Invasion History

First Non-native North American Tidal Record: 2011
First Non-native West Coast Tidal Record:
First Non-native East/Gulf Coast Tidal Record: 2011

General Invasion History:

Palaemon adspersus has a wide native distribution in the Northeast Atlantic, from southern Norway and southwest Finland (Baltic Sea) to the Mediterranean and Black Seas, the south coast of Morocco, and the Canary Islands (Holthuis 1980; Katajisto et al. 2013; U.S. National Museum of Natural History 2014). It is characteristic of brackish water and rare in exposed open-sea environments (Holthuis 1980; Berglund 1985). It was introduced as fish forage to the Caspian and Aral Seas (Zenkevitch 1963). In 2011, it was discovered in the Gulf of St. Lawrence, Newfoundland and the Magdalen Islands, Quebec where it was probably introduced by ballast water. Owing to its similarity with three native Palaemon species (formerly Palaemonetes) and two other introduced Palaemon (P. elegans and P. macrodactylus) this shrimp could be overlooked in other East Coast estuaries (González-Ortegón et al. 2015).

North American Invasion History:

Invasion History on the East Coast:

In 2011, specimens of Palaemon adspersus were collected at Stephen's Crossing, Newfoundland, and in the Magdalen Islands, Quebec. The identification was confirmed by molecular comparisons with European specimens. In 2012 - 2013, this shrimp was found at three other sites on the west coast of Newfoundland. Ballast water of ships from Europe is the most likely vector for the transport of these animals. Further surveys of Palaemon spp. (González-Ortegón et al. 2015) in East Coast waters are needed to determine whether P. adspersus is found in any other estuaries.

Invasion History Elsewhere in the World:

In 1934-1937, Palaemon adspersus and P. elegans, were stocked in the Caspian Sea as forage for commercial fishes. Both species are established and abundant in the Caspian Sea (Zenkevitch 1963; Aladin et al. 2002; Grigorovich et al. 2003). In 1954-1956, both species were transferred to the Aral Sea (Zenekvitch 1963). Through time, the Aral Sea has dried and shrunk. Palaemon elegans was still established in 2006, but P. adspersus was not reported (Aladin et al. 2008) and may be extinct.


Palaemon adspersus is a caridean shrimp characteristic of brackish water. It has a distinct, well-developed rostrum, with 5-7 dorsal teeth (one dorsal tooth lying posteriorly to the orbit), and usually three (sometimes two or four) ventral teeth. The rostrum has a weak ventral expansion. The carapace bears antennal and branchiostegal spines. The antennules are triramous. The shorter ramus of the outer antennule exceeds the length of its peduncle and is fused for about 1/3 of its length to the longer flagellum. Both legs of the first pair are chelate (with claws). The palp of the mandible has three segments. Adult shrimp are up to 80 mm long. The overall color is yellowish-gray, but the ventral side of the rostrum is marked with dark red spots. The long flagella and the peduncle of the antennules are also red. Description from: Holthuis 1980, Hayward and Ryland 1990, Ashelby et al. 2004, d'Udekem d'Acoz et al. 2005, González-Ortegón and Cuesta 2006, and González-Ortegón et al. 2015.

Larval development of several Northeast Atlantic Palaemon, including P. elegans, is described, with a key, in Fincham and Figueras (1986).


Taxonomic Tree

Kingdom:   Animalia
Phylum:   Arthropoda
Subphylum:   Crustacea
Class:   Malacostraca
Subclass:   Eumalacostraca
Superorder:   Eucarida
Order:   Decapoda
Suborder:   Pleocyemata
Infraorder:   Caridea
Family:   Palaemonidae
Genus:   Palaemon
Species:   adspersus


Cancer squilla (Linnaeus, 1758)
Palaemon communis (Anslijn, 1826)
Palaemon fabricii (Rathke, 1843)
Palaemon rectirostris (Zaddach, 1844)
Palaemon leachii (Bell, 1851)
Palaemon imbellis (Fischer, 1872)
Palaemon rectirostris octodentatus (Neumann, 1878)
Leander rectirostris typica (Czerniavsky, 1884)
Leander brandti (Czerniavsky, 1884)
Palaemon (Leander) brandti (Thallwitz, 1892)
Leander adspersus (Ortmann, 1894)
Leander adspersus fabricii (De Man, 1915)
Leander rectirostris octodentatus (Bolivar, 1916)
Leander imbellis (Kent, 1925)

Potentially Misidentified Species

Palaemon elegans
Rockpool Shrimp, native to East Atlantic, introduced to East Coast

Palaemon macrodactylus
Oriental Prawn, NW Pacific native, introduced to East and West coasts of North America

Palaemon mundusnovus
= Palaemonetes intermedius, NW Atlantic native (de Grave and Ashelby 2013; González-Ortegón 2015)

Palaemon pugio
= Palaemonetes pugio, NW Atlantic native (de Grave and Ashelby 2013; González-Ortegón et al. 2015)

Palaemon vulgaris
= Palaemonetes vulgaris, NW Atlantic native (de Grave and Ashelby 2013; González-Ortegón et al. 2015)



Life History- During reproduction in caridean shrimps, the copulating pair is usually oriented at right angles to one another, with the genital regions opposing each other. The modified first and second pairs of pleopods are used to transfer a spermatophore to a receptacle between the thoracic legs of the female (Barnes 1983). After mating, female palaemonid shrimps carry broods of fertilized eggs on their abdomen. Populations in the Adriatic and Black Sea had a range of 1000-2200 eggs per individual (Bilgin et al. 2009; Glamuzina et al. 2014). These hatch into planktonic larvae with feathery appendages, called zoeae. Shrimp zoeae lack the prominent spines seen in brachyuran crabs, and look shrimplike (Johnson and Allen 2005; Fincham and Figueras 1986). They go through several molts and metamorphose into postlarvae, which have well-developed walking legs and pleopods (swimmerets). After a subsequent molt, the body takes on the adult shape. Juveniles mature at about 1 year of age when they are 27-30 mm in size. Females tend to be larger than males, reaching 60-80 mm length vs. 60-62 mm for males. Lifespan is estimated at about 2.5- 3 years (Bilgin et al. 2009; Glamuzina et al. 2014).

