William Yarrell (1836) in "A History of British Fishes":
| Silurus | glanis, | LINNĈUS. | ||
| " | " | Sheat fish, | BLOCH, pt. i. pl. 34. | |
| " | " | Sly Silurus, | STEWART's Nat. Hist. vol. i. p. 354. | |
| " | " | " | JENYNS, Syst. Cat. p. 27. | |
D. 5 : P. 18 : V. 13 : A. 24 : C. 17.
This fish is found not only in almost all the fresh waters of Europe, but even in those of Africa and Asia. Pliny states that it exists in the Nile. Bloch mentions that examples weighing from seventy to eighty pounds' weight have been taken in canals near Berlin. It has been found of very large size in the Wolga and the Danube, and is included by Nillson and others among the fishes of Norway and Sweden. It is found also, though rarely, in the sea, and has been taken in the Baltic.
Dr. Smith includes this species of Silurus in his Natural History of the Fishes of Massachusets ;* and mentions that Dr. Flint of Boston, an accurate naturalilst, had seen speci-mens measuring eight feet in length in the Ohio and Mississippi rivers.
The Silurus is represented as sluggish in its habits, and a slow swimmer, taking its prey by lying in wait for it, in a manner somewhat similar to the Angler, Lophius already described ; hiding itself in holes or soft mud, and apparently depending upon the accidental approach of fishes or other animals, of which its long and numerous barbules may be at the same time the source of attraction to the victims, and the means of warning to the devourer. From its own formidable size, it can have but few enemies in the fresh water ; and from them its dark colour, in addition to its habit of secreting itself either in holes or soft mud, would be a sufficient security. In spring, the male and female may be seen together, about the middle of the day, near the banks or edges of the water, but soon return to their usual retreats. The ova when deposited are green ; and the young are excluded between the sixteenth and nineteenth days.
The flesh of the Silurus is white, fat, and agreeable to many persons as food, particularly the part of the fish near the tail ; but on account of its being luscious, soft, and difficult to digest, it is not recommended to those who have weak stomachs. In the Northern countries of Europe, the flesh is preserved by drying, and the fat is used as lard.
The two very elongated barbules of the upper lip are supported by extensions of the intermaxillary bones, which increases the sphere of action and consequent utility of these organs of touch, by extending their influence beyond the range of the shorter cirri of the lower lip. Fishes furnished with these oral appendages are known by their habits to be ground-feeders ; and it may be mentioned, as affording additional proof of certain powers or qualities supposed to be possessed by such fishes, that Bloch says of this Silurus, it seldom leaves its hole except during storms. Another writer observes, that it lives long after being taken out of the water, and comes up to the surface on the approach of stormy weather.
Alwyne Wheeler (1969) in "The Fishes of the British Isles and North West Europe":
NAMES Fr. Silure glane; Du. Meerval; Ge. Wels, Waller; Da. Malle.
IDENTIFICATION Unmistakable on account of its broad head with six barbels, the longest, which extend past the pectoral fin base, on the upper jaw in front of the eye. There are a pair of shorter barbels on the lower jaw. The eye is small and the interorbital space wide. The mouth is wide. A small dorsal fin with three to five branched rays is sited midway between the pectoral and pelvic bases; an extremely long anal fin, with more than forty rays, is equal to about half the body length. It grows 16½ ft (5 m) and a weight of 660 lb (330 kg) in the U.S.S.R., on average to 60 in (152 cm) in Europe.
The colour varies with locality, but is usually olive green on the back and sides, creamy white ventrally. The back is sometimes sooty black and the sides have a bronze sheen.
D. 3-5; A. 84-92.
BIOLOGY A large solitary fish, it lives in still waters, usually marshes, lagoons, backwaters, lakes or deep reaches of large rivers. It appears to prefer a soft bottom, usually of mud, but sometimes of sand, and lives in holes in the river bed under overhangs of the banks, or under obstructions, such as sunken trees. It is most active at night. The wels tolerates brackish water in the Baltic and parts of the Black Sea. It makes certain limited migrations upriver for spawning, and downriver to recover from spawning, returning to the deep water in which in northern parts of its range it overwinters.
It is wholly carnivorous, whilst young eating a certain amount of bottom-living invertebrate life, but when larger eating fishes of all sorts, frogs, birds and small mammals.
The wels breeds from mid-May to mid-July in the marshy zones of lakes and on river flood plains. The pale yellow eggs are laid on mounds of dense leaf litter and are guarded by the male. They hatch in twenty-one to twenty-three days, the young looking rather like unpigmented tadpoles on hatching. They grow rapidly once feeding begins, reaching an average length of 12 in (30 cm) in their first year, about 16 in (40 cm) in their second, and reaching 33 in (100 cm) in length in their sixth or seventh year, although the rate of growth is very variable with habitat.
The wels forms the basis of a valuable fishery in eastern Europe and the U.S.S.R. The flesh of the young fish is well flavoured, and the largest specimens are processed, the skin yielding a type of leather. The eggs are said to be used as caviar, or to adulterate the true caviar. Wels are highly regarded as angling fishes; they are not delicate about baits and the ensuing tussle if a large one is hooked is a trial of both strength and skill.
Wels have been introduced in a number of private lakes in southern England, including those at Woburn Abbey, Bedfordshire and Claydon Lakes, Bucks, and near Leighton Buzzard, Beds. They have been introduced elsewhere, but do not always seem to have established a firm hold.
DISTRIBUTION
Eastwards to Asia.
