The
zebra mussel,
Dreissena polymorpha, is a small
freshwaterFresh water is naturally occurring water on the Earth's surface in ice sheets, ice caps, glaciers, bogs, ponds, lakes, rivers and streams, and underground as groundwater in aquifers and underground streams. Fresh water is generally characterized by having low concentrations of dissolved salts and...
musselThe common name mussel is used for members of several families of clams or bivalvia mollusca, from saltwater and freshwater habitats. These groups have in common a shell whose outline is elongated and asymmetrical compared with other edible clams, which are often more or less rounded or oval.The...
. This species was originally native to the lakes of southeast
RussiaRussia or , officially known as both Russia and the Russian Federation , is a country in northern Eurasia. It is a federal semi-presidential republic, comprising 83 federal subjects...
being first described in 1769 by a German zoologist
Peter Simon PallasPeter Simon Pallas was a German zoologist and botanist who worked in Russia.- Life and work :Pallas was born in Berlin, the son of Professor of Surgery Simon Pallas. He studied with private tutors and took an interest in natural history, later attending the University of Halle and the University...
in the
UralThe Ural or Jayıq/Zhayyq , known as Yaik before 1775, is a river flowing through Russia and Kazakhstan. It arises in the southern Ural Mountains and ends at the Caspian Sea. Its total length is 1,511 mi making it the third longest river in Europe after the Volga and the Danube...
, Volga and Dnieper rivers. They are still found nearby, as Pontic (
Black SeaThe Black Sea is bounded by Europe, Anatolia and the Caucasus and is ultimately connected to the Atlantic Ocean via the Mediterranean and the Aegean seas and various straits. The Bosphorus strait connects it to the Sea of Marmara, and the strait of the Dardanelles connects that sea to the Aegean...
) and
CaspianThe Caspian Sea is the largest enclosed body of water on Earth by area, variously classed as the world's largest lake or a full-fledged sea. The sea has a surface area of and a volume of...
(Caspian Sea) species. However, it has been accidentally
introducedAn introduced species — or neozoon, alien, exotic, non-indigenous, or non-native species, or simply an introduction, is a species living outside its indigenous or native distributional range, and has arrived in an ecosystem or plant community by human activity, either deliberate or accidental...
in many other areas, and has become an
invasive species"Invasive species", or invasive exotics, is a nomenclature term and categorization phrase used for flora and fauna, and for specific restoration-preservation processes in native habitats, with several definitions....
in many different countries worldwide.
Zebra mussels superficially resemble marine mussels in the family
MytilidaeMytilidae is a family of small to large saltwater mussels, marine bivalve mollusks in the order Mytiloida. It is the only family in the order...
, and like them, are attached to solid substrates with a
byssusByssus means both a silky filament by which certain molluscs attach themselves to hard surfaces, and a rare fabric, also called sea silk and its fibre source.-Word:...
. However, zebra mussels are not at all closely related to the mytilids; they are much more closely related to the
VeneridaeThe Veneridae or venerids, also known as the Venus clams, are a very large family of minute to large, saltwater clams, marine bivalve molluscs. There are over 500 living species of venerid bivalves, most of which are edible, and many of which are exploited as a food source.Many of the most...
, the
Venus Venus is a Roman goddess principally associated with love, beauty, sex,sexual seduction and fertility, who played a key role in many Roman religious festivals and myths...
clams.
Zebra mussels get their name from a striped pattern which is commonly seen on their shells, though not all shells bear this pattern. They are usually about the size of a fingernail, but can grow to a maximum length of nearly 2 in (5.1 cm). The shape of the shell is also somewhat variable.
Anatomy
Zebra mussels are relatively small, with adults ranging from 0.25 to 1.5 in (0.635 to 3.8 cm) long. They have tiny stripes down their shells. Zebra Mussels have a D-shaped shell. They attach to things with 'strings',
byssalByssus means both a silky filament by which certain molluscs attach themselves to hard surfaces, and a rare fabric, also called sea silk and its fibre source.-Word:...
threads, which come out of their
umboUmbo may refer to:*A shield boss* umbo , at the top of some mushrooms*The Umbo of tympanic membrane - a part of the human body*Umbo is the part of a Bivalve shell which was formed when the animal was a juvenile...
on the dorsal (hinged) side. Removal of the mussel is therefore difficult.
