Animal Diversity Web

Ge­o­graphic Range

Sil­u­rus gla­nis, sheat­fish or wels cat­fish, is na­tive to east­ern Eu­rope and Asia. It has been in­tro­duced to sev­eral other areas in­clud­ing Ger­many, France, Spain, Eng­land, Greece, Turkey and the Nether­lands. (Black, Predator-fishing.​co.​uk 2005)

• Biogeographic Regions
• palearctic
  • introduced
  • native

Habi­tat

Sil­u­rus gla­nis is found pri­mar­ily in large rivers and lakes and in deep water near dams. These cat­fish some­times enter brack­ish water in the Black Sea and Baltic Sea. (Froese and Pauly, 2005)

• Habitat Regions
• temperate
• freshwater

• Aquatic Biomes
• lakes and ponds
• rivers and streams
• brackish water

• Range depth

  0 to 30 m

  0.00 to 98.43 ft

Phys­i­cal De­scrip­tion

The elon­gated, scale­less body has a strong upper body and a lat­er­ally flat­tened tail. Sil­u­rus gla­nis varies in color. The upper side is usu­ally a dark color and the flanks and belly are more pale. The fins are brown­ish. The body has a mot­tled ap­pear­ance that is some­times ac­com­pa­nied by brown spots. These cat­fish can grow to be quite large, per­haps as large as 3 me­ters long. A max­i­mum re­ported weight was 220 kg. Most in­di­vid­u­als reach sizes be­tween 1.3 and 1.6 me­ters. Sil­u­rus gla­nis reach an av­er­age of 45 kg and has been con­sid­ered one of the largest fresh­wa­ter fish in its range.

Sil­u­rus gla­nis in­di­vid­u­als have 1 dor­sal spine and 4 to 5 dor­sal soft rays, 1 anal spine and 90 to 94 anal soft rays, and a cau­dal fin with 17 rays. They have paired pec­toral fins with 1 spine and 14 to 17 soft rays each. Their paired pelvic fins are po­si­tioned be­hind the dor­sal fin with 1 spine each and 11 to 12 soft rays each.

There are sev­eral mem­bers in the fam­ily Sil­uri­dae. Sil­u­rus gla­nis is dis­tin­guished by its smaller dor­sal fin, only two pairs of bar­bels, and the cau­dal fin being dis­tinct from the anal fin.

Sex can be de­ter­mined by the flap of skin be­hind the vent, in males it is thin and comes to a point, fe­males have a thicker and shorter flap of skin. (Black, Predator-fishing.​co.​uk 2005; Froese and Pauly, 2005)

• Other Physical Features
• ectothermic
• heterothermic
• bilateral symmetry

• Sexual Dimorphism
• sexes alike

• Range mass

  220 (high) kg

  484.58 (high) lb

• Average mass

  45 kg

  99.12 lb

• Range length

  3 (high) m

  9.84 (high) ft

• Average length

  1.3-1.6 m

  ft

De­vel­op­ment

The lar­vae hatch in ap­prox­i­mately 3 days, mea­sur­ing around 7 mm, and begin feed­ing on plank­ton. These fish grow quickly and can reach be­tween 1.5 and 4.5 kg in their first year. (ALP, et al., 2004; Black, Predator-fishing.​co.​uk 2005; )

Re­pro­duc­tion

There is lit­tle known about mat­ing be­hav­ior in this species. Males cre­ate nests where fe­males de­posit their eggs. Males then guard the eggs until they hatch.

• Mating System
• polygynandrous (promiscuous)

The male cre­ates a shal­low de­pres­sion that will hold thou­sands of eggs laid by the fe­male. The eggs are pro­tected by the male until they hatch. Fe­males can lay about 30,000 eggs per kilo­gram of body weight. Males grow faster and ma­ture ear­lier than fe­males. One study found that males ma­tured at 78.82 cm at age 3 and fe­males ma­tured at 87.05 cm at age 4. (Black, Predator-fishing.​co.​uk 2005)

• Key Reproductive Features
• iteroparous
• seasonal breeding
• gonochoric/gonochoristic/dioecious (sexes separate)
• sexual
• fertilization
  • external
• oviparous

• Breeding interval

  Wels catfish breed annually during the spring.

• Breeding season

  Breeding/spawning season runs from May through July.

• Range time to hatching

  3 to 10 days

• Range time to independence

  3 to 10 days

• Average age at sexual or reproductive maturity (female)

  4 years

• Average age at sexual or reproductive maturity (female)
  Sex: female

  1277 days

  AnAge

• Average age at sexual or reproductive maturity (male)

  3 years

• Average age at sexual or reproductive maturity (male)
  Sex: male

  912 days

  AnAge

The male pro­tects the eggs until they hatch. (Black, Predator-fishing.​co.​uk 2005)

• Parental Investment
• pre-fertilization
  • provisioning
  • protecting
    • female
• pre-hatching/birth
  • protecting
    • male

Lifes­pan/Longevity

The longest know lifes­pan in the wild is 80 years old for S. gla­nis. The ex­pected lifes­pan in the wild is as high as 20 to 30 years old. (Black, Predator-fishing.​co.​uk 2005; Froese and Pauly, 2005)

