Sander vitreus (walleye)
- Summary of Invasiveness
- Taxonomic Tree
- Distribution Table
- History of Introduction and Spread
- Risk of Introduction
- Habitat List
- Biology and Ecology
- Natural Food Sources
- Water Tolerances
- Means of Movement and Dispersal
- Pathway Causes
- Pathway Vectors
- Economic Impact
- Environmental Impact
- Social Impact
- Risk and Impact Factors
- Uses List
- Similarities to Other Species/Conditions
- Prevention and Control
- Links to Websites
- Distribution Maps
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PicturesTop of page
IdentityTop of page
Preferred Scientific Name
- Sander vitreus
Preferred Common Name
Other Scientific Names
- Lucioperca americana Cuvier, 1828
- Lucioperca grisea DeKay, 1842
- Perca fluviatilis (non Linnaeus, 1758)
- Perca vitrea Mitchill, 1818
- Sander vitreus glaucus Hubbs, 1926
- Stizostedion glaucum Hubbs, 1926
- Stizostedion vitreum (Mitchill, 1818)
- Stizostedion vitreum glaucum Hubbs, 1926
- Stizostedion vitreum vitreum (Mithchill, 1818)
International Common Names
- English: blue pike; dory; glass eye; gray pike; green pike; jack salmon; marble Eye; okow; pickerel; pike-perch; walleye; walleye pike; wall-eyed pickerel; walleyed pike; wall-eyed pike; wall-eyed pike-perch; yellow pickerel; yellow pike; yellow pike perch; yellow pike-perch; yellow walleye
- Spanish: lucioperca americana
- French: doré; doré jaune; Sandre américain
- Russian: svetloperyi sudak
Local Common Names
- Canada: pickerel; pike-perch; walleye; walleye pickerel; walleye pike; wall-eyed pickerel; wall-eyed pike; wall-eyed pike-perch; yellow pickerel; yellow pike; yellow pike perch; yellow walleye
- Denmark: blå sandart; hvidøjet sandart
- Finland: valkosilmäkuha; valkosilmäkuha
- France: doré
- Germany: Amerikanischer Zander; Amerikanischer Zander; Zander
- Poland: sandacz amerykanski; sandacz amerykanski
- Portugal: picão-verde; picão-verde
- Russian Federation: svetloperyi sudak
- Sweden: glasögongös
- UK: green pike; jack salmon; okow; walleyed pike; yellow pickerel; yellow pike
- USA: blue pike; dory; glass eye; gray pike; marble eye; pike-perch; walleye; yellow pike-perch
Summary of InvasivenessTop of page
Walleye, Sander vitreus, is a freshwater fish native to North America. The walleye has been intentionally stocked as a food fish and for sport fishing within North America for over a century. Natural migration, as well as walleye being flushed downstream during years of high water, has allowed this species to colonize many downstream sections of rivers in the western USA (McMillan, 1984).
The introduction of walleye has been shown to negatively affect other fish species through competition, predation, or by altering species composition. Juvenile walleye coexist with the young of a number of other fish species. McMahon (1992) suggested that competition would occur between walleye, perch and trout fry in the Canyon Ferry Reservoir where no thermal stratification would separate them. Through competition, the numbers and health of brown trout Salmo trutta were found to decrease after introduced walleyes consumed a large portion of the crayfish population, the brown trout’s main food source (McMahon and Bennett, 1996). When walleye were initially introduced into Salmon Falls Creek Reservoir, Idaho, yellow perch Perca flavescens comprised 80% of the sport fish. However, 12 years later, walleye made up 80% and perch only 1% of the fish in the reservoir (McMahon and Bennett, 1996). Walleye have been shown to prey on smolts of Pacific salmon and consume an estimated two million smolts annually in the Columbia River, thereby accounting for about one third of total predation loss of Pacific salmon smolts (McMahon and Bennett, 1996). A study in Seminoe Reservoir, Wyoming, found walleye stocking resulted in a sharp decline in native minnows Hybognathus spp., darters Etheostoma spp., suckers Catostomus spp., rainbow trout Oncorhynchus mykiss and crayfish Orconectes obscurus.
