Perccottus glenii
(Amur sleeper)

Pictures

Picture	Title	Caption	Copyright
Title Female Caption Perccottus glenii: female Amur sleeper. Copyright Michal Grabowski	Female	Perccottus glenii: female Amur sleeper.	Michal Grabowski
Title Male Caption Perccottus glenii: male Amur sleeper. Copyright Michal Grabowski	Male	Perccottus glenii: male Amur sleeper.	Michal Grabowski
Title Female Caption Perccottus glenii: female Amur sleeper. Copyright Joanna Grabowska	Female	Perccottus glenii: female Amur sleeper.	Joanna Grabowska
Title Male Caption Perccottus glenii: male Amur sleeper. Copyright Joanna Grabowska	Male	Perccottus glenii: male Amur sleeper.	Joanna Grabowska

Identity

Preferred Scientific Name

• Perccottus glenii Dybowski, 1877

Preferred Common Name

• Amur sleeper

Other Scientific Names

• Eleotris dybowskii Herzenstein & Warpachowski, 1887
• Eleotris dybowskii Warpachowski, 1887
• Percottus glehni Dybowski, 1877

International Common Names

• English: Chinese sleeper; rotan

Local Common Names

• Finland: rohmutokko
• Germany: Chinesische; Schlafergrundel
• Hungary: Amur géb; Amurgéb
• Netherlands: Amurgrondel
• Poland: trawianka
• Russian Federation: goloveshka; rotan, goloveshka
• Serbia: Amurskog spavaca
• Slovakia: byckovec hlavaty

Summary of Invasiveness

The Amur sleeper is considered as one of the most widespread (Reshetnikov, 2010) and successful fish invaders in European inland waters of the last decades (Copp et al., 2005). Since 1916 when the species was introduced outside its native range of distribution for the first time,  it expanded to 15 countries in Eurasia (almost the whole of Russia, Mongolia, Belarus, Ukraine, Lithuania, Latvia, Estonia, Poland, Hungary, Romania, Slovakia, Serbia, Bulgaria, Moldova and Croatia) where it has been recorded from the rivers Volga, Ural, Don, Dnieper, Dniestr, Vistula, Danube, Pregolya, Nemen, Daugava, Velikaya, Neva, Onega, North Dvina, Ob and Enisey (Reshetnikov, 2010). The rate of the Amur sleeper expansion is impressive - the rate of its expansion in the Vistula River ranged from an initial 44 km per year, up to 197 km per year thereafter (mean ~ 88 km per year). The Amur sleeper is voracious predator that forages on a wide range of prey from small planktonic invertebrates (Cladocera, Copepoda consumed by juveniles), through macroinvertebrates (larvae of Insecta, Oligochaeta, Mollusca, Crustacea) to vertebrates (fish and amphibian larvae: Triturus sp., Rana sp.). Its impact on the environment in invaded areas is sometimes described as deteriorative as it is able to exhaust the entire food supplies, and also can compete with native species for the same food resources (Spanovskaya et al., 1964; Litvinov and O’Gorman, 1996; Reshetnikov, 2001; 2003). Thus, it can considerably affect the tropic structure of some water bodies and even lead to local extinction of some species or, at least, decrease of their abundance. The Amur sleeper was brought intentionally to European part of Russia and later released to open waters, from where it naturally penetrated farther. The species was also kept in aquaria and used as live bait - such activities could be additional reasons for uncontrolled introductions. It was also accidentally introduced several times to many distant localities as contamination of stocking material of Asian herbivorous cyprinids (Reshetnikov, 2004, 2010; Reshetnikov and Ficetola, 2011). 

Considering its widespread and rapid invasion in Eurasia and its potential impact on native biota it was placed on the list of the top 27 animal alien species introduced into Europe for aquaculture and related activities. This list includes species that could cause serious thread to biodiversity if they escaped to open water bodies (Savini et al., 2010).

Taxonomic Tree

• Domain: Eukaryota
•     Kingdom: Metazoa
•         Phylum: Chordata
•             Subphylum: Vertebrata
•                 Class: Actinopterygii
•                     Order: Perciformes
•                         Suborder: Gobioidei
•                             Family: Odontobutidae
•                                 Genus: Perccottus
•                                     Species: Perccottus glenii

Notes on Taxonomy and Nomenclature

The specific epithet glenii is derived from the surname of the original collector, Glen, it may be misspelled as glehni or glenhi. Previously it has been placed in family Eleotridae (Berg, 1949; Nikolski, 1956).