• Range lifespan
  Status: wild

  80 (high) years

• Typical lifespan
  Status: wild

  20 to 30 years

• Average lifespan
  Status: wild

  20 to 30 years

• Average lifespan
  Status: captivity

  60 years

  AnAge

Be­hav­ior

Sil­u­rus gla­nis is a soli­tary species that prefers still wa­ters, usu­ally with a soft bot­tom like mud. They may live in river bed holes under over­hangs of banks, or under other ob­struc­tions on river or lake beds such as sunken trees. These fish are most ac­tive at night and can tol­er­ate brack­ish water. (Kirsten Pohlmann, et al., 2001)

• Key Behaviors
• natatorial
• nocturnal
• motile
• solitary

Home Range

Noth­ing is known about home range sizes or pat­terns of move­ment in these cat­fish.

Com­mu­ni­ca­tion and Per­cep­tion

Sil­u­rus gla­nis in­di­vid­u­als use their bar­bels and ol­fac­tory buds to sense chem­i­cal cues in the water. They are thought to be ex­tra­or­di­nar­ily sen­si­tive to chem­i­cal stim­uli. They also have a lat­eral line sys­tem that helps them de­tect water move­ment. Sil­u­rus gla­nis in­di­vid­u­als may use path analy­sis to track prey. One study found that S. gla­nis can track the three-di­men­sional swim path of a guppy and suc­cess­fully at­tack it with­out the pres­ence of light. Lit­tle is known about com­mu­ni­ca­tion in these mainly soli­tary an­i­mals. (Bridge­man, Predator-fishing.​co.​uk 2005)

• Perception Channels
• tactile
• chemical

Food Habits

Sil­u­rus gla­nis fry feed on plank­ton dur­ing their first year of life. When they reach larger sizes they begin to eat worms, snails, crus­taceans, aquatic in­sects, and small fish. At adult sizes they will also prey on ducks, voles, cray­fish, fish, eels, frogs, rats, coypu, and snakes. They use the in­cred­i­ble suc­tion cre­ated by sud­denly open­ing their large mouths to take in prey.

Both the top and bot­tom jaws each have hun­dreds of in­ward slop­ing, soft teeth used to grip prey. There are two "crush­ing plates" in front of the throat cav­ity used to crush prey be­fore swal­low­ing. Sil­u­rus gla­nis ma­nip­u­late their prey prior to con­sump­tion by using sev­eral short spikes along the edge of the gill rak­ers. (Black, Predator-fishing.​co.​uk 2005)

• Primary Diet
• carnivore
  • eats terrestrial vertebrates
  • piscivore
• planktivore

• Animal Foods
• birds
• mammals
• amphibians
• reptiles
• fish
• carrion
• insects
• mollusks
• terrestrial worms
• aquatic crustaceans
• zooplankton

• Plant Foods
• phytoplankton

Pre­da­tion

North­ern pike (Esox lu­cius) and hu­mans are two preda­tors of Sil­u­rus gla­nis. Their large size pro­tects adults from many preda­tors. Smaller fish may be pro­tected some­what by their dor­sal spines. (Froese and Pauly, 2005)

• Known Predators

  • northern pike (Esox lucius)
  • humans (Homo sapiens)

Ecosys­tem Roles

Sil­u­rus gla­nis carry bac­te­r­ial dis­eases that can be trans­mit­ted to other fish. They are im­por­tant preda­tors of fish, crus­taceans, small mam­mals, and aquatic birds. (Farkas and Szitóné, 1986; Farkas, 1985)

Eco­nomic Im­por­tance for Hu­mans: Pos­i­tive

Sil­u­rus gla­nis is a com­mer­cial fish con­sumed by hu­mans. This fish has bone­less white flesh that is low in fat and highly palat­able. Tech­no­log­i­cal re­search for ar­ti­fi­cial re­pro­duc­tion, pop­u­la­tion ge­net­ics and con­ser­va­tion prob­lems have been de­vel­oped over the past 10 years in the Czech Re­pub­lic, France and other Eu­ro­pean coun­tries. It is also a val­ued game fish in Eu­ro­pean coun­tries. (Froese and Pauly, 2005; Lin­hart, et al., 2002)

• Positive Impacts
• food

Eco­nomic Im­por­tance for Hu­mans: Neg­a­tive

Sil­u­rus gla­nis in­tro­duc­tions have been im­pli­cated in de­clin­ing pop­u­la­tions of other com­mer­cial fishes. (Froese and Pauly, 2005)

Con­ser­va­tion Sta­tus

Sil­u­rus gla­nis pop­u­la­tions ap­pear to be sta­ble. They are pro­tected by Ap­pen­dix III of the Bern Con­ven­tion. In areas where these fish have been in­tro­duced, neg­a­tive eco­log­i­cal con­se­quences have been noted. (Froese and Pauly, 2005)

• IUCN Red List

  Least Concern
  More information

• IUCN Red List

  Least Concern
  More information

• US Federal List

  No special status

• CITES

  No special status

Other Com­ments

Com­mon names for S. gla­nis are wels cat­fish or sheat­fish. (Lin­hart, et al., 2002)

Con­trib­u­tors

Tanya Dewey (ed­i­tor), An­i­mal Di­ver­sity Web.

