---
title: "What the sources say about the Wels Catfish | AnimalTracks.wiki"
description: "55 claims from the Wels Catfish profile, each beside the words of the source that backs it."
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# What the sources say about the Wels Catfish (*Silurus glanis*)

> 55 claims from the Wels Catfish profile, each beside the words of the source that backs it. A "..." marks a cut in a quote and [brackets] an insertion.

Profile: [Wels Catfish](https://animaltracks.wiki/animals/wels-catfish/)

## Silurus glanis Linnaeus, 1758. FishBase.

https://www.fishbase.se/summary/Silurus-glanis.html

| The page says | The source says |
| :--- | :--- |
| Recorded maxima of 2.73 meters and 130 kilograms | The recorded maxima with evidence are 2.73 m and 130 kg |
| For a long time, the wels catfish's recorded maximum stood at five meters and 306 kilograms | The maximum length of the species has been recorded as 5 m for a long time and the maximum weight as 306 kg |
| FishBase says misidentifications and problems with measurement units produced those numbers | misidentifications and problems of measurment units have led to these numbers (note: source typo 'measurment') |
| gives 2.73 meters and 130 kilograms as the maxima backed by evidence | The recorded maxima with evidence are 2.73 m and 130 kg |
| FishBase puts the maxima backed by evidence at 2.73 meters and 130 kilograms | The recorded maxima with evidence are 2.73 m and 130 kg |
| For a long time the species' recorded maximum stood at 5 meters and 306 kilograms | The maximum length of the species has been recorded as 5 m for a long time and the maximum weight as 306 kg |
| FishBase says misidentifications and problems with measurement units led to those figures | misidentifications and problems of measurment units have led to these numbers |

## Silurus glanis (Danube catfish). Animal Diversity Web, University of Michigan.

https://animaldiversity.org/accounts/Silurus_glanis/

| The page says | The source says |
| :--- | :--- |
| Large rivers, lakes, and deep water near dams, native to eastern Europe and Asia and introduced elsewhere in Europe, sometimes entering brackish water in the Baltic and Black Seas | native to eastern Europe and Asia. It has been introduced to several other areas including Germany, France, Spain, England, Greece, Turkey and the Netherlands ... 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 |
| Fish, eels, crayfish, frogs, snakes, voles, rats, coypu, ducks | At adult sizes they will also prey on ducks, voles, crayfish, fish, eels, frogs, rats, coypu, and snakes (note: pigeons: see the freshwater-2012 claims) |
| Most individuals reach 1.3 to 1.6 meters and an average of 45 kilograms | Most individuals reach sizes between 1.3 and 1.6 meters. Silurus glanis reach an average of 45 kg |
| The scaleless body is elongated, with a laterally flattened tail, and the fish prefers still water, usually over a soft bottom such as mud | The elongated, scaleless body has a strong upper body and a laterally flattened tail ... prefers still waters, usually with a soft bottom like mud |
| The wels catfish is most active at night | These fish are most active at night |
| It senses chemical cues with its barbels and olfactory buds, thought to be extraordinarily sensitive, and a lateral line system helps it detect water movement | 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. |
| The catfish takes prey in with the suction of a suddenly opened mouth, grips it with hundreds of soft, inward-sloping teeth on each jaw, and crushes it on two plates in front of the throat before swallowing | 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. |
| Adults prey on fish, crayfish, frogs, voles, rats, and ducks | At adult sizes they will also prey on ducks, voles, crayfish, fish, eels, frogs, rats, coypu, and snakes. |

## Cucherousset et al. (2012). “Freshwater Killer Whales”: Beaching Behavior of an Alien Fish to Hunt Land Birds. PLoS ONE.

