to shut down a section of the beach due to harmful algal blooms and
cyanobacteria that could make recreational users sick. This makes people with lake front
property angry due to their lack of access to the lake when they paid so much money for their
homes. Restrictions for use by the government may also come from another safety risk; the
mussels are very sharp and can puncture people’s feet. For state parks to ensure the safety of
their visitors, they sometimes have to shut down the lake from recreation use so people do not
harm their bodies from the mussel shells. Shutting down the park will lead to a loss in economic
gain for that season. At a resort on Lake Erie in 2010, residents were warned not to swim in or
even boat in the water. Tourism to the region fell about 50% in the next two years (Mayer et al.
2001). When the algal blooms created by Eurasian mussels and agricultural runoff negatively
affect water bodies, there will be less use of the lake and tourism industries will begin to see a
decline in numbers. The counties of New York State and Vermont that compose of the North
Country are some of the poorest in their respective states and tourism is a large portion of where
their economy comes from. As the biodiversity continues to decline in these lakes and rivers,
tourism will no longer be feasible.
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DEVELOPMENT OF SOLUTIONS TO THE PROBLEM
Parameterizing solutions
A solution for the invasion of zebra and quagga mussels requires a multi-dimensional
solution because the population status throughout different invaded water bodies varies. A
satisfactory solution would control or eradicate the invasive mussel population, minimize loss of
biodiversity, be easy to implement, have a low overall cost, and accommodate majority of
stakeholders. With any invasive species solution the limiting factor is usually cost and it is
important to take into account long-term costs both economically, socially, and environmentally
when deciding on implementing a solution.
North Country Failures
The North Country has been dealing with Eurasian mussels for nearly two decades. At
this point, the only hope for solutions is to control the species rather than eradicate the species.
There have been a few attempts at eradication over the years that have failed, therefore before
going into our solutions for prevention and control the context of North Country failures is
important to reflect upon. Many other early methods of control and eradication revolved around
physical removal and the use of chemicals in order to either delay or stop reproduction, or to aid
in the removal of the species.
Physical control of Eurasian mussels was the most effective solution that the North
Country and the great lakes had for a while (Maxwell 1992). Physical scraping of mussels from
water systems is a viable method for control, until the mussels have overpopulated. Scraping is
most effective in large areas where mussels are found in high concentrations, where access for
personnel and equipment is available, and where the area can be taken out of service for long
48
enough periods of time that divers can remove the accumulated mussels. This method, however,
is very expensive in terms of labor and lost production (Maxwell 1992). In order to keep up with
the Eurasian mussels after their population boom, it would become less efficient.
Another large aspect of controlling the species with hope of eradication within the North
Country would be reproductive control. Introducing serotonin into the mussels’ environment was
used to override the natural spawning cues and disrupt the natural reproductive process of the
mussels (Michigan Sea Grant College Program 1994). If zebra mussels are artificially activated
to spawn when phytoplankton levels are low, there would be little food available for larvae and
the offspring would die before settling. If a chemical applied to mussels in a specific area causes
them to spawn, this might trigger a chain reaction between males and females based on
pheromones that would spread some distance beyond the initial application site (Michigan Sea
Grant College Program 1994). However, similarly to many solutions being used today, this form
of reproductive control was too costly.
The North Country began trying to control and eradicate the species after it had become
too late. All methods of eradication are near impossible now and people have come to accept the
changed ecology of the lakes and rivers, to an extent. However, that does not mean giving up on
control is an option, whether that be here in the North Country or out on the West Coast in
California. Control mechanisms and even potential eradication mechanisms are possible for
finally silencing these Eurasian mussels.
