European perch, redfin perch, river perch, Perca fluviatilus Linnaeus, 1758, Perca helvetica Gronow, 1854, Perca italica Cuvier, 1828, Perca vulgaris Schaeffer, 1761

Nonindigenous Occurrences:  Eurasian perch has been introduced to Australia (Welcomme 1988), China, Cyprus, Italy (Bianco and Ketmaier 2001), Morocco, New Zealand (Welcomme 1988), Spain, Portugal (Banha et al. 2015), and South Africa. It is stocked in Turkey (Coad 1996). It was introduced to Ireland hundreds of years ago.

Potential pathway(s) of introduction: Trans-oceanic shipping (ballast water)

Models developed by Kolar and Lodge (2002) predict that Perca fluviatilis will be introduced to the Great Lakes from the Ponto-Caspian basin by transoceanic shipping. Perca fluviatilis may be taken up by ballast water and survive in ballast tank environments. This species occurs in waters that have direct trade connections with the Great Lakes, such as the Baltic Sea (Ložys 2004, NBIC 2009). It is considered a eurythermal fish and can tolerate temperatures between 4-31°C (Toner and Rougeot 2008), but becomes stressed between 23-26°C (Lehtonen 1996). It occurs in waters with oxygen levels of 1.3 to 13.5 mg/L (Toner and Rougeot 2008). However, Perca fluviatilis cannot tolerate high salinities, so its survival in ballast tanks environments may be limited. It can inhabit brackish waters of the Aral and Baltic Sea, up to salinities of 10 ppt (Ložys 2004), and can survive salinities of 13 ppt at water temperatures of 12-15°C. Larvae cannot tolerate salinities greater than 9.6 ppt (Lehtonen 1996). Ballast water exchange regulations requiring flushing with full strength sea water of 35 ppt salinity may substantially limit the introduction of Perca fluviatilis to the Great Lakes. Perca fluviatilis may be introduced to the Great Lakes via ships declaring “No Ballast on Board” (NOBOB), which are exempt from ballast water exchange. The majority of ships entering the Great Lakes are NOBOB vessels and 43% of these ships contain residual water with less than 10 ppt salinity (NOAA Final Report 2005). In the study, the temperature of the residual water from the vessels sampled ranged from -0.7 to 23.9°C; thus Perca fluviatilis is likely to survive the salinity and temperature of the NOBOB ballast water on some vessels. 

As a prized freshwater angling species, Perca fluviatilis has been introduced to a number of countries (ISSG 2005). US EPA (2008) suggests that there is a high risk that Perca fluviatilis will be introduced to the Great Lakes region as a sport fish. Perca fluviatilis does not currently occur near waters connected to the Great Lakes basin. It is not known to hitchhike on ships or recreational gear. It is not stocked, cultured, or sold in the Great Lakes region. It may survive several hours out of water if packed in dry straw (Pinnock 1820).

Perca fluviatilis has a high probability of establishment if introduced to the Great Lakes (Confidence level: Moderate).

Eurasian perch occurs in Australia, which has a similar climate to most of the US, except for the Desert Southwest (USFWS Risk Summary 2012). Eurasian perch has a somewhat broad physiological tolerance. It is likely able to overwinter in the Great Lakes. This species is known to overwinter in Lake Constance, Germany, at temperatures between 4°–6°C, but may experience depletion of lipid reserves and post-spawning mortality as a result of overwintering (Eckmann 2004). Eurasian perch requires clear waters with a considerable level of light penetration to forage effectively (Granqvist and Mattila 2004). High nutrient levels and turbidity may be detrimental to the growth and survival of this species. It is predicted by Lehtonen (1996) that increased temperatures due to climate change will result in Eurasian perch spawning later in autumn and hatching earlier. In addition, it is expected that larvae will be smaller and will be more vulnerable to possible predators. Juveniles are predicted to grow to a larger size after their first summer due to warmer water temperatures. In contrast, Eurasian perch reach sexual maturity earlier in the southern hemisphere (non-native range) relative to the northern hemisphere (Morgan et al. 2002), likely due to warmer temperatures and greater prey availability. The shift of Eurasian perch to piscivory also begins earlier in the southern hemisphere, increasing its establishment success (Wedderburn et al. 2016). A climate change case study in Curonian lagoon, Lithuania revealed that European perch preferred brackish water (salinity 3–6‰) over freshwater and warmer water (18°C) over cooler water (12°C), but had no change in growth rate between water conditions (Dainys et al. 2019). Further, across 52 boreal European lakes fish biomass production decreased as temperature increased from 16 to 22°C and lake color darkened (van Dorst et al. 2019). Higher temperatures may constrict oxygen uptake in larger individuals, promoting smaller body sizes in warming waters (Christensen et al. 2020).