Ecology
Zebra mussels and the closely related and ecologically similar
quagga musselThe quagga mussel is a subspecies of freshwater mussel, an aquatic bivalve mollusk.It is one of seven Dreissena species and has an average life span of 3 to 5 years....
s are
filter-feedingFilter feeders are animals that feed by straining suspended matter and food particles from water, typically by passing the water over a specialized filtering structure. Some animals that use this method of feeding are clams, krill, sponges, baleen whales, and many fish and some sharks. Some birds,...
organisms. They remove particles from the water column. Some particles are consumed as
foodFood is any substance consumed to provide nutritional support for the body. It is usually of plant or animal origin, and contains essential nutrients, such as carbohydrates, fats, proteins, vitamins, or minerals...
, and
fecesFeces, faeces, or fæces is a waste product from an animal's digestive tract expelled through the anus or cloaca during defecation.-Etymology:...
are deposited on the lake floor. Non-food particles are combined with
mucusIn vertebrates, mucus is a slippery secretion produced by, and covering, mucous membranes. Mucous fluid is typically produced from mucous cells found in mucous glands. Mucous cells secrete products that are rich in glycoproteins and water. Mucous fluid may also originate from mixed glands, which...
and other matter and deposited on lake floors as
pseudofecesPseudofeces or pseudofaeces are a way that filter-feeding bivalve mollusks get rid of suspended particles which have been rejected as unsuitable for food. The rejected particles are wrapped in mucus, and are expelled without having passed through the digestive tract...
.
Lake floor food supplies are enriched by zebra mussels as they filter pollution out of the water. This biomass becomes available to bottom feeding species and to the fish that feed on them. The catch of
yellow perchThe yellow perch is a species of perch found in the United States and Canada, where it is often referred to by the shortform perch. Yellow perch look similar to the European perch, but are paler and more yellowish, with less red in the fins. They have six to eight dark, vertical bars on their sides...
increased 5 fold after the introduction of zebra mussels into
Lake St. ClairLake St. Clair is a fresh-water lake named after Clare of Assisi that lies between the Province of Ontario and the State of Michigan, and its midline also forms the boundary between Canada and the United States of America. Lake St. Clair includes the Anchor Bay along the Metro Detroit coastline...
.
Zebra mussels attach to most
substratesStream substrate is the material that rests at the bottom of a stream. There are several classification guides. One is:*Mud – silt and clay.*Sand – Particles between 0.06 and 2 mm in diameter.*Granule – Between 2 and 4 mm in diameter....
including sand,
siltSilt is granular material of a size somewhere between sand and clay whose mineral origin is quartz and feldspar. Silt may occur as a soil or as suspended sediment in a surface water body...
, and harder substrates. Other mussel species frequently represent the most stable objects in silty substrates, and zebra mussels attach to, and often kill these mussels. This has eliminated many native mussel species from affected lakes in North America. This pattern is being repeated in Ireland where zebra mussels have eliminated the two freshwater mussels from several waterways, including some lakes along the
River ShannonThe River Shannon is the longest river in Ireland at . It divides the west of Ireland from the east and south . County Clare, being west of the Shannon but part of the province of Munster, is the major exception...
.
Life cycle
The life span of a zebra mussel is four to five years. A female zebra mussel begins to reproduce within 6-7 weeks of settling. (see Borcherding, J. (1991): The annual reproductive cycle of the freshwater mussel Dreissena polymorpha Pallas in lakes. Oecologia 87: 208-218) Oecologia 87:208-218.
In terms of reproduction, zebra mussels are among the most prolific of all animals. An adult female zebra mussel may produce between 30,000 and one million eggs per year.
