Cercopagis pengoi (fishhook waterflea)
- Summary of Invasiveness
- Taxonomic Tree
- Distribution Table
- History of Introduction and Spread
- Risk of Introduction
- Habitat List
- Biology and Ecology
- Water Tolerances
- Natural enemies
- Notes on Natural Enemies
- Means of Movement and Dispersal
- Pathway Causes
- Pathway Vectors
- Impact Summary
- Economic Impact
- Environmental Impact
- Social Impact
- Risk and Impact Factors
- Similarities to Other Species/Conditions
- Prevention and Control
- Gaps in Knowledge/Research Needs
- Links to Websites
- Distribution Maps
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PicturesTop of page
IdentityTop of page
Preferred Scientific Name
- Cercopagis pengoi Ostroumov, 1891
Preferred Common Name
- fishhook waterflea
Other Scientific Names
- Cercopagis (Apagis) ossiani Mordukhai-Boltovskoi, 1968
International Common Names
- English: spiny water flea
- Russian: cercopag
Local Common Names
- Estonia: sabaloom
- Finland: petovesikirppu
- Germany: Kaspischer Wasserfloh
- Latvia: angelhaken-cerkopagis
- Lithuania: Cercopagis
- Poland: wioslarka kaspijska
- Sweden: rovvattenloppa
Summary of InvasivenessTop of page
C. pengoi is a predatory cladoceran. The species tolerates a broad range of salinity, temperature and eutrophication conditions and is highly invasive. In addition, the “resting eggs” of this water flea can be transported over long distances, and can even survive cold winters on the sea bed. C. pengoi is native to the Ponto-Aralo-Caspian Basin. It has become invasive in eastern Europe, the Baltic Sea and the Great Lakes of North America. The species was first time noted as invasive in the Tsimlyansk Reservoir in Russia in 1970 (Glamazda, 1971). In these new habitats the species has established quickly and increased in range and abundance.
Taxonomic TreeTop of page
- Domain: Eukaryota
- Kingdom: Metazoa
- Phylum: Arthropoda
- Subphylum: Crustacea
- Class: Branchiopoda
- Order: Cladocera
- Suborder: Onychopoda
- Family: Cercopagidae
- Genus: Cercopagis
- Species: Cercopagis pengoi
DescriptionTop of page
C. pengoi is greyish white and almost transparent. The body is about 1-2 mm long which contrasts with its 10 mm long tail. The most pronounced parts of its body are the head, the second pair of antenna (containing two branches), four pairs of thoracic legs (the first leg is 3-4 times longer than other legs), abdomen, caudal process and a brood pouch in females. The head is essentially composed of a large single eye, where the amount of black pigment makes less than one half of the diameter of the eye. The length of the abdomen is about equal to that of the remaining body (the caudal process excluded). The long caudal process has a loop-like curvature at the end (Mordukhai-Boltovskoi and Rivier, 1987; Rivier 1998). Parthenogenic females of the first generation of C. pengoi that hatch from resting eggs are anatomically distinct from parthenogenic females of following generations. They have a short, straight caudal spine unlike the characteristically looped caudal spine of parthenogenically-produced individuals (Simm and Ojaveer, 1999).
DistributionTop of page
For a recent study of C. pengoi in the Gulf of Gdansk see Bielecka and Mudrak (2010).
Distribution TableTop of page
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.