49
Identification and evaluation of potential solutions
Zequanox (Closed System Solution):
The New York State Commercial Water Industry stakeholders were tired of the
maintenance costs of chlorine and were asking local universities to develop an alternative
solution for Eurasian mussel removal. Dr. Molloy of the University of Albany developed
Zequanox, a product that is 99.9% effective at killing zebra and quagga mussels, while excluding
native mussels and other non-target organisms. The product was developed to reduce the use of
chlorine and other chemical pollutants from invading the surrounding waterways and minimizing
human exposure risks. Zequanox is an organic pesticide that uses a naturally occurring dead
powdered bacterium (Pseudomonas fluorescens) to degrade the digestive tract of zebra and
quagga mussels resulting in fatality (Molloy 2007; Gonyou 2014). This product was developed
to be used in a closed-system, like hydroelectric plant piping and ballast water chambers. When
used in a closed-system the likelihood of shifting the mussel population to becoming resistant is
low due to the product's effectiveness. Dr. Molloy explained in our interview that when used in a
closed-system the likelihood of that .1% entering back into the hydroelectric plant is of low
probability
Advantages of Zequanox over alternative methods are that it can; reduce invasive mussel
populations at all life stages, it can be effective in a range of water temperatures, treatments do
not disrupt operations, no equipment is needed to install or maintain, minimal protective
equipment is needed, and detoxification of water is not needed before discharge. The
Environmental Protection Agency (EPA) in 2011 declared Zequanox to be a low risk
pesticide and in part as minimal regulations when used in a closed-system. Zequanox is of low
risk to the aquatic environment and there is no record of mortality in any non-target species,
50
including other bivalves and fish (Kulwiec 2015). Though the label states that it has potential to
be toxic to non-target species and should not be applied during critical breeding seasons
(Kulwiec 2015). Zequanox decreases threats to biodiversity, as well as, reduces social and
economic costs associated with chemical alternatives. Dr. Molloy explained on the phone that
the reason why the commercial water industry has not switched over to using Zequanox is that
when compared to chlorine in monetary terms it cost more, but if one were to add in the
maintenance fees chlorine would cost a lot more.
Open-system solution:
Zequanox was originally intended for use on a closed water system recently with
Eurasian mussels’ rapid westward expansion, the use of Zequanox on an open system is being
discussed. On Christmas Lake in Minnesota, Zequanox was applied as a rapid response
mechanism just weeks after the Minnesota had approved it for open water use (Gonyou
2014). The Lake detected four zebra mussel juveniles on August 16th 2014 and presented a
perfect opportunity to test the open water use of Zequanox for eradication. The infested area was
sectioned off making a 50ft by 50ft area that was on average 2.5ft deep (Zequanox(R) Achieves
100% Mortality for Invasive Mussels in Minnesota Lake 2014). Before application the zebra
mussel population had reached 5,000 inside the isolated area. The Zequanox treatment was
administered on September 8th and 100% mortality was recorded eleven days later within the
treatment area (Zequanox(R) Achieves 100% Mortality for Invasive Mussels in Minnesota Lake
2014). The total cost of the Zequanox treatment in Christmas Lake was $9,300 and there were no
recorded effects on native mussels.
51
Potassium Chloride:
Potassium Chloride, also known as Potash, has been the only successful method of
eradication (100% removal) of Zebra mussels in the United States (Zebra Mussel Eradication at
Millbrook Quarry 2016). This method has not been approved by the U.S. Environmental
Protection Agency (EPA) and requires a permit for use. Permits have been approved by the EPA
in three states currently, Virginia, Texas, and Minnesota (Zequanox(R) Achieves 100% Mortality
for Invasive Mussels in Minnesota Lake 2014). The use of potash is best in areas of high
concentrations of the invasive mollusks and where there is little water flow because it is
important for the targeted group to have continuous exposure for the treatment to be successful
(Zebra Mussel Eradication at Millbrook Quarry 2016). Potash targets all species in the family
Mollusca, threatening already endangered mussels. Potash also persists in the environment for an
extended period of time, affecting non-target species, as well as restricting recreation and public
water consumption (Zequanox(R) Achieves 100% Mortality for Invasive Mussels in Minnesota
Lake 2014).
Zebra mussel traps:
Zebra mussel traps were designed to reduce larval numbers in an infested lake. The trap
designed by Shoreline Industries is 8 inches wide and 20 inches tall, has five layers of collection
surface, and a handle on top to suspend it (Kaufmann 2012). The trap is marketed currently at
$69.99. This product's purpose is to attract female Zebra mussels to the hard surface to then be
removed. A single female Zebra mussel can produce 1 million offspring and by removing
females the population can be decreased. The product is suggested to be used in 6 to 8 feet of
water and to be placed every 25ft around the lake front. The traps are suggested to be cleaned
52
and replaced every 2 months. The product is described to work like flypaper, baiting the juvenile
mussels by having an attractive hard surface to attach too (Kaufmann 2012).
