This albino young seems to smile affable. (Zuchtmöglichkeiten des Welses in Teichen in Polen.) S. glanis has a broad omnivorous diet, including invertebrates and vertebrates such as small rodents. Some of the environmental impacts of the species (see the Environmental Impact section) might have economic effects. [English title not available]. However, Martino et al. Technical Proceedings of the Conference on Aquaculture in the Third Millennium, Bangkok, Thailand, February 2000. There are reports of escapes from aquaculture and recreational fisheries, for example in France where it escaped into the River Doubs in about 1890 (Valadou, 2007). However, many aspects of behaviour are still unknown, and Valadou (2007) suggests that virtually all aspects of the biology of introduced S. glanis require study. Investigating the catch returns and growth rate of Wels catfish (Siluris glanis), using mark-recapture. The colour is dark grey on the back and goes down on the sides with a moire where clear and dark colours mix irregularly, to end in an opaque white belly. Évolution de son aire de répartition et prédiction de son extension ([English title not available]). Some example maps demonstrate the extent of introductions. Native populations extend from Germany to Eastern Europe including Poland and southern Sweden, and also from northern Iran and southern Turkey to the Baltic states and Russia, and to the Aral sea of Kazakhstan and Uzbekistan (Copp et al., 2009). Two small eyes, with circular pupil, stand out laterally just over the oral margins. Elvira B, 2001. Consent is usually not granted for open waters, although enclosed waters are permitted (Britton and Pegg, 2007; Copp et al., 2009). Polish Journal of Natural Sciences, 23(4), 850-857. http://versita.com/science/agriculture/pjns/ doi: 10.2478/v10020-008-0008-0, Kim LeeOh, Lee SangMin, 2005. datasets have provided data to the NBN Atlas for this species.. Browse the list of datasets and find organisations you can join if you are interested in participating in a survey for species like Silurus glanis … Life span is normally 15-30 years, with a maximum recorded age of 80 years (Kottelat and Freyhof, 2007). August 2011. This species requires temperatures of 25-28ºC for optimal growth, food assimilation and breeding (Copp et al., 2009). A review of the environmental biology of European catfish Silurus glanis in its native and introduced ranges. Mareš, J., Jirásek, J., Ondra, R., 1996. V.V., 1983). - Contenimento della presenza di Silurus glanis nelle acque dell’Adda ricomprese nel territorio del Parco Adda Nord e, nel comtempo, contenimento di altre specie ittiche alloctone dannose per l’equilibrio delle specie autoctone (come il gardon, il rodeo amaro, il carassio). Rehabilitación de dique salinero como territorio de reproducción de los flamencos. According to Linhart et al. of coldest month > 0°C and < 18°C, mean warmest month > 10°C, Cf - Warm temperate climate, wet all year, Warm average temp. 2009; Syväranta et al. Maximum length is 500 cm (male), but common lengths are 300 cm, and weight 306 kg. In April 2012, accidental flooding from licensed lakes containing wels catfish into flood valleys of the River Colne and Chelmer in East Anglia were being investigated. (2003) reported that more than 50% of successful invasive fish species introduced into the UK exhibit parental care, where fish actively protect and guard their eggs or larvae and defend territories. When several references are cited, they may give conflicting information on the status. Further details may be available for individual references in the Distribution Table Details section which can be selected by going to Generate Report. The wels catfish S. glanis is part of the family Siluridae, a group of freshwater fish native to Europe, Asia and Africa. Ecological Applications, 16(6):2313-2324. http://www.esajournals.org/perlserv/?request=get-abstract&doi=10.1890%2F1051-0761%282006%29016%5B2313%3AHDAIRO%5D2.0.CO%3B2, Copp GH, Britton JR, Cucherousset J, García-Berthou E, Kirk R, Peeler E, Stakenas S, 2009. Aquatic Invasions, 2:113-116, Copp GH, Vilizzi L, Gozlan RE, 2010. Molecular Ecology, 8(11):1964-1966, Linhart O, Stech L, Svarc J, Rodina M, Audebert JP, Grecu J, Billard R, 2002. S. glanis is listed as Least Concern (LC) in the IUCN Red List of Threatened Species (http://www.iucnredlist.org/). The European catfish (Silurus glanis) can reach the 80 years with record size of 5 m