Taxonomic TreeTop of page
- Domain: Eukaryota
- Kingdom: Metazoa
- Phylum: Chordata
- Subphylum: Vertebrata
- Class: Actinopterygii
- Order: Perciformes
- Suborder: Percoidei
- Family: Percidae
- Genus: Sander
- Species: Sander vitreus
DescriptionTop of page
Walleye have a torpedo-shaped body, which ranges from dark olive brown to yellowish gold, and its sides are often marked with brassy flecks. The belly is whitish and paler than the back and sides. Ctenoid scales are extensive and well developed covering the back, sides, under-belly, and pectoral area. The opercular and preopercular areas are lightly scaled or naked (Hartman, 2009). The fins are well developed and contain spiny and soft rays. The two dorsal fins are clearly separated, with the anterior fin supported by 12 to 16 strong spines; the second dorsal is supported by one spine and 18 to 22 soft rays. The pectoral fins are rounded and without spines. The pelvic fins are supported by one spine and five rays (Scott and Crossman, 1973). The mouth is large and horizontal, with equal upper and lower jaws; the maxillary, forming the outer margin of the upper jaw, extends past the center of the eye. There are strong teeth on the maxillaries, premaxillaries, jaws, head of the vomer, and palatines. The canine teeth on the head of the vomer may be re-curved for effective predation. There are teeth on the inner and outer edges of the gill arches (Scott and Crossman, 1973). The head and teeth are well suited to predation. The head is armored with serrae on the preopercular bone and a spine on the opercle (Hartman, 2009).
Distribution TableTop of page
The distribution in this summary table is based on all the information available. When several references are cited, they may give conflicting information on the status. Further details may be available for individual references in the Distribution Table Details section which can be selected by going to Generate Report.
|Continent/Country/Region||Distribution||Last Reported||Origin||First Reported||Invasive||Reference||Notes|
|Canada||Present||Native||Scott and Crossman, 1973; Froese and Pauly, 2004|
|-Alberta||Widespread||Native||Scott and Crossman, 1973|
|-British Columbia||Present||Native||Scott and Crossman, 1973; Froese and Pauly, 2004|
|-Manitoba||Widespread||Native||Scott and Crossman, 1973|
|-Northwest Territories||Widespread||Native||Scott and Crossman, 1973|
|-Ontario||Widespread||Native||Scott and Crossman, 1973|
|-Quebec||Widespread||Native||Froese and Pauly, 2004|
|-Yukon Territory||Widespread||Native||Scott and Crossman, 1973|
|USA||Present||Native||Froese and Pauly, 2004|
|-Alabama||Widespread||Native||Page and Burr, 1991|
|-Arkansas||Widespread||Native||Page and Burr, 1991|
|-California||Localised||Introduced||Dill and Cordone, 1997|
|-Iowa||Localised||Introduced||Harlan et al., 1987|
|-Kentucky||Localised||Introduced||Burr and Warren, 1986|
|-Minnesota||Widespread||Native||Etnier and Starnes, 1993|
|-Missouri||Widespread||Native||Missouri Department of Conservation, 2008|
|-New Hampshire||Localised||Introduced||DeLorme, 1996|
|-New Jersey||Localised||Introduced||Nelson, 1890|
|-New Mexico||Localised||Introduced||DeLorme, 1998|
|-North Carolina||Widespread||Native||Etnier and Starnes, 1993|
|-Oregon||Localised||Introduced||Lee et al., 1980|
|-Pennsylvania||Widespread||Native||Etnier and Starnes, 1993|
|-South Carolina||Localised||Introduced||Lee et al., 1980|
|-South Dakota||Localised||Introduced||Bailey and Allum, 1962|
|-Tennessee||Widespread||Native||Etnier and Starnes, 1993|
|-Vermont||Localised||Introduced||Lee et al., 1980|
|-Virginia||Localised||Introduced||Lee et al., 1980|
|-Washington||Localised||Introduced||Lee et al., 1980|
|-West Virginia||Localised||Introduced||Stauffer et al., 1995|
|-Wisconsin||Widespread||Native||Barron et al., 2000|
History of Introduction and SpreadTop of page
Walleye has been intentionally stocked as a food fish and for sport fishing within North America for over a century. One of the earliest recorded introductions occurred in 1874 when a small number of adult walleye were transported from Vermont to California, where the fish were released into the Sacramento River (Smith, 1896). Walleye have also been introduced into California as a biological control to help control nuisance species such as carp and bluegill as early as 1959 (Dill and Cordone, 1997). There is also a history of accidental introductions due to walleye being stocked instead of yellow perch Perca flavescens (Linder, 1963). The frequency of illegal introductions is also a growing issue in the Western States of America (McMahon and Bennett, 1996). Welcomme (1988) reported that walleye were accidentally introduced into the inland waters of the UK, but this population failed to establish. It has more recently been introduced into China for aquaculture purposes (Ma et al., 2003).