Introduce the predator the Black Carp:
Black Carp (Mylopharyngodon piceus) have been proposed to be used as a biocontrol to
combat Zebra mussels. Black Carp were accidentally introduced to Europe and were recorded to
eat Zebra mussels there (Savini 2010). Though the Black Carp have similar range of Zebra and
quagga mussels in Asia, it is unlikely they would be effective at reducing Zebra and quagga
mussel populations do to their small mouths not being able to break up the invasive mussels shell,
and native mussels would be more appetizing (NAS 2016). The Black Carp is a non-native
species that has potential to cause devastating effects much like the current Eurasian mussel issue
on native mussel populations. With recent introduction into the Mississippi river watershed there
is great fear to the native mussel populations, where three-fourths are considered threatened or
endangered (Stafford 2016). Zebra mussels are what has led to the threatened and endangered
status of native mussels and have potential to team up with the Black carp to collapse the
remaining native mussel populations.
Boat Cleaning:
Boat cleaning is of vital importance to reduce the transport and spread of Zebra and
quagga mussels. Having boat cleaning stations set up upon entering and leaving the lake can not
only reduce the transport between waterways, but also limit the number of new introductions to
the already fragile ecosystem. When cleaning a boat between waterbodies it is important to be
thorough making sure not to miss a step (Harmful Aquatic Hitchhikers: Mollusks: Zebra Mussel
2016).
53
Boat cleaning steps:
1. Examine all equipment exposed invaded water. Look for visible vegetation.
2. Flush bilge, or any water storage area with tap water (use hot water if available).
3. Leave boat to drive for a minimum of 48 hours.
4. Examine equipment for mussels.
5. If removal is too difficult leave boat out of water for a minimum of five days
before reentry.
Ballast Water Regulations:
Ballast water has not only been the mode of transportation for the Quagga and Zebra
mussel, but is also said to be responsible for 30 other invasive species introduction in the great
lake systems (i.e. Eurasian watermilfoil, Sea lamprey, Chinese mitten crab) (Sussman 1978;VPR
Interview with Mary Watson 2012). The University of Vermont in 2012 announced the
invention of a ballast water treatment machine that can be mounted in the engine room of cargo
ships (A Sound Way to Stop Stowaways 2012). This machine differs from other treatment
systems because instead of using harsh chemicals, or UV that doesn’t always penetrate through
murky waters, the machine relies on ultrasound transducers. The ultrasound transducers are
effective at treating the water through the creation of bubbles that form a wave like structure that
rip apart the organisms hitchhiking in the ballast water. What makes this treatment system
superior to others is the absence of secondary pollution. This system is effective and efficient at
reducing stowaways and is safe and easy to operate (Hielscher 2016). The system like other
ballast water treatment systems is expensive costing upwards to 1 million dollars, though longterm it could cost less than other systems because it doesn’t need continual purchasing of
chemicals.
54
Education:
Increased education about zebra and quagga mussels, as well as, other invasive species is
extremely important to reduce introductions and spread to other waterbodies in North America.
We will go into further detail relating to the North Country and western United States later in
this section, but it is important to note a few big picture ideas. It has been noted that increased
awareness on invasive species greatly decreases the likelihood that they will spread to places that
they have not been seen in. Therefore, through introducing residents to the problem through
flyers at state parks or even into curriculum of primary school students, there will be an
increased awareness and decreases spread of zebra and quagga mussels.
Identification of feasible solutions:
Feasible:
Potassium Chloride “Potash”:
Determining whether the use of Potassium Chloride is a feasible solution for eradication
is challenging. Potassium Chloride has been the only substance to have 100% results for
eliminating Zebra mussels, but it also eliminates native mussels who are currently threatened
(Zebra Mussel Eradication at Millbrook Quarry 2016). Ways to reduce effects on native mussels
is to remove as many native mussels prior to treatment (Dr. Molloy, personal communication)7.
Currently the EPA has not approved the use of Potassium Chloride due to its potential human
health risks. The use is allowed through permit application and lake assessment (Zequanox(R)
Achieves 100% Mortality for Invasive Mussels in Minnesota Lake 2014).
7
Daniel P. Molloy, phone interview, March 16th 2016
55
Zequanox:
The use of Zequanox in a closed system is very feasible. Aside from the significant
overhead cost, the use of Zequanox in hydroelectric plants and in large vessels would not only
help control zebra and quagga mussel populations, but would also reduce the environmental and
social impacts the alternatives have (i.e. chlorine).