Description

Amur sleeper is a small/medium fish up to 20-25 cm total length. The shape of the body is typically streamlined like a perch. The body is robust, the depth at pelvic origin being about 30% of standard length. The mouth is large, the angle of the jaws is below the rear half of eye, the lower jaw is in advance of the upper jaw; the upper lip more or less uniform in width; the teeth are caniform. As with all fish from the Perciformes it has two dorsal fins. The pectoral fin tip is below the origin of the second dorsal fin. The pelvic fins are relatively short, less than 1/2 to 3/4 the length of the abdomen and about 3/5 to 3/4 of pectoral fin length. The caudal fin is rounded (Miller and Vasil’eva, 2003). The whole body is scaled. The meristic features for Amur sleeper are: D₁ VI-VIII, D₂ I-II/9-11, A I-III/7-10, P 14-16, V I/5 scales in lateral line l.l. 37-43 (Kirpichnikov, 1945; Berg, 1949; Miller and Vasil’eva, 2003).

Its coloration is rather dark and varies from greenish-olive to brownish-grey or dark green depending on water body character and colour of substrate. On the dorsal and lateral sides of the body it has dark, irregular spots and blotches with numerous small pale yellow to blue-green flecks; the belly speckled. A dark streak runs from the tip of snout to edge of opercula and from eye to angle of jaws.

The first dorsal fin has 3-4 dark pigmented streaks and similar pattern can be found on the caudal and anal fins. The dimorphism between the sexes (apart from during the breeding season) is not easily visible. The dorsal fins of males are slightly larger and closer to each other than in females. The ventral fins also differentiate the sexes as they are shorter and of different shape in males. Breeding males are much darker than females, sometimes almost black with distinct irregularly scattered bright bluish-green spots. Spots of the same colour, but arranged in even, horizontal rows are present on the dorsal and anal fins. Also in the breeding season males have inflated areas on the head.

Distribution

The Amur sleeper’s natural range of distribution is situated in north-eastern China, the northern part of North Korea and in the Far East of Russia. It includes mainly the Amur River basin, i.e. tributaries like Zeya, Sunguri and Ussuri. In the north the natural range reaches the Uda River (Reshetnikov, 2010) and the basin of the Tugur River and in the south the species is known from rivers of the Sea of Japan (Bogutskaya and Naseka, 2002 after Reshetnikov, 2001). Due to accidental introductions and further natural migration the Amur sleeper has invaded many localities in Eurasia: Russia, Latvia, Lithuania, Estonia, Ukraine, Moldova, Mongolia, Poland, Hungary, Slovakia, Romania, Bulgaria, Serbia and Croatia. The earlier records from Kazakhstan and Uzbekistan were based on misidentification of another related species Micropercops cinctus (Odontobutidae), because of similar appearance. Later ichthyological surveys in south-eastern Kazakhstan and Uzbekistan have failed to detect Amur sleeper (Mitrofanov et al., 1992; Reshetnikov, 2010).

Its present non-native distribution range covers the area between 44-63°N; 17-121°E (Reshetnikov, 2010). The most northern record is from Plestsy Lake in Arkhangels province (Russia), while the most southern finding in western Eurasia is in Bulgaria. The most western record for this species is from the Kis-Balaton watershed (Hungary) (Antal et al., 2009).

Distribution Table

The distribution in this summary table is based on all the information available. 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.

History of Introduction and Spread

The species first documented introduction outside its natural range distribution comes from 1912 when it was brought by the Russian naturalist I.L. Zalivskii near St. Petersburg (Lisiy Nos settlement) and four years later some individuals were released to a garden pond, from which they spread to other waterbodies (see Reshetnikov, 2001). In 1948, another introduction took place, the species was brought to Moscow by the participants of the Amur expedition (Spanovskaya et al., 1964; Bogutskaya and Naseka, 2002; Reshetnikov, 2004). Soon it appeared in the aquaria of amateurs and next in several ponds in Moscow and the Moscow Province. The other introductions were more unintentional as the Amur sleeper was translocated as contamination of stocking material of Asian herbivorous cyprinids e.g. Cyprinus carpio to fish farms from where it penetrated to open waters. One of the earliest examples of such introduction was the expansion of Amur sleeper from the Khabarovsk fish farm (Far East of Russia) to Gusinoe Lake (the Lake Baikal basin) in 1969. Similarly, it penetrated from the Ilevsk fish farm to waterbodies of the Nizhniy Novgorod Province in 1970-1971. Reshetnikov and Ficetola (2011) distinguished 13 centres of the Amur sleeper distribution outside of its native range - their location determined the shape of the current invaded range. According to these authors the invasion centre of Amur sleeper for Central Europe, i.e. Ukraine, Poland, Slovakia, Hungary, Serbia, Romania and Bulgaria, might be the fish farm near Lviv (Ukraine), where Amur sleeper had been introduced before 1980. However the series of independent accidental introductions of Amur sleeper (as contamination of stocking material) from different locations, including areas of the species native range distributions, is also possible considering the intensity of trade of stocking material of Asian cyprinids and number of purposeful introductions of these commercially important species both to ponds and open waters.