https://doi.org/10.1371/journal.pone.0050840

| The page says | The source says |
| :--- | :--- |
| Europe's largest freshwater fish | European catfish Silurus glanis L., the world's third largest and Europe's largest freshwater fish (note: tagline; the 2012 paper's own words) |
| on one French river, a hunter that beaches itself | Fifty-four beaching behaviors with partial and mostly complete stranding were observed and filmed (note: beaching = the paper's 'partial and mostly complete stranding'; the river is the Tarn (see body claims)) |
| to grab pigeons off a gravel island | a gravel island where pigeons ( Columbia livia Gmelin) regroup for drinking and cleaning |
| on one French river, pigeons | to capture birds on land (i.e. pigeons, Columbia livia ) (note: the Tarn River study) |
| A 2012 study calls Silurus glanis the world's third largest and Europe's largest freshwater fish | European catfish Silurus glanis L., the world's third largest and Europe's largest freshwater fish |
| Wels catfish were introduced to the Tarn River in southwestern France in 1983 | We conducted the present study in the Tarn River (Southwestern France) within the historical city center of Albi, a UNESCO World Heritage Centre. European catfish were introduced in the Tarn River in 1983 |
| In Albi, scientists filmed them lunging out of the water to seize pigeons on a gravel island | within the historical city center of Albi, a UNESCO World Heritage Centre. European catfish were introduced in the Tarn River in 1983 and have since established self-sustained populations [12] . Behavioral monitoring was performed from a bridge above a gravel island where pigeons ( Columbia livia Gmelin) regroup for drinking and cleaning |
| a behavior not reported in the species' native range | this extreme behavior has not been reported in the native range of the species |
| Over 24 surveys they recorded 54 beaching attempts, and 15 of them, or 28 percent, caught a bird | During the 24 surveys conducted in an urbanized stretch of the Tarn River (France) ... Fifty-four beaching behaviors with partial and mostly complete stranding were observed and filmed (Movie S1), among which 28% (n = 15) were successful, i.e. the land birds were captured on land (note: 54 is 'Fifty-four' in the source) |
| The attacks were systematically triggered by active pigeons; motionless pigeons were never attacked, even very close to a catfish | The attacks were systematically triggered by active pigeons. Indeed, motionless pigeons, even very closed to the European catfish, were never attacked. |
| As the fish approached, they raised their upper jaw barbels, which the researchers say suggests they were detecting water vibrations rather than watching the bird | European catfish were observed to exhibit erected upper jaw barbels on the upper jaw when they approach pigeons, suggesting that water vibrations, rather than visual cues, were used to detect and attack the prey |
| Each lunge lasted from less than a second to no more than four seconds, and in about 40 percent of observations the catfish had more than half its body out of the water | In approximately 40% of all observations, European catfish had more than half of their body outside of the water. The beaching behavior was quick, lasting from less than one second to no more than 4 seconds. |
| and on the Tarn, pigeons | to capture birds on land (i.e. pigeons, Columbia livia ) |
| Europe's Biggest Freshwater Fish | European catfish Silurus glanis L., the world's third largest and Europe's largest freshwater fish (note: heading) |
| On the Tarn River in southwestern France, where the species was introduced, catfish strand themselves on a gravel island where pigeons gather to drink and clean | We conducted the present study in the Tarn River (Southwestern France) ... European catfish were introduced in the Tarn River in 1983 ... a gravel island where pigeons ( Columbia livia Gmelin) regroup for drinking and cleaning |
| A strike takes no more than 4 seconds, and a caught bird is returned to the river and swallowed | returned to the river and swallowed ... The beaching behavior was quick, lasting from less than one second to no more than 4 seconds |
| Motionless pigeons were never attacked | motionless pigeons, even very closed to the European catfish, were never attacked |
| The fish erect their upper jaw barbels on the approach, which the study reads as a sign they detect the prey through water vibrations rather than sight | European catfish were observed to exhibit erected upper jaw barbels on the upper jaw when they approach pigeons, suggesting that water vibrations, rather than visual cues, were used to detect and attack the prey |

## Pohlmann, Grasso & Breithaupt (2001). Tracking wakes: The nocturnal predatory strategy of piscivorous catfish. Proceedings of the National Academy of Sciences.

https://doi.org/10.1073/pnas.121026298

| The page says | The source says |
| :--- | :--- |
| the ability to track a prey fish's wake with no visible light | locate a piscine prey (guppy, Poecilia reticulata) by accurately tracking its three-dimensional swim path before an attack in the absence of visible light |
| In a 2001 lab study, catfish located a guppy with no visible light by tracking its three-dimensional swim path, following wakes up to 10 seconds old over distances up to 55 guppy body lengths | nocturnal European catfish (Silurus glanis) locate a piscine prey (guppy, Poecilia reticulata) by accurately tracking its three-dimensional swim path before an attack in the absence of visible light. Wakes that were up to 10 s old were followed over distances up to 55 prey-body lengths in our setup (note: 'in our setup' is carried by 'lab study') |
| Wakes drew attacks from the rear, which the authors say may be harder for prey to detect | wakes elicit rear attacks, which may be more difficult to detect by prey |
| Swimming fish leave wakes holding hydrodynamic and chemical traces | Swimming fish leave wakes containing hydrodynamic and chemical traces. |
| In a lab experiment with no visible light, catfish located guppies by tracking their three-dimensional swim path, following wakes up to 10 seconds old across as much as 55 guppy body lengths | locate a piscine prey (guppy, Poecilia reticulata) by accurately tracking its three-dimensional swim path before an attack in the absence of visible light. Wakes that were up to 10 s old were followed over distances up to 55 prey-body lengths in our setup |
| Following a wake brought them in from behind, and the authors suggest rear attacks may be harder for prey to notice | wakes elicit rear attacks, which may be more difficult to detect by prey |