Risk of IntroductionTop of page
Throughout the history of this species’ introductions, walleye has been introduced into lakes and reservoirs predominantly as a sport fisheries target as well as a food fish; however, colonization of new waters beyond the point of release is a major concern, and regardless of many US state agencies initiating detailed environmental reviews to evaluate the risks and benefits of proposed introductions, illegal introductions of walleye continue (Vashro, 1990; 1995). Natural migration, as well as walleye being flushed downstream during years of high water, has allowed this species to colonize many downstream sections of rivers in the western USA (McMillan, 1984).
HabitatTop of page
Walleye generally prefer large (>100 ha), cool water bodies with a gravel and sandy substrate and with high turbidity. This species occurs in lakes, pools, backwaters and runs of medium to large rivers (Etnier and Starnes, 1993; Frimodt, 1995). They prefer areas with extensive littoral areas and large areas of rocky substrate. Ideally, 25-45% of surface area should provide cover in the way of boulders, logs, brush and vegetation (Scott and Crossman, 1973; McMahon et al., 1984).
Habitat ListTop of page
|Inland saline areas||Present, no further details||Natural|
|Rivers / streams||Principal habitat||Natural|
Biology and EcologyTop of page
Walleye has a diploid (2n) chromosome number of 48 and a haploid/gametic (n) of 24 (Danzmann, 1979). The genetics of this species has been intensively studied (April et al., 2011). It is also known to hybridize in nature with sauger (Sander canadense) (Scott and Crossman, 1973; Billington and Koigi, 2003).
Walleye are broadcast spawners, usually preferring shallow shorelines and riffle areas with good water circulation for spawning on gravel shoals (Scott and Crossman, 1973; McMahon et al., 1984). The spawning act usually involves 1-2 female and 2-6 male fish. The spawning group rushes near to the surface in shallow water, where eggs and sperm are released (Ellis and Giles, 1965; Scott and Crossman, 1973). Females release 200 to 300 eggs at a time, as often as every five minutes. Eggs eventually settle to the bottom and fall into crevices in the substrate. Most spawning activity takes place at night, although spawning does occur during daylight hours. Many walleye populations are known to migrate to rivers or tributary streams characterized by fast flowing water and gravel-coarse rock substrates. Walleye also spawn on lake shoals. In some inland lakes, shoal spawning may actually occur under the ice (Dimond et al., 1996).
Walleyes may be infected with a wide range of diseases and parasites. Protozoan parasites that infect walleye include Ichthyoptirius multillis, Myxosporidia, copepod parasites including the many species of fish lice, and Ergasilus centrachidarum (Hartman, 2009). Three genera of nematode, Contracaecum sp. Eustrongylides sp. and Rhaphidascaris sp., and one species of acanthocephalan, Neoechinorhynchus tenellum, also parasitize walleyes (Dechtiar, 1972). Four genera of cestodes have also been identified as walleye parasites: Bothriocephalus sp., Proteocephalus sp., Triaenophorus sp. and Diphyllobothrium sp. (Poole and Dick, 1985).