Introductions

Risk of Introduction

According to recent studies of Reshetnikov and Ficetola (2011), there are many possible areas in Eurasia at high risk of the Amur sleeper invasion due to the high suitability of bioclimatic conditions. Although the mountain regions of Europe constitute a barrier to this species, two corridors may connect already colonized areas to Western Europe: a first corridor that includes the Vistula, Notec and Oder rivers through the system of canals in Germany to the Labe and Rhine rivers and further to Netherlands, Belgium, France, etc. (Reshetnikov and Ficetola, 2011; Semenchenko et al., 2011) and a second corridor extending from the Danube River basin through Croatia, Slovenia and Italy to France (Reshetnikov and Ficetola, 2011). Although the Amur sleeper is rare in large rivers it often inhabits flood plains and such rivers are common pathways for its dispersal, mainly during high water levels events. Thus large rivers serve as important long-distant downstream transmission corridors. As the species spreads across geographical barriers due to human-mediated introductions, e.g. as contamination of stocking material, many other locations characterized by suitable climatic conditions are at risk of Amur sleeper introduction such as Japan, the southern British Isles and parts of North America (Reshetnikov and Ficetola, 2011).

Habitat

The Amur sleeper is a limnophilic species, inhabiting freshwater canals, gravel pits, natural and fish ponds. It lives in the littoral zone of these waterbodies. It prefers rather stagnant waters with dense aquatic vegetation and muddy substrate; in rivers it avoids the main current and is common in flood plains and oxbow lakes. It tolerates low oxygenation of water, so it can be found also in drying, shallow waterbodies. It usually co-occurs with gibel carp (Carassius gibelio), crucian carp (Carassius carassius) and mud loach (Misgurnus fossilis).

Habitat List

Biology and Ecology

Genetics

An analysis of the mitochondrial DNA of this species is included in Thacker and Hardman (2005).

Reproductive Biology

The Amur sleeper’s life span is 7-10 years but in most populations studied, both in natural and non-native areas, individuals older than 4+ were not found (Bogutskaya and Naseka, 2002; Miller and Vasil’eva, 2003). Seven age classes were distinguished in the Selenga River (the Baikal drainage, Russia) (Litvinov and O’Gorman, 1996) and also in Wloclawski Reservoir (located in lower section of the Vistula River, Poland) (Grabowska et al., 2011).

The age of maturation observed in its natural range is 2+ and 3+ (Kirpichnikov, 1945; Nikolski, 1956) while in most introduced areas fish matured at the age 2+, although specimens maturing in the second year of life were also found (Spanovskaya et al., 1964; Litvinov and O’Gorman, 1996). The growth rates of Amur sleeper vary considerably in its geographic range (see for review Grabowska et al., 2011). Amur sleeper is a multiple spawner (at least two batches); however, large females spawn longer during the breeding season and deposit more batches of eggs. The spawning starts when water temperatures exceed 15°C and in the Amur River (native area) last from May to June (Kirpichnikov, 1945). The spawning season in the Wloclawski Reservoir was longer than that recorded for the Amur sleeper in its natural and introduced range, and lasted almost three months longer than in other regions (Bogutskaya and Naseka, 2002; Miller and Vasil’eva, 2003), i.e. from April to August. Fecundity depends on female size. In a two-year-old female at 6.3 cm fecundity ranges from 1000 to 2000 mature oocytes plus over 2000 immature oocytes; however, it can range from 150 to 20,000 (Elovenko, 1985). In the Selenga River (Lake Baikal basin), mean fecundity was found to range from 549 at one year (mean length 44 mm) to 19,765 at seven years (mean length 190 mm) (Litvinov and O’Gorman, 1996). At the beginning of the reproductive period (in April) the mean fecundity (Fa) was 7766 eggs per female and ranged from 1963 (at 48 mm SL) to 23,479 (at 129 mm SL) in the Wloclawski Reservoir (Grabowska et al., 2011). The egg diameter histograms for females at the beginning of spawning season in Wloclawski Reservoir revealed two size-groups of oocytes in gonads: small 0.1-0.9 mm and large 1.0-1.8 mm (Grabowska et al., 2011). Eggs are deposited on the lower surface of submerged objects: plants, stones, roots, etc. (litho-phitophilous species). Embryonic development lasts for 10-12 days at a water temperature of 19°C. Larvae on the day of hatching are 4.5-5.0 mm. After three days they can swim freely in the water column and start external feeding. The Amur sleeper provides parental care, as males guard their eggs until they hatch, as well as fanning the clutch with their pectoral fins and defending the nest aggressively (Bogutskaya and Naseka, 2002; Miller and Vasil’eva, 2003). 