Eurasian perch is carnivorous and feeds on a wide variety of foods including zooplankton, insect larvae, crustaceans, and small fish (Toner and Rougeot 2008). Larvae feed on algae and zooplankton. It is likely that this species will find an appropriate food source in the Great Lakes. In its native range, Eurasian perch exhibits interspecific competition for food with the invasive ruffe, Gymnocephalus cernua (L.)(Erkmann 2004; Schleuter 2007) which also occurs as a non-native in the Great Lakes. Both species are benthic feeders at some point of their development and both inhabit the littoral zone. Eurasian perch is a visually oriented predator and competition favors it in oligotrophic conditions. On the other hand, the ruffe is favored in more eutrophic conditions and can feed in turbid environments. When ruffe is the superior competitor, there is a decline in the growth and yields of Eurasian perch.

If introduced into the Great Lakes, Eurasian perch will be likely prey for native piscivores, including pike. The extent to which these predators may suppress the establishment of Euraisan perch is unknown. In laboratory trials, Eurasian perch exhibited group defense behavior and were more resistant to predation by pike than Amur sleeper (Perccottus glenii) (Smirinov et al. 2019). In aquarium experiments, Eurasian perch adapted its habitat use to avoid that of pike and ruffe, both of which are potential predators and competitors of Eurasian perch (Henseler et al. 2020).

Eurasian perch has reproductive traits that could support its establishment in the Great Lakes. It has an average relative fecundity of102,000 eggs/kg of body weight which is comparable to a similar species native to the Great Lakes, Perca flavescens (79,000–223,000 eggs/kg) (Sheri and Power 1969). Both perch species’ egg strands are generally considered unpalatable biological material, thus making them resistant to predation (Vejrik et al. 2017).

Kolar and Lodge (2002) developed models that predicted that Eurasian perch has a high risk for establishment, will spread quickly, and will be a nuisance in the Great Lakes. Eurasian perch has been introduced to several countries including Australia, South Africa, China, Cyprus, Ireland, Italy, Morocco, New Zealand, Spain, and South Africa for its reputation as an angling species (Welcomme 1988). Eurasian perch growth is stunted in some waters in Cyprus. In New Zealand, it is reproducing artificially. The introduction of Eurasian perch to South Africa is considered marginally successful. Non-native Eurasian perch successfully colonized the mediterranean Lake Skadar within 35 years of introduction, and are the dominant fish in littoral habitats in both the northern and southern parts of the lake (Mrdak et al. 2018).

In Australia, Eurasian perch tends to outcompete native species (Welcomme 1988). It is a potential competitor with other fish that feed on invertebrates and small fish including Great Lakes native fish, such as brook trout, lake whitefish, and bluegill (Thorpe 1977). New South Wales, Australia considers Eurasian perch a noxious fish due to their ability to eliminate other fish species and for their negative impacts on recreational fisheries (NSWDPI 2012).

Summary of species impacts derived from literature review. Click on an icon to find out more...

Environmental	Socioeconomic	Beneficial

Eurasian perch is a carrier of the epizootic haematopoietic necrosis (EHN) virus. In Australia, the EHN virus carried by Eurasian perch may have resulted in declines of the native Macquarie perch (Macquaria australasica), silver perch (Bidyanus bidyanus), Murray cod (Maccullochella peelii), and mountain galaxias (Galaxias olidus) (Lintermans 1991; NSWDPI 2012). In a laboratory study, individuals carrying the EHN virus and viral haemorrhagic septicaemia virus (VHSV) had high rates (>90%) of survival and are thought to be resistant to the the fatal effects of these diseases (Pascoli et al. 2015). Further, Eurasian perch exposed to EHNV in the laboratory prior to release into an infected water body showed increased resistance to contracting the virus and to mortality (Becker et al. 2016). Disease resistance may be attributed to the high genetic diversity of some Eurasian perch populations and could help limit disease spread to other species (Faulks and Ostman 2016).

Eurasian perch can carry Perch rhabdovirus (Wahli et al. 2015; Caruso et al. 2019) which has caused major losses in the aquaculture of European perch (Dorson et al. 1984, Betts et al. 2003) and also infects grayling fry (Thymallus thymallus) (Gadd et al. 2013). A list of pathogens that infected Eurasian perch in a recirculating aquaculture system can be found in Rupp et al. (2019).