The use of Zequanox in an open system is still being researched to determine the effect
on the overall ecosystem. As stated above a fear with any pesticide is the risk of shifting to a
resistant population. Though in regards to zebra and quagga, mussels if the population were to
become resistant the environmental effects would be no worse than if nothing were done at all.
Zebra mussel traps:
Zebra mussel traps are a feasible solution because they have little economic, social, and
environmental cost. Though their effectiveness is significantly lower than other solutions, and
they are a tool to merely control population size.
Boat Cleaning:
Boat cleaning is a feasible solution due to its effectiveness at reducing transportation and
introduction of invasives species. Boat cleaning is a relatively low cost solution and though it
does not change the population status of a lake it reduces the destruction of other aquatic
ecosystems.
Education:
Education is the most inexpensive way at reducing transportation and introduction of
invasive species and is extremely feasible. Citizen science is a great way to educate the public
56
and get them involved with the invasive issues. New York State has a program the Drop-a-Brick
Program through the Lake George Association (LGA). The nature of this proactive program is to
act as an early detection network for zebra mussels. In the Drop-a-Brick program, each volunteer
participant suspends a brick from their dock. Favoring hard surfaces, zebra mussels attach
themselves to the brick. At the end of the summer season, the participants check the brick and
report whether they have found evidence of zebra mussels. In the program's first year, more than
80 people participated, covering every municipality in the Lake George Basin. With the help of
the Coast Guard Auxiliary, the Lake George Association was also able to monitor many of the
islands that dot Lake George. This model has applicability to other regions of the State,
particularly for detecting invaders that are transient or not easily monitored (Sanford et al. 2005).
These types of programs will allow the public to better understand what the problem is, allowing
them to be active about pursuing conservation and bettering the environment. Without education
and early detection, it becomes increasingly more difficult to eradicate a species.
Ballast Water Treatment:
To have every cargo ship in the United States install a water treatment system would be
extremely expensive. Though the overall cost of the environment and maintenance cost once
Zebra and quagga mussels have been established is far greater than the overhead fee, making this
a feasible solution.
Identification of Best Solutions
Now that we have determined which solutions are feasible it is important to figure out
what the best solutions are. In regards to Zebra and quagga mussels there are a variety of
57
solutions that address different aspects of the problem; Industrial maintenance, transportation,
and population control/eradication. The best solution for reducing environmental, social, and
economic cost in the commercial water industry would be to increase the use of Zequanox.
Zequanox is far more effective and less invasive to humans and the environment than the
alternatives solutions. In areas of recent introduction Zequanox also has potential to be the best
rapid response agent to eradicate the invasive mussels, while minimizing biodiversity loss of
non-target species.
To reduce transportation and other introductions of invasive species there are two levels
of action that should be addressed; large scale shipping, and small scale lake users. The best
solution for reducing transportation and introduction of invasive species, is the installation of
ballast water treatment systems. The best solution for reducing the transportation of invasive
species by small scale lake users is increased public education and boat cleaning practices. For
both aspects of transportation these solutions have the greatest effect on reducing further
invasion.
The best solution for local control and residential impact is through the use of Zebra
mussel traps. These traps are easy to use and can help to reduce population growth in the water
front area if used as directed. To achieve full eradication and minimize biodiversity loss there is
still research to be done, but these methods suggested have potential to reduce costs and
biodiversity impacts associated with Zebra and quagga mussels as well as other invasive species.
58
EASE OF IMPLEMENTATION
In order for any of the feasible solutions we proposed to be acceptable there also needs to
be implementation of other solutions simultaneously. In order for this to occur, all of the
stakeholders involved in Eurasian mussels will need to agree on a plan of action. Once the
weaknesses of each solution are solved, together the three solutions will help to prevent future
biodiversity loss caused by Eurasian mussels. As well as economic and social costs in areas that
are already affected by Eurasian mussels.
Zequanox
Stakeholders in waterfront industry will not be easy to convince of the use of Zequanox
as a substitute for chlorine. Zequanox, though has been proven to be 99.9% effective in
eradication, can be costly to industry owners. Providing incentives for waterfront industries to
use Zequanox would not only be beneficial for the stakeholders but also beneficial for the
environment. If the US government were to provide aid for the industry owners, perhaps there
would be wider acceptance of the use of Zequanox instead of chlorine. As it stands right now, in
order for Zequanox to be widely accepted for industrial use instead of chlorine, the government
would have to aid in making Zequanox affordable. Zequanox will get pushback from both
industry and government workers until there is a price that is feasible and understandable for
both to be paying.