## Bergström et al. (2022). Exceptional longevity in northern peripheral populations of Wels catfish (Silurus glanis). Scientific Reports.

https://doi.org/10.1038/s41598-022-12165-w

| The page says | The source says |
| :--- | :--- |
| In the species' core range, studies reviewed in 2022 put maturity at 4 to 7 years old and 70 to 100 centimeters long | Previous studies have shown that catfish in these areas can reach a length of 70–130 cm within 5–7 years and become mature at 70–100 cm of length ... after becoming mature (at an age of 4–7 years (note: replaces ADW's single-study 3/4 years and FishBase's 86-108 cm, which disagree with each other; the 2022 review is the newer source) |
| In the core range, estimates suggest catfish very rarely live past 20 years | Estimates of longevity also suggest that catfish in these areas very rarely become older than 20 years (note: replaces ADW's older '20 to 30 years' expected wild lifespan, which the 2022 paper contradicts) |
| Three native populations in southern Sweden are postglacial remnants, established 9,500 to 8,000 years ago | three postglacial remnant populations (present in Lake Möckeln, River Emån and Lake Båven) in southern Sweden ... The northern peripheral populations of catfish were established in Sweden during warmer post glacial ages, 9500 to 8000 years ago |
| they grow very slowly by comparison | revealed very slow growth rates compared to catfish within the core distribution area |
| fish of about 175 centimeters are estimated to add around 2 centimeters a year | individuals at a length of about 175 cm estimated to grow around 2 cm/year |
| A 15-year tagging study in two of those systems | we conducted an extensive mark-recapture study across 15 years. Using a combination of fyke-nets and long-lining, we captured and tagged 1183 individuals ranging from 7 to 209 cm in two (out of three) of the Swedish systems inhabited by catfish |
| recaptured a 195-centimeter catfish estimated to be 70 years old | the largest recaptured individual (length 195 cm) was estimated to be 70 (95% CI 50–112) years old |
| about twice the age of the oldest previously reported, a 33-year-old from Russia's Volga River | The oldest previously reported catfish found was from the river Volga in Russia was 33 years and 266 cm long 22 , which is about half the estimated age of our largest recaptured individual (note: the paper's 'about half', inverted) |
| In 2022 the authors urged Swedish authorities to keep the closure of catfish fisheries that began in 1994 | we would like to strongly recommend authorities to maintain the closure of catfish fisheries in Sweden initiated in 1994 (note: dated to the paper; no claim that it is still closed) |
| The Slow Giants of Sweden | Despite a large demand from the recreational fishery to target these giant fish in Sweden once again (note: heading; 'slow' is the paper's 'very slow growth rates') |
| In the core range, estimates suggest wels catfish very rarely pass 20 years | Estimates of longevity also suggest that catfish in these areas very rarely become older than 20 years |
| In southern Sweden, a 15-year mark-recapture study | we conducted an extensive mark-recapture study across 15 years |
| estimated a 150-centimeter fish to be around 40 years old | The fitted von Bertalanffy growth curve predicted a 150 cm catfish to be around 40 years old |
| its largest recaptured fish, 195 centimeters long, to be 70, with a 95 percent confidence interval of 50 to 112 years | the largest recaptured individual (length 195 cm) was estimated to be 70 (95% CI 50–112) years old |

## Cunico & Vitule (2014). First records of the European catfish, Silurus glanis Linnaeus, 1758 in the Americas (Brazil). BioInvasions Records.

https://doi.org/10.3391/bir.2014.3.2.10

| The page says | The source says |
| :--- | :--- |
| Far outside its native range, the species has even turned up in Brazil, where one was caught in a river in 2006 and another found dead in a pond beside a river in 2010 | Although it originally inhabited rivers of Eastern Europe and Western Asia ... In August 2006, in the State of Santa Catarina, Southern Brazil ... the capture of a huge catfish by an amateur fisherman in the Itajaí-Açu River, which was identified as S. glanis . In March, 2010, the Laboratory of Ecology, Ichthyology and Fisheries (LEPI) of the Federal University of Paraná received another individual of S. glanis that had died in a small pond next to the Piquiri River |

## Freyhof (2022). Silurus glanis. The IUCN Red List of Threatened Species 2024: e.T40713A221242562.

https://doi.org/10.2305/iucn.uk.2024-2.rlts.t40713a221242562.en

| The page says | The source says |
| :--- | :--- |
| Its 2022 IUCN Red List assessment lists the species as Least Concern | IUCN Red List category: Least Concern (LC). (note: reference is the 2024 assessment (DOI iucn.uk.2024-2)) |