|Continent/Country/Region||Distribution||Last Reported||Origin||First Reported||Invasive||Reference||Notes|
|Atlantic, Northeast||Localised||Introduced||Invasive||Olenin et al., 2002||Widespread in the Baltix Sea area especially in the Baltic Proper, the Gulf of Riga, the Gulf of Finland, Vistula Lagoon and the Gulf of Bothnia|
|Mediterranean and Black Sea||Localised||Native||Not invasive||Mordukhai-Boltovskoi and Rivier, 1987; Kane et al., 2003|
|Kazakhstan||Localised||Native||Not invasive||Mordukhai-Boltovskoi and Rivier, 1987||Aral Sea|
|Turkey||Localised||Native||Invasive||Guher, 2004||Lake Terkos|
|Canada||Present||Present based on regional distribution.|
|-Ontario||Widespread||Introduced||Invasive||MacIsaac et al., 1999; Therriault et al., 2002|
|USA||Present||Present based on regional distribution.|
|-Illinois||Widespread||Introduced||Invasive||MacIsaac et al., 1999||Lake Michigan|
|-Indiana||Widespread||Introduced||Invasive||MacIsaac et al., 1999||Lake Michigan|
|-Michigan||Widespread||Introduced||Invasive||MacIsaac et al., 1999; Therriault et al., 2002|
|-New York||Widespread||Introduced||Invasive||MacIsaac et al., 1999; Therriault et al., 2002; Laxson et al., 2003|
|-Ohio||Widespread||Introduced||Invasive||Therriault et al., 2002||Lake Erie|
|-Wisconsin||Widespread||Introduced||Invasive||MacIsaac et al., 1999||Lake Michigan|
|Bulgaria||Localised||Native||Invasive||Guher, 2004||Coastal Lakes|
|Estonia||Widespread||Introduced||Invasive||Kotta et al., 2004||First recorded in Parnu Bay, the Gulf of Riga|
|Finland||Widespread||Introduced||Invasive||Uitto et al., 1999|
|Germany||Localised||Introduced||Invasive||ICES, 2005||Pomeranian Bay|
|Latvia||Widespread||Introduced||Invasive||Strake, 2002||The Gulf of Riga, the Baltic Sea Proper|
|Lithuania||Widespread||Introduced||Invasive||NOBANIS, 2007||Curonian Lagoon|
|Poland||Localised||Introduced||Invasive||Zmudzinski, 1999||Gulf of Gdansk, Vistula Lagoon|
|Romania||Widespread||Native||Not invasive||Cristescu et al., 2001||Black Sea, Golovita Lake, Razelm Lake|
|Russian Federation||Present||Present based on regional distribution.|
|-Northern Russia||Widespread||Introduced||1995||Invasive||Bychenkov and Rodionova, 1996||Neva Estuary|
|-Southern Russia||Widespread||Native||Not invasive||Cristescu et al., 2001||Caspian Sea|
|Sweden||Widespread||Introduced||Invasive||Gorokhova et al., 2000||Northern Baltic Proper, Gulf of Bothnia|
|Ukraine||Present||Cristescu et al., 2001; Makarewicz et al., 2001|
History of Introduction and SpreadTop of page
Introductions occur either due the construction of canals between river water basins (mainly those in Russia and the Ukraine), ballast water discharge (Baltic Sea and the Great Lakes) or boat traffic (within the region of the Great Lakes). All introductions are accidental.
Risk of IntroductionTop of page
Due to its broad environmental tolerance and ability to reproduce parthenogenetically the risk of introducing C. pengoi to new regions is high.
HabitatTop of page
C. pengoi inhabits lakes, estuaries and offshore marine habitats. C. pengoi has a wide tolerance to salinity (from freshwater to 17 practical salinity units (psu)) and temperature (3-38ºC) (Gorokhova et al., 2000). The highest population densities are usually found at temperatures of 16-26ºC and at salinities of up to 10 ‰ (Mordukhai-Boltovskoi and Rivier, 1987; Rivier, 1998). Both in the Caspian Sea (Rivier, 1998) and Lake Ontario (Ojaveer et al. 2001) the abundance of C. pengoi increases with distance from shore suggesting that this is a typical pelagic species. In the Caspian Sea, C. pengoi performs diurnal vertical migrations. During the daytime they sink down to 50-60 m and at night they move up to the surface. Newly-born individuals do not descend deeper than 20-30 m (Mordukhai-Boltovskoi and Rivier, 1987). However, there is no evidence of diurnal migrations of C. pengoi in the Baltic Sea (Krylov et al., 1999).