SpawningSpawn refers to the eggs and sperm released or deposited, usually into water, by aquatic animals. As a verb, spawn refers to the process of releasing the eggs and sperm, also called spawning...
usually begins in the months from late spring to early summer by free-swimming larvae (
veligerA veliger is the planktonic larva of many kinds of marine and freshwater gastropod molluscs, as well as most bivalve mollusks.- Description :...
s), which are microscopic in size, thus invisible to the naked human eye. About two to five percent of zebra mussels reach adulthood.
Predators
There are a number of natural predators of zebra mussel. Zebra mussels have high nutritional value (Walz, 1979 ) and are consumed in large quantities by
crayfishCrayfish, crawfish, or crawdads – members of the superfamilies Astacoidea and Parastacoidea – are freshwater crustaceans resembling small lobsters, to which they are related...
,
waterfowlWaterfowl are certain wildfowl of the order Anseriformes, especially members of the family Anatidae, which includes ducks, geese, and swans....
and in smaller quantities by
muskratThe muskrat , the only species in genus Ondatra, is a medium-sized semi-aquatic rodent native to North America, and introduced in parts of Europe, Asia, and South America. The muskrat is found in wetlands and is a very successful animal over a wide range of climates and habitats...
s.
Crayfish could have a significant impact on the densities of 1 to 5 mm long zebra mussels. An adult crayfish consumes an average of nearly 105 zebra mussels every day, or about 6000 mussels in a season. Predation rates are significantly reduced at cooler water temperatures.
Several species of fish consume zebra mussels. Of these,
roachRutilus is a genus of fishes in the family Cyprinidae, commonly called roaches. Locally, the name "roach" without any further qualifiers is also used for particular species, particularly the Common Roach Rutilus (Latin for "shining, red, golden, auburn") is a genus of fishes in the family...
seems to have the most significant impact on mussel densities. In some Polish lakes the diet of the roach consists almost exclusively (~95%) of zebra mussels (Stanczykowska, 1957). Despite all this, it seems that fish do not limit the densities of zebra mussels in European lakes.
Smallmouth bassThe smallmouth bass is a species of freshwater fish in the sunfish family of the order Perciformes. It is the type species of its genus...
are a predator in the zebra mussels' adopted North American
Great LakesThe Great Lakes are a collection of freshwater lakes located in northeastern North America, on the Canada – United States border. Consisting of Lakes Superior, Michigan, Huron, Erie, and Ontario, they form the largest group of freshwater lakes on Earth by total surface, coming in second by volume...
habitat* Habitat , a place where a species lives and grows*Human habitat, a place where humans live, work or play** Space habitat, a space station intended as a permanent settlement...
.
As an invasive species
The native distribution of the species is in the
Black SeaThe Black Sea is bounded by Europe, Anatolia and the Caucasus and is ultimately connected to the Atlantic Ocean via the Mediterranean and the Aegean seas and various straits. The Bosphorus strait connects it to the Sea of Marmara, and the strait of the Dardanelles connects that sea to the Aegean...
and
Caspian SeaThe Caspian Sea is the largest enclosed body of water on Earth by area, variously classed as the world's largest lake or a full-fledged sea. The sea has a surface area of and a volume of...
in
EurasiaEurasia is a continent or supercontinent comprising the traditional continents of Europe and Asia ; covering about 52,990,000 km2 or about 10.6% of the Earth's surface located primarily in the eastern and northern hemispheres...
. Zebra mussels have become an
invasive species"Invasive species", or invasive exotics, is a nomenclature term and categorization phrase used for flora and fauna, and for specific restoration-preservation processes in native habitats, with several definitions....
in
North AmericaNorth America is a continent wholly within the Northern Hemisphere and almost wholly within the Western Hemisphere. It is also considered a northern subcontinent of the Americas...
,
Great BritainGreat Britain or Britain is an island situated to the northwest of Continental Europe. It is the ninth largest island in the world, and the largest European island, as well as the largest of the British Isles...