The monogenean flukes Cleidodiscus aculeatus and Urocleidus aculeatus are external parasites that infect walleye. Walleye are susceptible to several bacterial diseases such as Columnaris disease. Lymphocistis is a common viral disease among walleye (Hartman, 2009).
Walleye have a relatively wide range of environmental tolerances, with an upper temperature range of 29-34°C and a preferred range of 20-24°C in summer (DFO, 2011). This species is able to tolerate low oxygen (to 2 mg·L-1) but prefers levels greater than 5 mg·L-1. Suitable lakes are usually >400 ha, with large littoral zones.
Natural Food SourcesTop of page
|Food Source||Life Stage||Contribution to Total Food Intake (%)||Details|
|Catostomus commersoni||All Stages|
ClimateTop of page
|D - Continental/Microthermal climate||Preferred||Continental/Microthermal climate (Average temp. of coldest month < 0°C, mean warmest month > 10°C)|
|Df - Continental climate, wet all year||Preferred||Continental climate, wet all year (Warm average temp. > 10°C, coldest month < 0°C, wet all year)|
|Ds - Continental climate with dry summer||Preferred||Continental climate with dry summer (Warm average temp. > 10°C, coldest month < 0°C, dry summers)|
|Dw - Continental climate with dry winter||Preferred||Continental climate with dry winter (Warm average temp. > 10°C, coldest month < 0°C, dry winters)|
Water TolerancesTop of page
|Parameter||Minimum Value||Maximum Value||Typical Value||Status||Life Stage||Notes|
|Dissolved oxygen (mg/l)||>5mg/l||Optimum|
|Water pH (pH)||6.0||9.0||Optimum||5.0-9.5 tolerated. Hartman 2009|
|Water temperature (ºC temperature)||20||24||Optimum||0.1-34 McMahon et al. 1984|
Means of Movement and DispersalTop of page
Natural Dispersal (Non-Biotic)
Species migrates during the spawning season.
There is a history of accidental introductions due to misidentification, with the walleye being stocked instead of yellow perch Perca flavescens (Linder, 1963).
Walleye have a long history of introductions outside of its native range, mainly as an angling target, but also more recently as an aquacultural species (see History of Introduction and Spread).
Pathway CausesTop of page
|Aquaculture||See distribution table and list||Yes||Yes|
|Biological control||See distribution table and list||Yes||Yes|
|Fisheries||See distribution table and list||Yes||Yes|
|Flooding and other natural disasters||See distribution table and list||Yes||Yes|
|Food||See distribution table and list||Yes||Yes|
|Hunting, angling, sport or racing||See distribution table and list||Yes||Yes|
|Intentional release||See distribution table and list||Yes||Yes|
Pathway VectorsTop of page
Economic ImpactTop of page
The walleye is probably the most economically important sport and commercial species in Ontario and the Prairie Provinces. It is a major species in Quebec’s recreational fishery (Fisheries and Oceans Canada, 2005). Although not a commercial species in the US, it is highly esteemed there.
Environmental ImpactTop of page
Impact on Biodiversity
Walleye are able to hybridise with sauger (Sander canadensis). The main impacts on biodiversity are through alteration of fish communities through predation (i.e. cyprinids or salmonids) and competition with other fish species (i.e. bass).
Social ImpactTop of page
Throughout North America, the walleye is a highly sought after recreational fishing species as well as commercially in Canada. In addition to its value for commercial fishermen, recreational fishing and tourism may create a demand not only for food, accommodation and transportation, but also for related recreational activities such as camping, boating, canoeing, etc. all of which may provide economic opportunities locally.