Habitat ListTop of page
|Coastal areas||Principal habitat||Harmful (pest or invasive)|
|Coastal areas||Principal habitat||Natural|
|Irrigation channels||Principal habitat||Harmful (pest or invasive)|
|Lakes||Principal habitat||Harmful (pest or invasive)|
|Reservoirs||Principal habitat||Harmful (pest or invasive)|
|Estuaries||Principal habitat||Harmful (pest or invasive)|
|Lagoons||Principal habitat||Harmful (pest or invasive)|
|Inshore marine||Principal habitat||Harmful (pest or invasive)|
|Inshore marine||Principal habitat||Natural|
|Pelagic zone (offshore)||Principal habitat||Harmful (pest or invasive)|
|Pelagic zone (offshore)||Principal habitat||Natural|
Biology and EcologyTop of page Genetics
Physiology and Phenology
ClimateTop of page
|BS - Steppe climate||Preferred||> 430mm and < 860mm annual precipitation|
|BW - Desert climate||Preferred||< 430mm annual precipitation|
|Cs - Warm temperate climate with dry summer||Preferred||Warm average temp. > 10°C, Cold average temp. > 0°C, dry summers|
|Ds - Continental climate with dry summer||Preferred||Continental climate with dry summer (Warm average temp. > 10°C, coldest month < 0°C, dry summers)|
Water TolerancesTop of page
|Parameter||Minimum Value||Maximum Value||Typical Value||Status||Life Stage||Notes|
|Depth (m b.s.l.)||0||60||Optimum|
|Salinity (part per thousand)||0||10||Optimum||0-17 tolerated|
|Water temperature (ºC temperature)||16||26||Optimum||3-38 tolerated|
Natural enemiesTop of page
|Natural enemy||Type||Life stages||Specificity||References||Biological control in||Biological control on|
|Alburnus alburnus||Predator||Adult||not specific|
|Alosa pseudoharengus||Predator||Adult||not specific|
|Clupea harengus membras||Predator||Adult||not specific|
|Gasterosteus aculeatus aculeatus||Predator||Adult||not specific|
|Osmerus eperlanus||Predator||Adult||not specific|
Notes on Natural EnemiesTop of page
C. pengoi is preyed by a number of pelagic fish species. C. pengoi competes with a number of nectobenthic mysids and fish larvae for food (Kotta et al., 2004, 2006).
Means of Movement and DispersalTop of page Natural Dispersal (Non-Biotic)
Pathway CausesTop of page
Pathway VectorsTop of page
Impact SummaryTop of page
Economic ImpactTop of page
C. pengoi interferes with fisheries by clogging nets and fishing gears. Presence of the species results in economic losses at fish farms (intense clogging of nets).
Environmental ImpactTop of page Impact on Habitat
Impact on Biodiversity
Social ImpactTop of page
Risk and Impact FactorsTop of page Invasiveness
- Proved invasive outside its native range
- Has a broad native range
- Abundant in its native range
- Highly adaptable to different environments
- Is a habitat generalist
- Tolerates, or benefits from, cultivation, browsing pressure, mutilation, fire etc
- Fast growing
- Has high reproductive potential
- Has propagules that can remain viable for more than one year
- Reproduces asexually
- Has high genetic variability
- Altered trophic level
- Damaged ecosystem services
- Ecosystem change/ habitat alteration
- Modification of nutrient regime
- Modification of successional patterns
- Negatively impacts cultural/traditional practices
- Negatively impacts human health
- Negatively impacts aquaculture/fisheries
- Reduced native biodiversity
- Antagonistic (micro-organisms)
- Causes allergic responses
- Interaction with other invasive species
- Rapid growth
- Highly likely to be transported internationally accidentally
- Difficult to identify/detect as a commodity contaminant
- Difficult to identify/detect in the field
- Difficult/costly to control
Similarities to Other Species/ConditionsTop of page
C. pengoi may be confused with the Eurasian spiny water flea, Bythotrephes cederstroemii. Cercopagis is distinguished from Bythotrephes by the presence of the loop on the caudal process whereas Bythotrephes does not have such a loop.
Prevention and ControlTop of page Prevention
Monitoring and Surveillance
Gaps in Knowledge/Research NeedsTop of page
There is little experimental data on growth, production, feeding and ecosystem effects of C. pengoi. The paucity of ecological studies on C. pengoi is in part due to the difficulty in handling the species in experiments.
ReferencesTop of page
Benoit HP; Johannsson OE; Warner DM; Sprules WG; Rudstam LG, 2002. Assessing the impact of a recent predatory invader: The population dynamics, vertical distribution, and potential prey of Cercopagis pengoi in Lake Ontario. Limnology and Oceanography, 47:626-635.
Bielecka L; Mudrak S, 2010. New data on the non-indigenous cladoceran Cercopagis pengoi (Ostroumov 1891) in the Gulf of Gdansk (Baltic Sea). Oceanologia, 52(1):147-151. http://www.iopan.gda.pl/oceanologia/521biele.pdf
Bushnoe TM; Warner DM; Rudstam LG; Mills EL, 2003. Cercopagis pengoi as a new prey item for alewife (Alosa pseudoharengus) and rainbow smelt (Osmerus mordax) in Lake Ontario. Journal of Great Lakes Research, 29:205-212.
Bychenkov DE; Rodionova RV, 1996. Some results of the observations on the crustacean and rotifer plankton of the Neva Bay and the Gulf of Finland. Problems of Hydrobiology of Continental Waters and Their Malakofauna. Abstracts. St Petersburg, Russia: Zoological Institute RAS, 13-14.