,
IrelandIreland is an island to the northwest of continental Europe. It is the third-largest island in Europe and the twentieth-largest island on Earth...
,
ItalyItaly , officially the Italian Republic languages]] under the European Charter for Regional or Minority Languages. In each of these, Italy's official name is as follows:;;;;;;;;), is a unitary parliamentary republic in South-Central Europe. To the north it borders France, Switzerland, Austria and...
,
SpainSpain , officially the Kingdom of Spain languages]] under the European Charter for Regional or Minority Languages. In each of these, Spain's official name is as follows:;;;;;;), is a country and member state of the European Union located in southwestern Europe on the Iberian Peninsula...
, and
SwedenSweden , officially the Kingdom of Sweden , is a Nordic country on the Scandinavian Peninsula in Northern Europe. Sweden borders with Norway and Finland and is connected to Denmark by a bridge-tunnel across the Öresund....
. They disrupt the ecosystems by monotypic colonization, and damage harbors and waterways, ships and boats, and water treatment and power plants. Water treatment plants are most impacted because the water intakes bring the microscopic free-swimming larvae directly into the facilities. The Zebra Mussels also cling on to pipes under the water and clog them.
Grossinger reported it in
HungaryHungary , officially the Republic of Hungary , is a landlocked country in Central Europe. It is situated in the Carpathian Basin and is bordered by Slovakia to the north, Ukraine and Romania to the east, Serbia and Croatia to the south, Slovenia to the southwest and Austria to the west. The...
in 1794. Kerney and Morton described the rapid colonization of Britain by the zebra mussel, first in
CambridgeshireCambridgeshire is a county in England, bordering Lincolnshire to the north, Norfolk to the northeast, Suffolk to the east, Essex and Hertfordshire to the south, and Bedfordshire and Northamptonshire to the west...
in the 1820s, London in 1824, and in the
Union CanalThe Union Canal is a 31.5-mile canal in Scotland, from Lochrin Basin, Fountainbridge, Edinburgh to Falkirk, where it meets the Forth and Clyde Canal.-Location and features:...
near
EdinburghEdinburgh is the capital city of Scotland, the second largest city in Scotland, and the eighth most populous in the United Kingdom. The City of Edinburgh Council governs one of Scotland's 32 local government council areas. The council area includes urban Edinburgh and a rural area...
in 1834.
In 1827 zebra mussels were seen in the
NetherlandsThe Netherlands is a constituent country of the Kingdom of the Netherlands, located mainly in North-West Europe and with several islands in the Caribbean. Mainland Netherlands borders the North Sea to the north and west, Belgium to the south, and Germany to the east, and shares maritime borders...
at
RotterdamRotterdam is the second-largest city in the Netherlands and one of the largest ports in the world. Starting as a dam on the Rotte river, Rotterdam has grown into a major international commercial centre...
. Canals that artificially link many European waterways facilitated their early dispersal. It is non-indigenous in the Czech Republic in Elbe river in
BohemiaBohemia is a historical region in central Europe, occupying the western two-thirds of the traditional Czech Lands. It is located in the contemporary Czech Republic with its capital in Prague...
since 1893; in southern Moravia is probably native. Around 1920 the mussels reached Lake
MälarenLake Mälaren is the third-largest lake in Sweden, after Lakes Vänern and Vättern. Its area is 1,140 km² and its greatest depth is 64 m. Mälaren spans 120 kilometers from east to west...
in
SwedenSweden , officially the Kingdom of Sweden , is a Nordic country on the Scandinavian Peninsula in Northern Europe. Sweden borders with Norway and Finland and is connected to Denmark by a bridge-tunnel across the Öresund....
.