Risk and Impact FactorsTop of page Invasiveness
- Invasive in its native range
- Proved invasive outside its native range
- Has a broad native range
- Abundant in its native range
- Highly adaptable to different environments
- Tolerant of shade
- Capable of securing and ingesting a wide range of food
- Highly mobile locally
- Long lived
- Altered trophic level
- Damaged ecosystem services
- Ecosystem change/ habitat alteration
- Negatively impacts aquaculture/fisheries
- Reduced native biodiversity
- Threat to/ loss of endangered species
- Threat to/ loss of native species
- Competition - monopolizing resources
- Pest and disease transmission
- Highly likely to be transported internationally accidentally
- Highly likely to be transported internationally deliberately
- Highly likely to be transported internationally illegally
- Difficult/costly to control
Uses ListTop of page
- Biological control
- Sport (hunting, shooting, fishing, racing)
Human food and beverage
- Meat/fat/offal/blood/bone (whole, cut, fresh, frozen, canned, cured, processed or smoked)
Similarities to Other Species/ConditionsTop of page
Sauger (Sander canadensis) is similar to walleye in appearance but has a more limited North American distribution. The sauger is smaller and more slender than the walleye. Its dorsal fin, unlike the walleye's, is marked by rows of dark spots and lacks the dark blotch at the rear base. The sauger also lacks the white lower tail tip.
Prevention and ControlTop of page
Rapid response is established at the national level.
There is not much awareness of the species’ invasiveness and walleye are still stocked.
Montana Fish, Wildlife and Parks are currently proposing a 6-year effort to investigate suppressing illegally introduced walleye in the Noxon Reservoir by using a variety of sampling gear and techniques; however, no proven methods have yet been found.
As established populations are difficult and costly to control, further introductions or stocking should be avoided.
Electrofishing and seine netting.
There are some regional regulations. Movement control could be improved by increased public awareness.
The only effective method of fish eradication is the application of rotenone, a piscicide that is also toxic to non target species.
Monitoring and Surveillance (incl. Remote Sensing)
Both radio and acoustic telemetry can be used.
ReferencesTop of page
April J; Mayden RL; Hanner RH; Bernatchez L, 2011. Genetic calibration of species diversity among North America's freshwater fishes. Proceedings of the National Academy of Sciences of the United States of America, 108(26):10602-10607.
Bailey RM; Allum MO, 1962. Fishes of South Dakota. Michigan, USA: Miscellaneous Publications, Museum of Zoology, University of Michigan, 119.
Barron MG; Anderson MJ; Cacela D; Lipton J; The SJ; Hinton DE; Zelikoff JT; Dikkeboom AL; Tillitt DE; Holey M; Denslow N, 2000. PCBs, liver lesions and biomarker responses in adult walleye (Stizostedium vitreum vitreum) collected from Green Bay, Wisconsin. Journal of Great Lakes Research, 26:250-771.
Billington N; Koigi RN, 2003. Hybridization between sauger and walleye in Lewis and Clark Lake, South Dakota, determined by protein electrophoresis. In: Proceedings of PERCIS III, the Third International Fish Symposium [ed. by Barry, T. P. \Malison, J. A.]. Madison, Wisconsin, USA: University of Wisconsin, 101-102.
Burr BM; Warren ML, 1986. A Distributional Atlas of Kentucky Fishes (A Distributional Atlas of Kentucky Fishes.). Frankfort, Kentucky, USA: Kentucky State Nature Preserves Commission, 398 pp. [Kentucky State Nature Preserves Commission Scientific and Technical Series Number 4.]
Dechtiar AO, 1972. New parasite records for Lake Erie fish. Great Lakes Fishery Comission Technical Report Series, 17:26 pp.
DeLorme, 1992. Idaho Atlas and Gazatteer. Freeport, Maine, USA: DeLorme Mapping Company, 63 pp.
DeLorme, 1995. Virginia Atlas and Gazatteer. Yarmouth, Maine, USA: DeLorme Mapping Company.