Gorokhova E; Aladin N; Dumont HJ, 2000. Further expansion of the genus Cercopagis (Crustacea, Branchiopoda, Onychopoda) in the Baltic sea, with notes on the taxa present and their ecology. Hydrobiologia, 429(1/3):207-218.
Guher H, 2004. A study on morphological characters, spatial, and seasonal densitites, and co-existence of two predatory cladocera, Cercopagis pengoi (Ostroumov, 1891) and Cornigerius meaticus (Pengo, 1879) in Lake Terkos, Turkey. Crustaceana, 77(6):669-681.
Kane DD; Haas EM; Culver DA, 2003. The characteristics and potential ecological effects of the exotic crustacean zooplankter Cercopagis pengoi (Cladocera: Cercopagidae), a recent invader of Lake Erie. Ohio Journal of Science, 103(4):79-83.
Kotta J; Kotta I; Simm M; Lankov A; Lauringson V; Põllumäe A; Ojaveer H, 2006. Ecological consequences of biological invasions: three invertebrate case studies in the north-eastern Baltic Sea. Helgoland Marine Research, 60(2):106-112. http://www.springerlink.com/(vbc5i445bmwdkp45y4ynpj45)/app/home/contribution.asp?referrer=parent&backto=issue,6,13;journal,2,169;linkingpublicationresults,1:103796,1
Krylov PI; Bychenkov DE; Panov VE; Rodionova NV; Telesh IV, 1999. Distribution and seasonal dynamics of the Ponto-Caspian invader Cercopagis pengoi (Crustacea, Cladocera) in the Neva Estuary (Gulf of Finland). Hydrobiologia, 393:227-232.
Laxson CL; Mcphedran KN; Makarewicz JC; Telesh IV; MacIssac HJ, 2003. Effects of the non-indigenous cladoceran Cercopagis pengoi on the lower food web of Lake Ontario. Freshwater Biology, 48:2094-2106.
MacIsaac HJ; Grigorovich IA; Hoyle JA; Yan ND; Panov V, 1999. Invasion of Lake Ontario by the Ponto-Caspian predatory cladoceran Cercopagis pengoi. Canadian Journal of Fisheries and Aquatic Science, 56:1-5.
Makarewicz JC; Grigorovich IA; Mills E; Damaske E; Cristescu ME; Pearsall W; LaVoie MJ; Keats R; Rudstam L; Hebert P; Halbritter H; Kelly T; Matkovich C; MacIsaac HJ, 2001. Distribution, fecundity, and genetics of Cercopagis pengoi (Ostroumov) (Crustacea, Cladocera) in Lake Ontario. Journal of Great Lakes Research, 27(1):19-32.
New York Sea Grant, 2004. Guidelines for reducing the spread of 'fishhook waterfleas' (Cercopagis pengoi). Fact sheet. New York Sea Grant Communications [ed. by MacNeill D, Snyder M, Schultz K, Makarevicz J]. Stony Brook, USA: Stony Brook University.
Rivier IK, 1998. The predatory Cladocera (Onychopoda: Podonidae, Polyphemidae, Cercopagidae) and Leptodorida of the World. In: Guides to the identification of the micro-invertebrates of the continental waters of the world [ed. by Dumont HJF] Leiden, Netherlands: Backhuys Publishing, 13.
Strake S, 2002. The contribution of nonindigenous Cercopagis pengoi (Ostroumov) in the mesozooplankton community and its population structure in the Gulf of Riga. Proceedings of the Estonian Academy of Sciences Biology Ecology, 51:91-102.
Therriault TW; Grigorovich IA; Kane DD; Haas EM; Culver DA; MacIsaac HJ, 2002. Range expansion of the exotic zooplankter Cercopagis pengoi (Ostroumov, 1891) into western Lake Erie and Muskegon Lake. Journal of Great Lakes Research, 28:698-701.
Vanderploeg HA; Nalepa TF; Jude DJ; Mills EL; Holeck KT; Liebig JR; Grigorovich IA; Ojaveer H, 2002. Dispersal and emerging ecological impacts of Ponto-Caspian species in the Laurentian Great Lakes. Canadian Journal of Fisheries and Aquatic Sciences, 59:1209-1228.
ContributorsTop of page
10/12/07 Original text by:
Jonne Kotta, Estonian Marine Institute, University of Tartu, M Mäealuse 10a, Tallinn 12618, Estonia
Distribution MapsTop of page
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