The first Italian appearance of the organism was in northern
ItalyItaly , officially the Italian Republic languages]] under the European Charter for Regional or Minority Languages. In each of these, Italy's official name is as follows:;;;;;;;;), is a unitary parliamentary republic in South-Central Europe. To the north it borders France, Switzerland, Austria and...
in
Lake GardaLake Garda is the largest lake in Italy. It is located in Northern Italy, about half-way between Brescia and Verona, and between Venice and Milan. Glaciers formed this alpine region at the end of the last ice age...
in 1973; in central Italy they appeared in
TuscanyTuscany is a region in Italy. It has an area of about 23,000 square kilometres and a population of about 3.75 million inhabitants. The regional capital is Florence ....
in 2003.
Zebra mussels are also present in British waterways. Many water companies are reporting having problems with their water treatment
plants with the mussels attaching themselves to pipeworks.
Anglian WaterAnglian Water is a privatised water company that operates in the East of England. Named for East Anglia, apart from Norfolk, Suffolk and Cambridgeshire it also covers Lincolnshire, Essex, Bedfordshire, Buckinghamshire, Northamptonshire, a small part of north Nottinghamshire and Greater London...
has estimated that it costs £500,000 to remove the mussels from their treatment plants.
North American invasion
In the U.S. and Canada, they were first detected in the
Great LakesThe Great Lakes are a collection of freshwater lakes located in northeastern North America, on the Canada – United States border. Consisting of Lakes Superior, Michigan, Huron, Erie, and Ontario, they form the largest group of freshwater lakes on Earth by total surface, coming in second by volume...
in 1988, in
Lake St. ClairLake St. Clair is a fresh-water lake named after Clare of Assisi that lies between the Province of Ontario and the State of Michigan, and its midline also forms the boundary between Canada and the United States of America. Lake St. Clair includes the Anchor Bay along the Metro Detroit coastline...
, located between
Detroit, MichiganDetroit is the major city among the primary cultural, financial, and transportation centers in the Metro Detroit area, a region of 5.2 million people. As the seat of Wayne County, the city of Detroit is the largest city in the U.S. state of Michigan and serves as a major port on the Detroit River...
, and
Windsor, OntarioWindsor is the southernmost city in Canada and is located in Southwestern Ontario at the western end of the heavily populated Quebec City – Windsor Corridor. It is within Essex County, Ontario, although administratively separated from the county government. Separated by the Detroit River, Windsor...
. It is believed they were inadvertently introduced into the lakes in the
ballastBallast is used in sailboats to provide moment to resist the lateral forces on the sail. Insufficiently ballasted boats will tend to tip, or heel, excessively in high winds. Too much heel may result in the boat capsizing. If a sailing vessel should need to voyage without cargo then ballast of...
water of ocean-going ships traversing the St. Lawrence Seaway. Another possible often neglected mode of introduction is on anchors and chains, although this has not been proven. Since adult zebra mussels can survive out of water for several days or weeks if the temperature is low and humidity is high, chain lockers provide temporary refuge for clusters of adult mussels that could easily be released when transoceanic ships drop anchor in freshwater ports. In 1990 almost every surface the zebra muscles could grow on they were on. They have become an
invasive species"Invasive species", or invasive exotics, is a nomenclature term and categorization phrase used for flora and fauna, and for specific restoration-preservation processes in native habitats, with several definitions....
in North America, and as such they are the target of Federal policy to control them, for instance in the National Invasive Species Act (1996).
As
zebra musselThe zebra mussel, Dreissena polymorpha, is a small freshwater mussel. This species was originally native to the lakes of southeast Russia being first described in 1769 by a German zoologist Peter Simon Pallas in the Ural, Volga and Dnieper rivers. They are still found nearby, as Pontic and Caspian...
s have also been known to attach themselves to the crayfish bait, this is one of the ways they have spread to different waterways.
By Location
From their first appearance in American waters in 1988, zebra mussels have spread to a large number of waterways, including
Lake SimcoeLake Simcoe is a lake in Southern Ontario, Canada, the fourth-largest lake wholly in the province, after Lake Nipigon, Lac Seul, and Lake Nipissing. At the time of the first European contact in the 17th century the lake was called Ouentironk by the Huron natives...
the Great Lakes region and the
MississippiThe Mississippi River is the largest river system in North America. Flowing entirely in the United States, this river rises in western Minnesota and meanders slowly southwards for to the Mississippi River Delta at the Gulf of Mexico. With its many tributaries, the Mississippi's watershed drains...