CAR­RIE SLONE (au­thor), East­ern Ken­tucky Uni­ver­sity, Sherry Har­rel (ed­i­tor, in­struc­tor), East­ern Ken­tucky Uni­ver­sity.

Ref­er­ences

ALP, A., C. KARA, H. BUYUKUA­PAR. 2004. Re­pro­duc­tive Bi­ol­ogy in a Na­tive Eu­ro­pean Cat­fish, Sil­u­rus gla­nis. Turkey Jour­nal of Vet­eri­nary An­i­mal Sci­ence, 28: 613-622. Ac­cessed De­cem­ber 07, 2005 at http://​journals.​tubitak.​gov.​tr/​veterinary/​issues/​vet-04-28-3/​vet-28-3-24-0303-29.​pdf.

Black, A. Predator-fishing.​co.​uk 2005. "Sil­uri­dae" (On-line). Ac­cessed Oc­to­ber 31, 2005 at http://​www.​predator-fishing.​co.​uk/​articles/​essay.​htm.

Bridge­man, G. Predator-fishing.​co.​uk 2005. "The 'Old World' cat­fish, Silurus.​glanis; it's evo­lu­tion­ary suc­cess story and un­ri­valled feed­ing strat­egy" (On-line). Ac­cessed Oc­to­ber 31, 2005 at http://​www.​predator-fishing.​co.​uk/​articles/​outwiththeold.​htm.

DOGAN BORA, N., A. GUL. 2004. Feed­ing Bi­ol­ogy of Sil­u­rus gla­nis (L., 1758). Turkey Jour­nal of Vet­eri­nary An­i­mal Sci­ence, 28: 471-479. Ac­cessed De­cem­ber 07, 2005 at http://​journals.​tubitak.​gov.​tr/​veterinary/​issues/​vet-04-28-3/​vet-28-3-3-0208-17.​pdf.

Farkas, J. 1985. Fil­a­men­tous Flavobac­terium sp. iso­lated from fish with gill dis­eases in cold water. Aqua­cul­ture, Vol­ume 44, Issue 1: 1-10. Ac­cessed No­vem­ber 01, 2005 at http://​www.​sciencedirect.​com/​science?_​ob=ArticleURL&_​aset=V-WA-A-W-WC-MsSAYZA-UUA-U-AABBVCECUZ-AABAUVUBUZ-VVVVYWDYC-WC-U&_​rdoc=21&_​fmt=summary&_​udi=B6T4D-49NPK1V-XH&_​coverDate=01%2F15%2F1985&_​cdi=4972&_​orig=search&_​st=13&_​sort=d&​view=c&_​acct=C000043360&_​version=1&_​urlVersion=0&_​userid=4159506&​md5=d2cb75770e5fd2588d18061914f5a4c3.

Farkas, J., M. Szitóné. 1986. Vib­rio dis­ease of sheat­fish (Sil­u­rus gla­nis L.) fry. Aqua­cul­ture, Vol­ume 51, Issue 2: 81-88. Ac­cessed No­vem­ber 01, 2005 at http://​www.​sciencedirect.​com/​science?_​ob=ArticleURL&_​aset=V-WA-A-W-WC-MsSAYZA-UUA-U-AABBVCECUZ-AABAUVUBUZ-VVVVYWDYC-WC-U&_​rdoc=20&_​fmt=summary&_​udi=B6T4D-49NXD4X-1SC&_​coverDate=01%2F01%2F1986&_​cdi=4972&_​orig=search&_​st=13&_​sort=d&​view=c&_​acct=C000043360&_​version=1&_​urlVersion=0&_​userid=4159506&​md5=1be4cd970b7851ee99258854225eb8d9.

Froese, R., D. Pauly. 2005. "Sil­u­rus gla­nis" (On-line). Ac­cessed Oc­to­ber 31, 2005 at http://​fishbase.​org/​Summary/​speciesSummary.​php?​ID=289&​genusname=Silurus&​speciesname=glanis.

Kirsten Pohlmann, , Frank W. Grasso, Thomas Bre­i­thaupt. 2001. Track­ing wakes: The noc­tur­nal preda­tory strat­egy of pis­civ­o­rous cat­fish. Pro­ceed­ings of the Na­tional Acad­emy of Sci­ences of the United States of Amer­ica, June 19; 98(13): 7371–7374. Ac­cessed Oc­to­ber 31, 2005 at http://​www.​pubmedcentral.​nih.​gov/​articlerender.​fcgi?​artid=34675.

Lin­hart, O., L. Stech, J. Svarc, M. Ro­d­ina, J. Au­de­bert, J. Grecu, R. Bil­lard. 2002. The cul­ture of the Eu­ro­pean cat­fish, Sil­u­rus gla­nis, in the Czech. Aquatic Liv­ing Re­sources, 15: 139-144. Ac­cessed De­cem­ber 08, 2005 at http://​www.​edpsciences.​org/​articles/​alr/​pdf/​2002/​02/​alr2099.​pdf?​access=ok.