Man-Eating Wels Catfishes and Others

I had a request to put up some information about man-eating Wels catfish. However,  this blog posting on the subject was accumulating errors because of sluggish Bloggo service and had to be taken down. I apologise if that part inconvenienced anybody.
The primary recent source  thatsubject these days comes from the cable TV series River Monsters:

http://animal.discovery.com/fish/river-monsters/wels-catfish/

WELS CATFISH

Silurus glanis

Wels Catfish Photos | Monster Wels Catfish (video) | Wels Catfish Attacks (video) | Wels: Built to Kill (video)

Maximum Length: Up to 10 feet
Maximum Weight: Up to 330 pounds
Vicious and Voracious: The wels catfish is defined by a long, scaleless body; a broad, flat head; and an extremely wide mouth containing rows of small, sandpaper-like teeth — hundreds of them. It also has two sets of barbels (whisker-like organs) on the upper and lower jaw, which help the fish hunt its prey in the murky waters of large lakes and slow-flowing rivers across Europe. The wels catfish is an adept hunter, first using its pectoral fins to create a disorienting eddy and then taking advantage of its vast, vacuum-like mouth to suck prey in and swallow it whole.
Maneater or Misunderstood? Tales of man-eating wels catfish date back as far as the 15th century, but 2008 saw a spate of attacks in Lake Schlachtensee outside of Berlin. Many believe the attacker to be a 5-foot wels catfish. These fish have been caught in Russia with human remains in their stomachs, but most experts suspect the victims were already drowned before being swallowed. Still, the wels catfish can exhibit aggressive behavior during its mating season, making it plausible that this monster fish could be responsible for attacks against humans that venture into its territory.
Jeremy Wade's Tips for Catching Wels Catfish: "Because the water level has been raised by the dams, there are lots of sunken snags, so allowing the fish to run is not an option. But nobody's told the catfish that, and this one charged out into the current and almost pulled me over. It's then a long, drawn-out tug o' war, digging my heels into the slippery bank..."
For the full story, click on the fish icon over Europe on our River Monsters Map.

The wels catfish is an adept hunter, first using its pectoral fins to create a disorienting eddy and then taking advantage of its vast, vacuum-like mouth to suck prey in and swallow it whole

The wels catfish made headlines in 2008 after a spate of attacks in Lake Schlachtensee outside of Berlin.

http://en.wikipedia.org/wiki/Wels_catfish

Wels catfish

From Wikipedia, the free encyclopedia

The wels catfish ( /ˈwɛls/ or /ˈvɛls/;^[1] Silurus glanis), also called sheatfish, is a large catfish found in wide areas of central, southern, and eastern Europe, and near the Baltic and Caspian Seas. It is a scaleless fresh and brackish water fish recognizable by its broad, flat head and wide mouth. Wels catfish can live for at least thirty years and have very good hearing.
The wels catfish lives on annelid worms, gastropods, insects, crustaceans, and fish including other wels catfishes; the larger ones also eat frogs, mice, rats and aquatic birds such as ducks.

Habitat
The wels catfish lives in large, warm lakes and deep, slow-flowing rivers. It prefers to remain in sheltered locations such as holes in the riverbed, sunken trees, etc. It consumes its food in the open water or on the bottom, where it can be recognized by its large mouth. Wels catfish are kept in fish ponds as food fish.

Physical characteristics

Wels catfish's mouth contains lines of numerous small teeth, two long barbels on the upper jaw and four shorter barbels on the lower jaw. It has a long anal fin that extends to the caudal fin, and a small sharp dorsal fin positioned relatively far forward. It uses its sharp pectoral fins to capture prey. With these fins, it creates an eddy to disorient its victim, which it then simply engulfs in its enormous throat. It has very slippery green-brown skin. Its belly is pale yellow or white. Colour varies with environment. Clear water will give the fish a black coloration while muddy water will often tend to produce brownish specimens. Weight and length are not correlated linearly, and also depend on the season.
The female produces up to 30,000 eggs per kilogram of body weight. The male guards the nest until the brood hatches, which, depending on water temperature, can take from three to ten days. If the water level decreases too much or too fast the male has been observed to splash the eggs with the muscular tail in order to keep them wet.^{[citation needed]}

Size

Silurus glanis. Syr Darya River in Kazakhstan, Baikonur area.

With a possible total length up to 3 m (9.8 ft) and a maximum weight of over 150 kg (330 lb) it is the second largest freshwater fish in its region after the beluga sturgeon. However, such lengths are extremely rare and could not be proved during the last century, but there is a somewhat credible report from the 19th century of a wels catfish of this size. Brehms Tierleben cites Heckl's and Kner's old reports from Danube about specimens 3 m (9.8 ft) long and 200–250 kg (440–550 lb) heavy, and Vogt's 1894 report of a specimen caught in Lake Biel which was 2.2 m (7 ft 3 in) long and weighed 68 kg (150 lb).^[2] In 1856, K. T. Kessler^[3] wrote about specimens from Dniepr which were over 5 m (16 ft) long and weighed up to 400 kg (880 lb). "The largest authenticated wels, taken from the river Dnieper in the Ukraine in the southern U.S.S.R., measured over 16 ft (5 m) in length and weighed 675 lb (306 kg); elsewhere in Europe and in England, however, the wels seldom exceeds 5 ft (152 cm) in length and 25 lb (I 1 kg) in weight"