and 300 kg. 2009). Public Domain - Released by Yuriy75/via wikipedia - CC0. Risk of establishment increases in warmer climates such as the Mediterranean as rapid growth and breeding are enhanced by warmer temperatures of 25-28ºC in contrast to likelihood of more sporadic establishment in Northern climates. Aquatic Living Resources, 15:139-144, Marcel J, 1980. A “do nothing” approach is advocated in low risk situations, whereas removal or containment are considered options in higher risk situations. Native to eastern Europe and western Asia it is now established in several countries to the west and south of its native range. Maximum reported age is 80 yrs (Kottelat and Freyhof, 2007), although life span is commonly 15-30 yrs. Bonjour à tous ! SiluroMania si occupa inoltre della salvaguardia del silurus glanis, diventato un vero e proprio capro espiatorio per i crimini compiuti dall'uomo nell'ambiente. The name of the genus comes from the Latin “silurus” that means torpedo indicating the big freshwater fish. However the species still accounts for only a small percentage of European freshwater aquaculture. S. glanis exhibits cannibalism when food resources are scarce, or (Copp et al., 2009) in angling waters when there is variation in size among members of the species. The newborns will remain in the nest till when they have not competely absorbes the yolk sac and will reach the sexual maturity in 2-3 years. GardaPost Gen 11, 2020. 2011; Syväranta et al. Of presumable Danubian origin, this fish has diffused in almost all European rivers and lakes, often introduced by the man, as well as in the Caspian and Lake Aral basins, colonizing also the Anatolia, the southern part of the Baltic countries, and even areas of Great Britain and of Spain. [Cefas Science Technical Report No. On the outer sides of the chin two more couples of barbels complete the range of the sensors. by Cowx, I. G.]. Assessing the effects of climate change on aquatic invasive species. Again from the Greek word glanis, which is the name of the fish: Species Information; Size: 5000mm or 196.9" … Concerns about accidental unregulated spread (flooding enabling spread from angling waters to watercourses and rivers) and intentional unregulated releases (for angling) imply that S. glanis introductions need to be investigated, particularly as angling and dispersal are cited as the main introduction routes for introduced fish in the UK ( Copp et al. Establishment success in France has been restricted by cold winter temperatures of <10ºC (David, 2006). A seguito delle ormai numerose catture di esemplari di “silurus glanis” (siluro d’Europa) nelle acque del nostro lago di Garda avvenute negli ultimi periodi, l’ Unione Pescatori Sportivi del Garda (UPSdG) domenica 12 gennaio organizza un monitoraggio mirato al censimento di questa infestante e pericolosa specie alloctona. Aquatic Conservation: Marine and Freshwater Ecosystems, 20(3):269-273. http://www3.interscience.wiley.com/cgi-bin/fulltext/123297656/PDFSTART, Crivelli AJ, 1995. 2007; Carol et al. Silurus glanis (wels catfish); adult, in the open water of a former surface mine near Leipzig, Germany. Gillnet selectivity and its relationship with body shape for 8 freshwater species. Simoens et al. The skin is smooth, has no scales and is covered by slippery mucus. Gli impatti economici sono più probabili nei laghi prealpini (ove si esercita maggiormente la pesca di professione), mentre gli ... www.naturachevale.it . Within these habitats the fish prefer benthic woody tree root habitats and stony crevices for refuge and cover. One or more of the features that are needed to show you the maps functionality are not available in the web browser that you are using. siluro, con una buona conoscenza del territorio. The fore part is robust and almost flattened on the head. Males have running milt 30-40 days before spawning and produce sperm for relatively long periods, with a gradual, extended duration of spermatozoa discharge (Shikhshabekov, 1978). Eggs are protected by mucous and stickiness. Larval development and growth of the European wels (Silurus glanis) under experimental conditions fed natural and pelleted diets. Gozlan et al. Colossal aggregations of giant alien freshwater fish as a potential biogeochemical hotspot. Combattimento mozzafiato in deriva sul fiume Po. Its greater production in Bulgaria has been suggested (Hadjinikolova et al., 2010). Silurus glanis (Linnaeus, 