The Amur sleeper displays a great variation in life history traits, which are in response to local environmental conditions. It has been hypothesized that the success of an invasive species can be strongly dependent on the plasticity of its life history traits.

Environmental Requirements

The Amur sleeper has low environmental requirements and it is very tolerant to many physical and chemical variables of water quality. It avoids strong water currents and prefers rather stagnant waters, densely overgrown with aquatic vegetation.

Climate

Water Tolerances

Natural enemies

Notes on Natural Enemies

The Amur sleeper might be a prey of common freshwater predators like northern pike (Esox lucius), perchpike (Sander lucioperca) and European perch (Perca fluviatilis) (Bogutskaya and Naseka, 2002). For example in the Lake Baikal basin these predators are suggested as regulators of Amur sleeper abundance.

The Amur sleeper is characterized by high parasite burdens over its entire range. In total, over 40 species of parasites have been reported for the Amur sleeper, including 15 protozoans, 4 monogenetic and 7 other trematodes, 8 cestodes, and 3 nematodes (Miller and Vasil’eva, 2003). Host specific parasites are the cestode Nippotaenia mogurndae (Yamaguti and Miyata, 1940) found in intestine (Košutová et al., 2004) and the monogenean parasite Gyrodactylus perccotti that infects the fins and opercula (Ondrackova et al., 2007). Both these parasites were detected outside the natural range of distribution of Amur sleeper.

Means of Movement and Dispersal

Natural Dispersal (Non-Biotic)

The Amur sleeper has naturally dispersed from several locations since its initial introduction. Reshetnikov and Ficetola (2011) distinguished 13 such dispersal centres for the present non-native distribution range. It is a rather bad swimmer and avoids main river courses; however, large rivers serve as long distance transport corridors downstream during high water levels and especially floods, when they are washed from adjacent oxbow lakes and flood plains, which they often inhabit (Košco et al., 2003a; Reshetnikov, 2010; Reshetnikov and Ficetola, 2011).

Accidental Introduction

The Amur sleeper has been accidentally introduced several times to many localities with stocking material of herbivorous cyprinids mainly Cyprinus carpio. It seems to be the most probable reason of its appearance in the Vistula and Danube river systems.

Intentional Introduction

The first specimens were translocated from their natural distribution area, i.e. the far east of Asia to Europe intentionally by a Russian naturalist and later by participants of Amur expeditions. The species is also known to be kept in aquaria (in Moscow in the 1950s it was available on a bird market) and was used as a live bait (Spanovskaya et al., 1964; Reshetnikov, 2004; 2010). Both were probably a source of uncontrolled local introductions by aquarists and anglers.

Pathway Causes

Pathway Vectors

Impact Summary

Economic Impact

Litvinov and O’Gorman (1996) suggest the potential negative influence of Amur sleeper presence in the Selenga River (the Lake Baikal basin) on commercially important fish species such as Siberian roach (Rutilus rutilus lacustris) and Siberian dace (Leuciscus leuciscus baicalensis), as these species must now share food resources with Amur sleeper. Siberian roach and Siberian dace together accounted for about 50% of weight of commercial harvest in the Barguzin commercial area (Litvinov and O’Gorman, 1996).

