Common names for S. glanis are wels catfish or sheatfish.
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.
Perception Channels: tactile ; chemical
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.
US Federal List: no special status
CITES: no special status
IUCN Red List of Threatened Species: least concern
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.
Silurus glanis introductions have been implicated in declining populations of other commercial fishes.
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.
Positive Impacts: food
Silurus glanis carry bacterial diseases that can be transmitted to other fish. They are important predators of fish, crustaceans, small mammals, and aquatic birds.
Commensal/Parasitic Species:
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.
Animal Foods: birds; mammals; amphibians; reptiles; fish; carrion ; insects; mollusks; terrestrial worms; aquatic crustaceans; zooplankton
Plant Foods: phytoplankton
Primary Diet: carnivore (Eats terrestrial vertebrates, Piscivore ); planktivore
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.
Biogeographic Regions: palearctic (Introduced , Native )
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.
Range depth: 0 to 30 m.
Habitat Regions: temperate ; freshwater
Aquatic Biomes: lakes and ponds; rivers and streams; brackish water
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.
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.
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.
Range mass: 220 (high) kg.
Average mass: 45 kg.
Range length: 3 (high) m.
Average length: 1.3-1.6 m.
Other Physical Features: ectothermic ; heterothermic ; bilateral symmetry
Sexual Dimorphism: sexes alike
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.
Known Predators:
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.
Breeding interval: Wels catfish breed annually during the spring.
Breeding season: Breeding/spawning season runs from May through July.
Range gestation period: 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 (male): 3 years.
Key Reproductive Features: iteroparous ; seasonal breeding ; gonochoric/gonochoristic/dioecious (sexes separate); sexual ; fertilization (External ); oviparous
Average age at sexual or reproductive maturity (male)
Sex: male: 912 days.
Average age at sexual or reproductive maturity (female)
Sex: female: 1277 days.
The male protects the eggs until they hatch.
Parental Investment: pre-fertilization (Provisioning, Protecting: Female); pre-hatching/birth (Protecting: Male)