1758) Appearance. Hendry, A. P., Wenburg, J. K., Bentzen, P., Volk, E. C., Quinn, T. P., 2000. There are 18 Silurus species, of which two are native to Europe: wels catfish and Aristotle's catfish (S. aristotelis). The European catfish or Wels catfish ( Silurus glanis Linnaeus 1758) is a freshwater fish belonging to the class of the Actinopterygii, ray-finned fishes, to the order of the Siluriformes, and to the family of the Siluridae, that has no rigid rays in the dorsal, has no adipose fin and has some small ventral fins (at … Evaluation of selected feeds differing in dietary lipids levels in feeding juveniles of wels catfish, Silurus glanis L. Acta Ichthyologica et Piscatoria, 38(2), 91-96. doi: 10.3750/AIP2008.38.2.02, Muscalu, R., Muscalu, C., Nagy, M., Bura, M., Szelei, Z. T., 2010. [ISBN 90-71625-03-6], Hilge, V, 1984. GISD/IASPMR: Invasive Alien Species Pathway Management Resource and DAISIE European Invasive Alien Species Gateway. Roczniki Nauk Rolniczych, Seria H, Rybactwo, 102(1):131-167. Upstream spring migration in April for spawning requires temperatures of 8-10ºC and initiation of spawning occurs at 18-22ºC. Preferred habitats are slow flowing lowland rivers, backwaters, shallow channels in floodplains and weed covered lakes. Aquacultura Hungarica, 4: 135-144. 02015 1144 Geräucherte Spezialitäten aus Schlesien.JPG 2,159 × 2,989; 2.28 MB Journal of Applied Icthyology, 1:27-31, Jamróz, M., Kucharczyk, D., Kujawa, R., Mamcarz, A., 2008. Habitat use follows a daily pattern, and incorporates territorial behaviour. Of possible Danubian origin, the catfish has diffused, thanks to the man, in almost all European rivers and lakes with serious damage to the local species. (Le silure glane n'est pas un monster.) http://www.fishbase.org, Gozlan RE, Flower CJ, Pinder AC, 2003. Lowestoft, UK: Cefas, 32 pp. S. glanis was introduced to Netherlands from Hungary for this purpose. It was first introduced to England in 1880, into enclosed recreational lakes of a private Bedfordshire manor estate at Woburn Abbey, for fishing. Aquaculture: a biotechnology in progress: volume 1. International Conference: Aquaculture Europe, Amsterdam, Netherlands, 2-5 Jun 1987. Preliminary telemetry data on the patterns and habitat use of European catfish (Silurus glanis) in a reservoir of the River Ebro, Spain. A potential beneficial ecological effect is that S. glanis can predate on signal crayfish (Pacifastacus leniusculus), which is an invasive species in Europe that is adversely effecting native crayfish populations (Carol et al., 2009; Copp et al., 2009). Our inland waters have very impoverished and this dearth by sure is not favouring important dimensions. Turk Veterinerlik ve Hayvancilik Dergisi, 28:613-622, Alp, A., Kara, C., Üçkardes, F., Carol, J., García-Berthou, E., 2011. Detailed coverage of invasive species threatening livelihoods and the environment worldwide. 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. 2008; Muscalu et al. In the UK, wels catfish, because they are non-native, require an ILFA (Introduction of Live Fish Act) license for introduction as part of regulatory legislation control and enforcement. Pesci siluro nel Garda, l’allarme dei pescatori . In their native range, catfish are under threat from anthropogenic changes including river modifications resulting in the loss of shallow spawning sites (Hamackova et al., 1997; Copp et al., 2005; Copp et al., 2007). Triantafyllidis et al. Spawning is nocturnal. Current Frontiers in Cryopreservation, 13:254-267, Boujard T, 1995. Foraging is an important aspect of growth and Muscalu et al. Reviewers' names are available on request. The feeding selectivity of wels (Silurus glanis L.) in Lake Goreckie. 2001) with some limited but renewed awareness among fish farmers in France and Germany (Linhart et al. pond cultivation. Silurus glanis, conosciuto volgarmente come siluro o siluro d'Europa o anche pesce siluro, è un pesce d'acqua dolce europeo, appartenente alla famiglia dei Siluridae e all'ordine Siluriformes. It fathoms every fissure and hideout among the weeds with its long upper barbels that, like blind sticks, swings for exploring the whereabouts. Genetic structure and phylogeography of European catfish (Silurus glanis) populations. CABI is a registered EU trademark. The pale abdomen is the surprises zone: rarely deflated, it often shows protrusions that speak volumes about the appetite of the fish. The catfishes spend the day in impenetrable