Eurasian perch can potentially compete with native species for zooplankton, macroinvertebrates, and fish (Closs et al. 2003). Eurasian perch is a strong competitor for invertebrates with the common goldeneye duck (Bucephala clangula) (Nummi et al. 2016). This species is said to compete for food and space with the Murray cod and golden perch (Macquaria ambigua) (Lintermans et al. 1990; Wedderburn et al. 2015). In New Zealand, Eurasian perch suppressed populations of a native fish, the common bully (Gobiomorphus cotidianus), by direct predation (Closs et al. 2003). Physical removal of Eurasian perch from ponds resulted in an increased abundance of the common bully. It has been suggested that Eurasian perch competition is responsible for the local extinction of the rare mud minnow, Galaxiella munda (NSWDPI 2012). It has been reported that Eurasian perch preyed on native pygmy perch (Edlia vittata) in Australia, negatively impacting their populations (Arthington and McKenzie 1997). It is suspected that Eurasian perch negatively affects native fish populations by preying on vulnerable Ewen’s pygmy perch, Nanoperca variegata, vulnerable Yarra pygmy perch, Edelia obscura, the vulnerable dwarf Galaxia, Galaxias pusilla, and juveniles of Macquarie perch. Populations of the southern pygmy perch (Nannoperca australis) suffered greatly from predation by invasive species such as Eurasian perch (NSWDPI 2015).

Invasions of Eurasian perch may alter food web dynamics. In the Vír Reservoir, Czech Republic, the high abundance of young-of-year Eurasian perch decreased Daphnia spp. size and abundance, resulting in the poor nutritional conditions of bream. The lack of Daphnia spp. also initiated a shift in Eurasian perch to forced piscivory of bream and common carp  (Vejrik et al. 2016).

Perca fluviatilis has the potential for moderate socio-economic impact if introduced to the Great Lakes.

Eurasian perch may prey on native species and trout, negatively affecting recreational fisheries. Within a 72-hour period, Eurasian perch eliminated 20,000 newly released rainbow trout (Oncorhynchus mykiss)  fry from a reservoir in south-western Australia (NSWDPI 2012). In Italy, Eurasian perch is host to the digenean trematode, Clinostomum complanatum, which is responsible for Halzoun syndrome in humans who consume raw or undercooked fish (Menconi et al. 2020).

Perca fluviatilis has the potential for high beneficial impact if introduced to the Great Lakes.

Eurasian perch is valued as an important fish species for aquaculture, fisheries, and recreation (Setälä et al. 1996; Toner and Rougeot 2008). In Europe, Eurasian perch are a valuable commercial and recreational freshwater fish species (Vainikka et al., 2012; Heerman et al. 2013). It is one of the most economically important fish species for freshwater and Baltic sea fisheries in Estonia (OECD 2009). Gelatin extracted from Eurasian perch has a high gel strength, melting point, and water-holding and fat-binding capacity making it a potential replacement for mammalian gelatin in the food industry (Hue et al. 2017).

Eurasian perch were used as a biocontrol agent for the topmouth gudgeon (Pseudorasbora parva) in England. Predation pressure by Eurasian perch continually suppressed abundance of topmouth gudgeon and was significantly more effective than physical removal methods (Davies and Britton 2015). In their native range (Musov reservoir), Eurasian perch shifted their predation from cyprinids to the recently introduced non-native tubenose goby, potentially limiting invasion success (Vseticková et al. 2018). Eurasian perch were also used as a successful biocontrol agent of non-native Amur sleeper in four small Lithianian lakes (Rakauskas et al. 2019).

Federally banned in the United States from import and trade (including all hybrids) under the Lacey Act. Perca fluviatilis is prohibited in Minnesota, making it a misdemeanor to possess, import, purchase, transport, or introduce the species in the state (§ 84D.07). In Ohio, it is listed as invasive and is unlawful for any person to possess, import or sell live individuals of this species (Ohio Administrative Code 1501:31-19-01).

Note: Check federal, state/provincial, and local regulations for the most up-to-date information.

Control

Biological
There are no known biological control methods for this species.

Physical
Repeated removal by netting successfully suppressed Eurasian perch biomass in a small lagoon (7.5 ha) with one or two intensive removal events per year timed with spawning (McEwan et al. 2019).

Chemical
There are no known chemical control methods specific to this species. General piscicides (such as rotenone) may be used for control, but expect significant kill of non-target species.

Note: Check state/provincial and local regulations for the most up-to-date information regarding permits for control methods. Follow all label instructions.