Environmental Impact

Impact on Biodiversity

Amur sleeper is a predator with morphological features that enable hunting of a large variety of aquatic organisms with inclusion of relatively big prey items (Miller and Vasil’eva, 2003). When evaluating the potential impact of this species on ecosystems it might be concluded that several taxonomic groups of native hydrofauna, both macroinvetebrates and vertebrates would be potentially affected by the presence of this new predator. Its diet has been studied mostly in its native range (Sinelnikov, 1976) as well as in some invaded ecosystems in Russia (Spanovskaya et al., 1964; Litvinov and O’Gorman, 1996; Reshetnikov, 2001; 2003; 2008), Slovakia (Košco et al., 2008) and Poland (Grabowska et al., 2009). In all cases the species is reported to be a voracious predator with broad diet, constituting of crustaceans (Cladocera, Copepoda, Malacostraca), larvae and imagos of insects (Ephemeroptera, Odonata,  Hemiptera, Diptera, Trichoptera, Coleoptera), molluscs, fish and even larvae of amphibians (frogs and newts). Effects of the species predation on local aquatic communities in Russia were reported as deteriorative (Spanovskaya et al., 1964; Reshetnikov, 2001; 2003; 2008). Reshetnikov (2001; 2003) revealed that in small waterbodies Amur sleeper depressed populations of macroinvertebrates, as well as other fishes (e.g. Carassius carassius, Leucaspius delineatus), newts (Triturus cristatus, T. vulgaris) and frogs (Rana temporaria, R. arvalis, R. lessonae) that cannot reproduce successfully due to predation pressure, as the result the negative correlation between the presence and abundance of Amur sleeper and species richness of aquatic animals was observed. Long-term studies near Moscow (Spanovskaya et al., 1964) showed that the composition of consumed food changed along with alterations caused by Amur sleeper in local communities of available prey species. After abrupt impoverishment of large invertebrate fauna, and elimination of eggs, larvae and juveniles of crucian carp, tadpoles appeared in the predator’s diet and cannibalistic behaviour was noted. This shows Amur sleeper is an effective “switch-predator”.

Among hunted fish in the Wloclawski Reservoir (Poland) the most prevalent prey were cyprinids: bitterling Rhodeus sericeus, bleak Alburnus alburnus and roach Rutilus rutilus (Grabowska et al., 2009). According to Zaloznykh (1984), Amur sleeper preferred enamoured fish preys as compared to those that possess spines. However, in guts of large individuals from the Wloclawski Reservoir some sticklebacks, and even remains of spiny-cheek crayfish Orconectes limosus were also found in spring, probably because juveniles of unarmoured fish species were not available yet (Grabowska et al., 2009).

For some fish species native to central Europe like Umbra kramerii, Leucaspius delineatus, Carassius carassius, Rhodeus sericeus and larvae of other species, the Amur sleeper is a real threat not only due to predation but also as regards trophic competition (Košco et al., 2003b). It essentially causes them to disappear from the localities invaded by Amur sleeper. Under special concern should be native species of high conservation status like the mud minnow Umbra krameri in Slovakia and the swamp minnow Eupallasella percnurus in Poland (Wolnicki and Kolejko, 2008) as they show similar microhabitat requirements with Amur sleeper. These endangered and regionally highly endangered species locally suffer from Amur sleeper presence mainly due to predation. Similarly, in the Selenga River (the Lake Baikal basin) the invasion of Amur sleeper is expected to cause population decline of endemic fish species (Siberian roach, Rutilus rutilus lacustris and Siberian dace, Leuciscus leuciscus baicalensis) through resource competition and predation on their juveniles (Litvinov and O’Gorman, 1996).

It is expected that the recent rapid expansion of Amur sleeper in Central European waters will cause a serious threat to local aquatic communities.

Threatened Species

Risk and Impact Factors

• Proved invasive outside its native range
• Has a broad native range
• Highly adaptable to different environments
• Is a habitat generalist
• Capable of securing and ingesting a wide range of food
• Highly mobile locally
• Fast growing
• Has high reproductive potential

• Altered trophic level
• Modification of natural benthic communities
• Modification of nutrient regime
• Negatively impacts aquaculture/fisheries
• Reduced native biodiversity
• Threat to/ loss of endangered species
• Threat to/ loss of native species

• Competition - monopolizing resources
• Interaction with other invasive species
• Predation

• Highly likely to be transported internationally accidentally
• Highly likely to be transported internationally illegally
• Difficult/costly to control

Uses

The Amur sleeper does not have any human uses, economic value and social benefits, apart from use as bait (see Reshetnikov, 2001).

Uses List

Animal feed, fodder, forage

• Bait/attractant

Prevention and Control

Eradication

According to Litvinov and O’Gorman (1996), the elimination of the Amur sleeper from Lake Baikal is not possible since it has established a reproductive population and any attempts to eliminate exotic species in such cases are rarely successful.

Experiments by Zaloznykh (1984) have shown that Amur sleeper is the most resistant species of all fish treated with lime chloride (CaCl₂) and ammonia water (NH₄OH). One hundred per cent death of Amur sleeper occurs when the concentration of CaCl₂ is 0.3 g per litre of water at exposure of not less than 6 hours. However, this practice may only be done in small pools e.g. fish ponds. The ammonia water also works well. At water temperatures of 7-8°C and pH 9.0 100% death of Amur sleeper occurred in 1 hour after 1 ml of NH₄OH was added to one pool.

References

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Contributors

15/08/11 Original text by:

Joanna Grabowska, Dept. of Invertebrate Zoology and Hydrobiology, University of Lodz, Poland

Reviewers' names are available on request.

Distribution Maps