hideouts and get out hunting by night; amphibians and young fishes but then also small mammals and aquatic birds © G. Mazza. ... silurus glanis. Development of technological regimes of European catfish (Silurus glanis L.) growing in the ponds of Belarus. Pond culture of fish in Romania. By closing strongly the jaws, it gradually chokes the victims closing their gills while, simultaneously, rotates them in way that the spines are not opposite to the way leading them to the stomach. Following spawning, S. glanis exhibits a guarders and nesters reproductive strategy with the male protecting the cluster of eggs laid by the female in his nest excavated amongst the substratum and made from plant material. 2003; Carol et al. Foto AdobeStock | Fyle. They can be identified by 6 barbels, 2 long ones on each side of the mouth and 4 shorter ones from the lower jaw. Please consider upgrading your browser to the latest version or installing a new browser. Use of frozen zooplankton in the intense rearing of European catfish (Silurus glanis L.) larvae. It appears to establish relatively easily after introduction, especially in warmer climates such as around the Mediterranean (Crivelli, 1995). The introduction of S. glanis in angling clubs is likely to increase revenue to local communities and generate business. Fish and Fisheries. Moreover, the flesh is good even if, due to the pollution, before eating it would be better to contact the veterinary authorities. Acta Scientiarum Polonorum - Piscaria, 2(1), 183-194. 60:21-36. Under them an ample mouth with fleshy lips and strong jaws with tiny teeth, who do not forgive those being aspirated. Siluro mostro in vertical con fireball. FishBase. Since 1975, it has been farmed for its meat in pond cultures in Italy and former Yugoslavia, and also in its native range in Hungary, Poland, Slovakia and Lithuania (and also Belarus -- Dokuchayeva, 2011) where it is considered an expensive meat delicacy. 2012). The Import of Live Fish Act 1980 (ILFA) is a legislative framework to control importation of non-native fishes, and the Fish Invasive Screening Kit (FISK) is a scoring system to assess the range of risk of non-native fish introduction ranging from potential pest to harmless, based on the evaluation of life history traits of non-native fish species, e.g. Kafkas Üniversitesi Veteriner Fakültesi Dergisi, 18(5), 775-780. http://vetdergi.kafkas.edu.tr/extdocs/2012_5/775-780.pdf, Clavero M, García-Berthou E, 2006. [English title not available]. Acta Ichthyologica et Piscatoria, 27(1), 41-50. They can also use holes or burrows of clay and muddy bottom substrate of lakes and ponds and are often hidden among dense macrophyte cover. The European catfish (Silurus glanis) can reach the 80 years with record size of 5 m and 300 kg. Growth is an integrating variable of fish physiology and behaviour, and reduced growth can result from a variety of factors: food abundance, fish age, social hierarchy, change in water temperature, habitat and increased energy expenditures (Zaikov et al. The tiny dorsal fin on its upper body, rounded caudal fin and strong upper body assist the swimming motion. Testicles in males are a pair of glands in the dorsal main cavity, white when mature, but pink when developing (Shikhshabekov, 1978). S. glanis is a popular fish among anglers because of its large size and relatively frequent capture. Fisheries and Aquaculture Department. It has been introduced to several other areas including Germany, France, Spain, England, Greece, Turkey and the Netherlands. Due to the variable regulations around (de)registration of pesticides, your national list of registered pesticides or relevant authority should be consulted to determine which products are legally allowed for use in your country when considering chemical control. [Unpublished report], Ricciardi A, Steiner WWM, Mack RN, Simberloff D, 2000. Considerations regarding the rearing of European catfish, Silurus glanis L. in a flow-through production aquaculture system. This species is in the lower region of the high risk score category of potential pests in ENSAR (European non-native species aquaculture risk assessment) to evaluate the risk of introduction, establishment, dispersal and impacts, although this may be variable according to context (Copp et al., 2009). A model of isolation by distance seems more probable and a hypothesis of recent dispersion from only one glacial refugium around the Ponto-Caspian region is proposed. However, consideration must be given to the economic costs that are likely to arise from management control policies with the removal of S. glanis from unlicensed waters; monitoring, removal costs and challenges in recapturing demersal species. Fisheries for non-native species in England: angling or the environment? Introduction of S. glanis for aquaculture and enhancement of sport angling is common. 