,
HudsonThe Hudson is a river that flows from north to south through eastern New York. The highest official source is at Lake Tear of the Clouds, on the slopes of Mount Marcy in the Adirondack Mountains. The river itself officially begins in Henderson Lake in Newcomb, New York...
, St. Lawrence,
OhioThe Ohio River is the largest tributary, by volume, of the Mississippi River. At the confluence, the Ohio is even bigger than the Mississippi and, thus, is hydrologically the main stream of the whole river system, including the Allegheny River further upstream...
,
CumberlandThe Cumberland River is a waterway in the Southern United States. It is long. It starts in Harlan County in far southeastern Kentucky between Pine and Cumberland mountains, flows through southern Kentucky, crosses into northern Tennessee, and then curves back up into western Kentucky before...
,
MissouriThe Missouri River flows through the central United States, and is a tributary of the Mississippi River. It is the longest river in North America and drains the third largest area, though only the thirteenth largest by discharge. The Missouri's watershed encompasses most of the American Great...
,
TennesseeThe Tennessee River is the largest tributary of the Ohio River. It is approximately 652 miles long and is located in the southeastern United States in the Tennessee Valley. The river was once popularly known as the Cherokee River, among other names...
,
ColoradoThe Colorado River , is a river in the Southwestern United States and northwestern Mexico, approximately long, draining a part of the arid regions on the western slope of the Rocky Mountains. The watershed of the Colorado River covers in parts of seven U.S. states and two Mexican states...
, and
ArkansasThe Arkansas River is a major tributary of the Mississippi River. The Arkansas generally flows to the east and southeast as it traverses the U.S. states of Colorado, Kansas, Oklahoma, and Arkansas. The river's initial basin starts in the Western United States in Colorado, specifically the Arkansas...
Rivers. Today the invasion continues, for instance in 2009, The Massachusetts Department of Conservation and Recreation confirmed that zebra mussels had been found in Laurel Lake in the Berkshires.
That same year the Minnesota Department of Natural Resources announced that live zebra mussels have been found in
Pelican Lake, MinnesotaPelican Lake is a lake located about seven miles north of Pelican Rapids, in Otter Tail County, Minnesota, United States. Pelican Lake is now a highly developed lake with its major uses being predominantly recreation, but its fishing is also excellent...
. This was the first confirmed sighting in the Red River Basin, which extends across the international border into the province of Manitoba. In July, 2010, the North Dakota Game and Fish Department confirmed the presence of zebra mussel veliger in the Red River between Wahpeton, N.D. and Breckenridge, Minnesota. As recently as 2010 California similarly reported invasions.
A common inference made by scientists predicts that the zebra mussel will continue spreading passively, by ship and by pleasure craft, to more rivers in North America. Trailered boat traffic is the most likely vector for invasion into Western North America. This spread is preventable if boaters thoroughly clean and dry their boats and associated equipment before transporting them to new bodies of water. Since no North American predator or combination of predators has been shown to significantly reduce zebra mussel numbers, such spread would most likely result in permanent establishment of zebra mussels in many North American
waterwayA waterway is any navigable body of water. Waterways can include rivers, lakes, seas, oceans, and canals. In order for a waterway to be navigable, it must meet several criteria:...
s.
Cost
The cost of fighting the pests at power plants and other water-consuming facilities is substantial, but the exact magnitude of the damage is a matter of some controversy. According to the Center for Invasive Species Research at the University of California, Riverside, the cost of management of Zebra mussel in the Great Lakes alone exceeds $500 million a year. A more conservative study estimated total economic costs of $267 million for electric generation and water treatment facilities in the entire United States from 1989 through 2004.