Boat Cleaning
Residential users of the lake will have to agree to put in the time and effort in order to
make this a successful solution. Often residential users want to leave the lake rather quickly and
59
taking the time to clean their boats and release lake water from their tanks is timely (Burdock,
personal communication)8. If residential users were able to have an incentive of cleaning their
boats, it may make the implementation of this solution easier. Boat cleaning stations at docks
would be an easy way in which to put this plan into action.
Education
Education needs to be focused on invasive species prevention. By proving NGOs and
governmental organizations the important facts on Eurasian mussels, they will be better equipped
to distribute information to the masses when need be. By distributing information on Eurasian
mussels to boaters and recreational users at state parks as they enter, the word will be widely
spread to visitors about the invasive issue.
8
Anastasia Burdock, Phone Interview, March 23rd 2016
60
IMPLEMENTATION PLAN
The best solutions for the invasion of Eurasian mussels will be three-fold. Step 1 will be
educating the public better on the problem, step two will be initiating better boat cleaning
behaviors and step three will be increasing the use of Zequanox as both preventative measure
and a tool for control and potential eradication. The best solution to start with is education.
Educating the public on the topic decreases the transfer of the Eurasian mussels between
water bodies. This could be done using flyers to be distributed at recreation parks across the
state(s) so that visitors gain an understanding of the problem that is occurring and the change in
biodiversity that happens because of foreign mussels. Flyers could include basic biology of
Eurasian mussels and show some of the historical impacts of which they have had on water
bodies. The environmental effects of these mussels, how the spread can be decreased, and why
the public should care can be easily addressed through a variety of outlets. Through the use of
public television and radio, as well as the word of mouth, these issues can be addressed. This is
extremely important as these mussels begin to move out west (as their current trajectory
predicts). Bringing invasive species awareness into schools is also an important arena for
educating the public on invasive issues. By having a selection of the curriculum in public schools
devoted to invasive species awareness of an area, kids will be able to feel encouraged to act on
the problem and hopefully spread the word to their parents. Encouraging the youngest learners is
a great way to extend knowledge on the issue. This will therefore increase public awareness by
integrating the community into the problem.
Boat cleaning with therefore be a byproduct of increasing education on the problem. As
people become more aware they will recognize the importance of preventing the future spread of
61
these Eurasian mussels. It would be useful to also include boat cleaning stations for recreational
users near boat launches so that users can easily clean their boats upon exiting the water body.
Increasing Zequanox use, in larger and more water bodies, would require the US
government to begin providing industries with subsidies in order to afford Zequanox. By
providing government subsidies, Zequanox will become more affordable and industries will no
longer have to depend on chlorine or other chemical solutions with harmful side effects, both to
the environment and the human health. The payment of these subsidies will come from public
tax dollars. Though we are not proposing to increase taxes, we are proposing a way to manage
tax dollars so that the money goes towards the things that matter environmentally, and in the
North Country and the west of the continental United States, that includes population control of
Eurasian mussels.
We propose this implementation plan in this cascading effect because it will gain the
most awareness. Once people are better informed on the environmental impacts of the species
they will not be as upset hearing that some of their tax dollars are going towards subsidies for
Zequanox. The government provides farmers with subsidies for other resources like corn, it’s
time the government also thinks about even the smallest organisms and help save the aquatic
ecosystems they live in.
62
CONCLUSIONS
What we have learned from this case study is that in order to solve this invasive species
problem a variety of stakeholder interests need to be considered when creating solutions. We
have emphasized throughout this case study how the North Country is where the problem really
began, however as the problem persists now it has turned to an area of management and not an
area of eradication. North Country water bodies (Lake Champlain, Lake Ontario, Lake Erie and
the St. Lawrence River) have been infested with Eurasian mussels for an extended period of time
and so from this invasion it is important to learn from mistakes.