2008). Testing the Alms Welsfutter diet on sheath fish (Silurus glanis) culture in silos. Il siluro (Silurus glanis Linnaeus, 1758) nelle acque del Lago di Massaciuccoli: un rischio per la biodiversità ... tipico delle aree umide del territorio nazionale (A.A. This fish has boneless white flesh that is low in fat and highly palatable. Contenimento del siluro (Silurus glanis) nel fiume Adda Nel corso del 2019 dando seguito alle disposizioni di Regione Lombardia (DGR n.1965 del 22/7/21019), il Parco ha proceduto alla realizzazione di un progetto di contenimento di esemplari della specie Silurus glanisnel tratto del corso del fiume Adda ricadente nel territorio del Parco. Journal of Biological Research, 15:25-35. http://www.jbr.gr/papers20111/03-Vittas-et-al.pdf, Wisniewolski W, 1989. > 10°C, Cold average temp. The wels catfish S. glanis is part of the family Siluridae, a group of freshwater fish native to Europe, Asia and Africa. Froese R, Pauly D, 2012. The different routes of introduction are pertinent regarding release of non-native fish, as some routes such as angling have a greater risk of unregulated transfer activities from fishermen in unsupervised lakes. → For general information about fishes please click here. The breed effect on productivity and meat nutrient compsition of fish. There are 100 species from 12 genera in the family. Fisheries Management and Ecology, 11:203-212, Hilge V, 1989. The European catﬁ sh (Silurus glanis, Linnaeus, 1758) in the waters of Massaciuccoli Lakes: a risk to biodiversity ... tipico delle aree umide del territorio nazionale (A.A. Biological Invasions, 12(1), 125-131. http://www.springerlink.com/content/l743q272m5266518/?p=b8eb71c07ab345d1a474d1e523242c58&pi=11 doi: 10.1007/s10530-009-9436-1, Carol J, Benejam L, Benito J, Garcia-Berthou E, 2009. S. glanis is in the lower range of the high risk score of FISK, although these scores are variable and likely to change in relation to the context of environmental factors affecting risk (Copp et al., 2005). > 0°C, dry winters), CR (IUCN red list: Critically endangered), Competition - monopolizing resources; Predation, CR (IUCN red list: Critically endangered); USA ESA listing as endangered species, DIAS, Database on Introductions of Aquatic Species. Freshwater Biology, 55(5):1130-1141. http://www3.interscience.wiley.com/cgi-bin/fulltext/123349915/HTMLSTART, Britton JR, Pegg J, 2007. Archives of Polish Fisheries, 11:141-147, David JA, 2006. (2002), S. glanis has been farmed historically in Austria, Bulgaria, Croatia, Germany, France, Hungary, Greece, Macedonia, Poland, the Czech Republic and Romania. SILURUS GLANIS ASSOCIATION has 2,760 members. (2002), S. glanis has been farmed historically in Austria, Bulgaria, Croatia, Germany, France, Hungary, Greece, Macedonia, Poland, the Czech Republic and Romania. Silurus glanis, conosciuto volgarmente come siluro o siluro d'Europa o anche pesce siluro, è un pesce d' acqua dolce europeo, appartenente alla famiglia dei Siluridae . Silurus glanis - Wikipedi . Consumption of food sources is related to gape size with the larger catfish >120 cm in length consuming aquatic wildfowl and mammals in comparison to smaller counterparts of <30 cm feeding on invertebrates and molluscs. Aquaculture, 243(1/4), 323-329. http://www.sciencedirect.com/science/journal/00448486, Kinzelbach R, 1992. Ulikowski, D., Borkowska, I., Chybowski, L., 1998. 