Most wels catfish are only about 1.3–1.6 m (4 ft 3 in–5 ft 3 in) long; fish longer than 2 m (6 ft 7 in) are normally extremely rare. At 1.5 m (4 ft 11 in) they can weigh 15–20 kilograms (33–44 lb) and at 2.2 m (7 ft 3 in) they can weigh 65 kilograms (140 lb).
Only under exceptionally good living circumstances can the wels catfish reach lengths of more than 2 m (6 ft 7 in), as with the record wels catfish of Kiebingen (near Rottenburg, Germany), which was 2.49 m (8 ft 2 in) long and weighed 89 kilograms (200 lb). This giant was surpassed by some even larger specimens from Poland, Ukraine, France, Spain (in the River Ebro), Italy (in the River Po and River Arno), and Greece, where this fish was released a few decades ago. Greek wels grow well thanks to the mild climate, lack of competition, and good food supply. The largest accurate weight was 144 kg (320 lb) for a 2.78 m (9 ft 1 in) long specimen from the Po Delta in Italy.^[4] Other reports of larger wels (around 5 m (16 ft) or more) are unlikely and are often regarded as typical big fish stories or in some cases misidentifications of the now rare sturgeon.
Exceptionally large specimens are rumored to attack humans in rare instances, a claim investigated by extreme angler Jeremy Wade in an episode of the Animal Planet television series River Monsters. A report in the Austrian newspaper Der Standard on August 5, 2009, mentions a wels catfish dragging a fisherman near Győr, Hungary, under water by his right leg after the man attempted to grab the fish in a hold. The man barely escaped with his life from the fish, which must have weighed over 100 kg (220 lb), according to the fisherman.^[5]

Ecology

There are concerns about the ecological impact of introducing the wels catfish to non-native regions. These concerns take into account the situation in Lake Victoria in Africa, where Nile perch (available in stores as Lake Victoria perch) were introduced and rapidly caused the extinction of numerous indigenous species. This severely impacted the entire lake, destroying much of the original ecosystem. The introduction of foreign species is almost always a burden on the affected ecosystem. Following the introduction of Wels catfish are fishes whose number is in clear and rapid decline. Since its introduction in the reservoir Mequinenza in 1974 - has spread to other parts of the Ebro basin over Ebro and its tributaries, especially river Segre. Some endemics species of iberian barbels, genus Barbus in the Cyprinidae, having once been abundant especially in the Ebro river, competition and predation by wels catfish has caused its complete disappearance in the middle channel Ebro around 1990. The ecology of the river also, has now a major development in the amount of aquatic vegetation, seaweed and algae. Barbel species from mountain stream tributary of the Ebro that wels catfish has not colonized, were not affected.

As a food fish

Only the flesh of young Silurus glanis specimens is valued as food. It is palatable when the catfish weighs less than 15 kg (33 lb). Larger than this size, the fish is highly fatty and not recommended for consumption. The eggs are poisonous and should not be consumed.

Related species

• Aristotle's catfish (Silurus aristotelis) from Greece, the only other native European catfish species beside Silurus glanis.
• Amur catfish (Silurus asotus), introduced to European rivers
• Brown bullhead (Ameiurus nebulosus)
• Mekong giant catfish on the lower reaches of the Mekong

References

1. ^ OED
2. ^ Brehm, Alfred; Brehms Tierleben II - Fish, Amphibians, Reptiles 1
3. ^ Mareš, Jaroslav; Legendární příšery a skutečná zvířata, Prague, 1993
4. ^ Wood, The Guinness Book of Animal Facts and Feats, Sterling Pub Co Inc (1983), ISBN 978-0851122359
5. ^ Der Standard, 2009-08-05. Waller-Wrestling im ungarischen Fischerteich. Retrieved 2009-08-06. (German)

• World Conservation Monitoring Centre (1996). Silurus glanis. 2006. IUCN Red List of Threatened Species. IUCN 2006. www.iucnredlist.org. Retrieved on 09 May 2006.
• Froese, Rainer, and Daniel Pauly, eds. (2006). "Silurus glanis" in FishBase. March 2006 version.
• "Silurus glanis". Integrated Taxonomic Information System. http://www.itis.gov/servlet/SingleRpt/SingleRpt?search_topic=TSN&search_value=164068. Retrieved 19 March 2006.

External links

FishBase species summary

YouTube video of a giant Wels Catfish being caught

This article includes information translated out of the German and French Wikipedias.

--So basically the answer seems to be, when the wels catfish gets big enough and there are human beings present in the water, the catfish is as likely to go after them as any other prey. Catfishes are very indiscriminate feeders. The thing is, they habve to be allowed to get that big, and few of them get that big in Europe any more (larger ones may be commoner in Central Asia these days). Lucas writes wondering if introduced wels catfishres might be mistaken for giant eels: and my answer is that my experience has been that usually witnesses make the distinction. There are some very eel-like catfishes, byt the wels has a fat body that is vaguely tadpole-shaped overall. ntroduced wels might make perfectly acceptable water monsters, my feeling is that ordinarily witnesses make the distintion between them and the eels.
Best Wishes, Dale D.