Education is that the forefront of importance in terms of reducing the impact of Eurasian
mussels in surrounding waterways and preventing their future spread out west. We have watched
as Eurasian mussels have outcompeted 8 of 14 native mussels in Lake Champlain, decreased
phytoplankton levels by massive amounts (sometimes upwards of 80%) in North Country water
bodies and have witnessed how the change in these phytoplankton levels leads to a bottom up
trophic cascade reducing numbers of yellow perch and other planktivorous fish native to North
Country water bodies. These biodiversity impacts reiterate the importance of focusing on
education. Education will provide information on how Eurasian mussels are transported as well
as informing the public on the greater biodiversity costs (like those listed above), economic
costs, and health risks associated with these invasive Eurasian mussels. By having a bettereducated public, better policy can be established for invasive species that can be agreed upon by
all stakeholders.
Often times, people want to take the easy way out when dealing with an issue like
invasive species. However, in the case of Eurasian mussels the easy way out (i.e. using chlorine
and other chemical substances for removal) will have a greater impact on the environment when
63
we look long term. Maintenance costs for these types of solutions are also high, so though it may
seem like the cheap and easy solution, it will actually cost more in the long run (Meehan et al.
2013). Switching to a substance like Zequanox will have greater overhead cost, but will result in
fewer maintenance fees over time. Zequanox will result in reduced social costs as well because
stakeholders will have reduced exposure to the toxic components of chlorine.
Zebra and quagga mussels are on the move out west. West coast researchers are trying to
solve the problem by contacting East Coast researchers who have previously dealt with the
problem. Though it may be too late for eradication in the North Country, the knowledge
generated from decades of research has the potential to be used effectively out west. Let’s not
repeat history. We need to use resources like Zequanox to act in rapid response to these
invasions before it is too late. By educating the public sooner rather than later the control costs of
eradication will be significantly less, as the population of mussels will still be manageable and
eradication will be feasible.
64
ACKNOWLEDGEMENTS
We would like to thank Dr. Erika Barthelmess for her support and guidance throughout
writing this paper, helping to mold our project into something feasible and answering our
numerous questions throughout the entire process. Dr. Brad Baldwin for taking the time to
conduct and interview with us as well as for strengthening our study by sharing with us different
directions we could go in. Dr. Molloy, Ted Snieckus, Larry Eichler and Anastasia Burdock for
taking the time to talk with us on the phone for allowing us to gather the opinions of real
stakeholders in this issue.
We would lastly like to thank the entirety of our Conservation Biology peers who have
all worked tirelessly throughout this semester and have helped us stayed positive when times got
rough!
65
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TABLE AND FIGURE CITATIONS
Figure 2. http://www.invadingspecies.com/wp-content/gallery/zebra-and-quagga-mussels/u-senvironmental-protection-agency-great-lakes-national-program-office.jpg
Figure 3. http://www.ncrcd.org/files/5213/6002/0914/zebra_and_quagga_mussels_10.jpg
Figure 4.
Whittier TR, Ringold PL, Herlihy AT, Pierson SM. 2008. A calcium-based invasion risk
assessment for zebra and quagga mussels (dreissena spp). Frontiers in Ecology and the
Environment 6(4):180-4.
Figure 5. https://lakechamplainea.files.wordpress.com/2010/04/foodweb1.jpg
Figure 6. USGS
Science for a changing world [Internet]. 2015. Current Quagga mussel sightings
distribution.[Cited 2016 03/27] Available from:
http://nas.er.usgs.gov/taxgroup/mollusks/zebramussel/
Figure 8. http://ucanr.edu/sites/WAEMAP/files/137109.jpg
Figure 9. http://ijc.org/php/publications/html/modsum/depintof5.jpg
Figure 10. Algae blooms hit Champlain in wake of record phosphorus runoff [Internet]: Addison
Independent; c2012 [cited 2016 May 11]. Available from:
http://www.addisonindependent.com/201207cyanobacteria-blooms-hit-champlain-wakerecord-phosphorus-runoff .
Figure 11. http://www.co.cottonwood.mn.us/files/7214/3387/0298/Zebra_mussels_pipe.jpg
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APPENDICES
Appendix A: Interview Questions
1.
2.
3.
4.
What past and current methods of eradication or control are being used that you know of?
How have you seen the biodiversity of the waterways change?
Is there any promise of eradication?
How we have adapted to deal with the problem and is that a good thing? Should we just
be dealing with it and not be trying to come up with a solution at this point?
5. Do you know how this problem has affected other industries (fishing)?
6. How much is being spent on eradication/control each year?
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