2009Bevacqua et al. 4.5-5.5 ft.) but may reach lengths of up to 3 m (approx. Native to eastern Europe and western Asia it is now established in several countries to the west and south of its native range. Depending on the habitat the colouration may vary adding more or less accentuated shades, tending green and yellow. Hamácková, J., Kouril, J., Adámek, Z., Vachta, R., Stibranyiová, I., 1993. Global register of Introduced and Invasive species (GRIIS), Highly adaptable to different environments, Capable of securing and ingesting a wide range of food, Modification of natural benthic communities, Highly likely to be transported internationally accidentally, Highly likely to be transported internationally deliberately, Highly likely to be transported internationally illegally, Difficult to identify/detect in the field, Sport (hunting, shooting, fishing, racing), Meat/fat/offal/blood/bone (whole, cut, fresh, frozen, canned, cured, processed or smoked). Despite the great genetic differentiation of S. glanis populations, no consistent pattern of geographical structuring was revealed, in contrast to previous studies of European freshwater fish species. In adults, the gonads are 9-15% of total body weight. Sexual maturity is generally 3-4 yrs, between 39-71 cm length. Wels catfish are distinguishable by an elongated scale-less, slime-covered body, with strong upper body strength and laterally flattened tail. Biological Conservation, 72:311-319, Cucherousset, J., Boulêtreau, S., Azémar, F., Compin, A., Guillaume, M., Santoul, F., 2012. Status and development tendencies of freshwater aquaculture production in Bulgaria. “Silurus glanis is a commercial fish consumed by humans. Natural predators of S. glanis include otters (Lutra lutra), cormorants and waders, and other predatory fish such as pike (Esox lucius) and zander (Sander lucioperca). Bulgarian Journal of Agricultural Science, 4(6), 841-846. Some angling introductions are unregulated and illegal, with S. glanis transferred to unlicensed lakes in the UK that do not meet the ILFA (Import of Live Fish Act) criteria set by the Environment Agency because of risks concerning flooding and the likelihood of entry to nearby rivers. Le silure glane (Silurus glanis, L.) en France. Grozev, D., Hubenova-Siderova, T., Zaikov, A., 2000. Preliminary studies of intensive wels catfish (Silurus glanis L.) and sturgeon (Acipenser sp.) – Contenimento della presenza di Silurus glanis nelle acque dell’Adda ricomprese nel territorio del Parco Adda Nord e, nel comtempo, contenimento di altre specie ittiche alloctone dannose per l’equilibrio delle specie autoctone (come il gardon, il rodeo amaro, il carassio). This one has spotted a perch that most probably will meet a bad death © Sebastiano Guido. Pesticides should always be used in a lawful manner, consistent with the product's label. Large fish usually 1.3-1.6 m long (approx. It is the largest-bodied European freshwater fish (Copp et al., 2009). http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0050840 doi: 10.1371/journal.pone.0050840, Czarnecki, M., Andrzejewski, W., Mastynski, J., 2012. Following introduction outside its native range, the wels catfish has become established in Bosnia-Herzegovina, Spain, Denmark and Tunisia with some ecological effects. S. glanis cultivation has played a minor role in cyprinid pond farming. Wels catfish are also hosts of specialist parasites such as Trichodina siluri, Myxobolus miyarii, Leptorhynchoides plagicephalus and Pseudotracheliastes stellifer which may be detrimental to native fish survival (Copp et al. The eggs are large, about 1-3 mm in diameter (Copp et al., 2009). (Ucinkovitost dodatka polizyma na rast somovskog mlada (Silurus glanis) u kaveznom uzgoju). Age at maturity is 3-4 yrs. S. glanis is native to eastern Europe and western Asia (Kinzelbach, 1992), but is now established in at least seven countries to the west and south of its native range (Elvira, 2001). Removal of wels catfish from unlicensed lakes appears to be a priority for the Environment Agency in England and Wales, although how successful these measures are in practice has yet to be ascertained. The skin can be used in glue and leather manufacture. Also the caudal fin is little developped. S. glanis is also used in parts of Europe for aquaculture. 2001). In rosso e blu, i territori originari; in arancione, le zone dove è stato introdotto. S. glanis is robust enough during transport (even in minimal water and over considerable distances) to be translocated to areas outside its native geographical range (Copp et al., 2009). However it still accounts for only a small percentage of European freshwater aquaculture compared with the main species, rainbow trout (Oncorhynchus mykiss), brown trout (Salmo trutta) and common carp (Cyprinus carpio) -- total production of S. glanis was 602 tonnes in 1993, increasing to 2000 tonnes in 2002, and has since stabilised at >700 tonnes/year. S. glanis is cited as present in some rivers in the UK, e.g. There is a risk that wels catfish may impact on native fauna for a number of reasons.