DeLorme, 1996. New Hampshire Atlas and Gazatteer. Yarmouth, Maine, USA: DeLorme.
DeLorme, 1998. Georgia Atlas and Gazatteer. Yarmouth, Maine, USA: DeLorme Mapping Company.
DeLorme, 1999. Connecticut/Rhode Island Atlas and Gazatteer. Yarmouth, Maine, USA: DeLorme Mapping Company.
DFO, 2011. Science Advice from a Risk Assessment of Walleye (Sander vitreus) in British Columbia. Scientific Advisory Secretariat Report, 86., Canada: DFO Canada.
Dill WA; Cordone AJ, 1997. History and status of introduced fises in California, 1871-1996. Fish Bulletin, 178.
Dimond PE; Dextrase AJ; Lester NP, 1996. Stress histories of selected Ontario walleye waters. Percid Community Synthesis:45 pp.
Douglas NH, 1974. Freshwater fishes of Louisiana. Baton Rouge, Louisiana, USA: Claitor's Publishing Division.
Ellis DV; Giles MA, 1965. The spawning behavior of the walleye, Stizostedion vitreum (Mitchill). Transactions of the American Fisheries Society, 94:358-362.
Fisheries and Oceans Canada, 2005. Fisheries and Oceans Canada. Quebec, Canada: Fisheries and Oceans Canada (online). http://www.dfo-mpo.gc.ca/index-eng.htm
Froese R; Pauly D, 2004. FishBase DVD. Penang, Malaysia: Worldfish Center. Online at www.fishbase.org.
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Linder AD, 1963. Idaho's alien fishes. Journal of the Idaho Museum of Natural History, 6(2):12-15.
Ma X; Bangxi X; Yindong W; Mingxue W, 2003. Intentionally introduced and transferred fishes in China's inland waters. Asian Fisheries Science, 16(3,4):279-290.
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McMahon TE, 1992. Potential impacts of the introduction of walleye to the fishery of Canyon Ferry Reservoir and adjacent waters. Potential impacts of the introduction of walleye to the fishery of Canyon Ferry Reservoir. Helena, Montana, USA: Montana Department of Fish, Wildlife and Parks, 56 pp.
McMahon TE; Bennett DH, 1996. Walleye and northern pike: boost or bane to northwest fisheries? Fisheries, 21(8):6-13.
McMahon TE; Terrell JW; Nelson PC, 1984. Habitat suitability information walleye., USA: Division of Biological Services, Research and Development, US Fish and Wildlife Service.
McMillan J, 1984. Evaluation and enhancement of the trout and walleye fisheries in the North Platte River system of Wyoming. Laramie, Wyoming, USA: Wyoming Game and Fish Department.
Missouri Department of Conservation, 2008. Fish of Missouri. Missouri, USA: Missouri Department of Conservation. http://mdc.mo.gov/
Near TJ, 2002. Phylogenetic relationships of Percina (Percidae: Etheostomatinae). Copeia, 2002(1):1-14.
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Rasmussen JL, 1998. Aquatic nuisance species of the Mississippi river basin. In: 60th Midwest Fish and Wildlife Conference, Aquatic Nuisance Species Symposium, Dec. 7, 1998, Cincinnati, OH. unpaginated.
Robinson HW; Buchanan TM, 1988. Fishes of Arkansas. Arkansas, USA: University of Arkansas Press, 536.
Scott WB; Crossman EJ, 1973. Freshwater fishes of Canada. Bull. Fish. Res. Board Can. 184:1-966.
Smith HM, 1896. A review of the history and results of the attempts to acclimatize fish and other water animals in the Pacific states. Bulletin of the United States Fish Commission, 15:379-472.
Vashro J, 1990. Illegal aliens. Montana Outdoors, 21(4). Helena, Montana, USA: Montana Fish, Wildlife and Parks, 35-37.
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ContributorsTop of page
01/04/13 Original text by:
Michael Godard, consultant, UK
Distribution MapsTop of page
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