Effects of zebra mussels
Zebra mussels are
filter feederFilter feeders are animals that feed by straining suspended matter and food particles from water, typically by passing the water over a specialized filtering structure. Some animals that use this method of feeding are clams, krill, sponges, baleen whales, and many fish and some sharks. Some birds,...
s. When in the water, they open their shells to admit
detritusDetritus is a biological term used to describe dead or waste organic material.Detritus may also refer to:* Detritus , a geological term used to describe the particles of rock produced by weathering...
. As their shells are very sharp, they are known for cutting people's feet, resulting in the need to wear water shoes wherever they are prevalent.
Since their colonization of the
Great LakesThe Great Lakes are a collection of freshwater lakes located in northeastern North America, on the Canada – United States border. Consisting of Lakes Superior, Michigan, Huron, Erie, and Ontario, they form the largest group of freshwater lakes on Earth by total surface, coming in second by volume...
, they have covered the undersides of docks, boats, and anchors. They have also spread into streams and rivers nationwide. In some areas they completely cover the
substrateStream substrate is the material that rests at the bottom of a stream. There are several classification guides. One is:*Mud – silt and clay.*Sand – Particles between 0.06 and 2 mm in diameter.*Granule – Between 2 and 4 mm in diameter....
, sometimes covering other freshwater mussels. They can grow so densely that they block pipelines, clogging water intakes of municipal water supplies and
hydroelectricHydroelectricity is the term referring to electricity generated by hydropower; the production of electrical power through the use of the gravitational force of falling or flowing water. It is the most widely used form of renewable energy...
companies. Recent research has found that zebra mussels don't attach to
cupronickelCupronickel or copper-nickel or "cupernickel" is an alloy of copper that contains nickel and strengthening elements, such as iron and manganese. Cupronickel is highly resistant to corrosion in seawater, because its electrode potential is adjusted to be neutral with regard to seawater...
alloys, which can be used to coat intake and discharge grates, navigational buoys, boats, and motors where the species tend to congregate.
Zebra mussels are believed to be the source of deadly
avian botulismBotulism also known as botulinus intoxication is a rare but serious paralytic illness caused by botulinum toxin which is metabolic waste produced under anaerobic conditions by the bacterium Clostridium botulinum, and affecting a wide range of mammals, birds and fish...
poisoning that has killed tens of thousands of birds in the Great Lakes since the late 1990s.
They are also responsible for many species near extinction in certain areas of the great lake system like georgian bay they out work native species for food and grow on top of the native clams and mussels suffocating them
However, zebra mussels and other non-native species are credited with the increased population and size of
smallmouth bassThe smallmouth bass is a species of freshwater fish in the sunfish family of the order Perciformes. It is the type species of its genus...
in Lake Erie and
yellow perchThe yellow perch is a species of perch found in the United States and Canada, where it is often referred to by the shortform perch. Yellow perch look similar to the European perch, but are paler and more yellowish, with less red in the fins. They have six to eight dark, vertical bars on their sides...
in
Lake St. ClairLake St. Clair is a fresh-water lake named after Clare of Assisi that lies between the Province of Ontario and the State of Michigan, and its midline also forms the boundary between Canada and the United States of America. Lake St. Clair includes the Anchor Bay along the Metro Detroit coastline...
. They cleanse the waters of inland lakes, resulting in increased sunlight penetration and growth of native
algaeAlgae are a large and diverse group of simple, typically autotrophic organisms, ranging from unicellular to multicellular forms, such as the giant kelps that grow to 65 meters in length. They are photosynthetic like plants, and "simple" because their tissues are not organized into the many...
at greater depths. This cleansing also increases water visibility and filters out pollutants. Each quagga and zebra mussel filters about 1 USqt of water a day when confined to small tanks. In lakes, their filtering effects are usually spatially restricted (near the lake bottom) due to non-homogeneous water column mixing.
Further reading
- Minchin, D. 2003. The Zebra Mussel Dreissena polymopha (Pallas) extends its range westwards in Ireland. Bull. Ir. biogeog. Soc. 26: 176 - 18.
External links