Ecology- Palaemon aspersus inhabits shallow sandy areas in algal and eelgrass beds, often in brackish water (Holthuis 1980; Berglund 1985; González-Ortegón, et al. 2015). Individuals from the Baltic tolerate salinities as low as 1 PSU at 12 and 22°C, with little to no mortality. At 2°C, animals survived for at least 7 days at 7 PSU, but not at 1 or 5 PSU. Adult shrimps in colder regions may migrate into deeper water in winter, because of a reduced ability to regulate body fluids at low temperatures (Janas et al. 2013). A stable isotope study in the Baltic Sea population showed that P. elegans fed on animal prey, primarily Crustacea (70%) and green algae (10%). Most of the animal prey appeared to be benthic crustaceans. Mysids were readily eaten in experiments (Guerao 1994).


Amphipods, mollusks, plant material


fishes, humans


Other shrimps

Trophic Status:




General HabitatGrass BedNone
General HabitatUnstructured BottomNone
General HabitatSalt-brackish marshNone
Salinity RangeOligohaline0.5-5 PSU
Salinity RangeMesohaline5-18 PSU
Salinity RangePolyhaline18-30 PSU
Salinity RangeEuhaline30-40 PSU
Tidal RangeSubtidalNone
Vertical HabitatEpibenthicNone
Vertical HabitatNektonicNone

Tolerances and Life History Parameters

Minimum Temperature (ºC)0Janas et al.2013
Maximum Temperature (ºC)26.5Glamuzina et al. 2014 (field, Croatia). However, in the Gullmar Fjord, Sweden, this shrimp migrates to deeper waters at temperatures above 19 C (Berglund 1980).
Minimum Salinity (‰)1Janas et al. 2013
Maximum Salinity (‰)38Typical salinity, Mediterranean Sea
Minimum Reproductive Temperature10Field, Turkey, Black Sea (Bilgin et al. 2009)
Maximum Reproductive Temperature26Croatia, Adriatic Sea (Glamuzina et al. 2014)
Minimum Reproductive Salinity5Experimental (Sweden, Berglund 1985)
Maximum Reproductive Salinity35Field (González-Ortegón et al. 2015), but not tested at salinities above 25 PSU (Berglund 1985)
Maximum Duration24Experimental. MAKAROV YU N; GOLODETSKII L A 1980. LARVAL DEVELOPMENT OF THE BLACK SEA PRAWN PALAEMON-ADSPERSUS CRUSTACEA DECAPODA IN THE LABORATORY. Zoologicheskii Zhurnal Volume: 59 Issue: 3 Pages: 375-382 Published: 1980
Minimum Length (mm)27Matue males, Croatia, Turkey (Bilgin et al. 2009; Glamuzina et al. 2014); 30mm for females with eggs, Croatia (Glamuzina et al. 2014); 38 mm, Turkey, Black Sea (Bilger et al. 2009).
Maximum Length (mm)80Holthuis 1980; Bilgin et al. 2009
Broad Temperature RangeNoneCold temperate-Warm temperate
Broad Salinity RangeNoneOligohaline-Euhaline

General Impacts

Palaemon adspersus supports small, localized fisheries in Europe (Holthuis 1980). In the Caspian Sea, P. adspersus was introduced as a forage item for fishes (Zenkevitch 1963). No impacts are known in the Gulf of St. Lawrence, Canada where this shrimp was only recently discovered (Gonzalez-Ortegon et al. 2015).

Regional Distribution Map

Bioregion Region Name Year Invasion Status Population Status
NA-S3 None 2011 Def Estab
NEA-II None 0 Native Estab
B-I None 0 Native Estab
NEA-IV None 0 Native Estab
NEA-V None 0 Native Estab
MED-II None 0 Native Estab
WA-I None 0 Native Estab
MED-III None 0 Native Estab
MED-VIII None 0 Native Estab
B-VII None 0 Native Estab
MED-IX None 0 Native Estab
B-X None 0 Native Estab
MED-VII None 0 Native Estab
MED-IV None 0 Native Estab
MED-VI None 0 Native Estab
CASP Caspian Sea 1937 Def Estab
MED-V None 0 Native Estab
B-III None 0 Native Estab
ARAL Aral Sea 1956 Def Unk
B-IV None 0 Native Estab
B-VI None 0 Native Estab
B-II None 0 Prb Estab
MED-I None 0 Native Estab
AR-V None 0 Native Estab

Occurrence Map

OCC_ID Author Year Date Locality Status Latitude Longitude


Aladin, N. ; Plotnikov, I.; Ballatore, T.; Micklin, P. (2008) Japan International Cooperation Agency: Study Reports: Country and Regional Study Reports: Central Asia and Caucasus. Vol. 4., Japan International Cooperation Agency, <missing place>. Pp. 4-12

Aladin, Nikolai V.; Plotnikov, Igor S.; Filipov, Andrei A. (2002) Invasive aquatic species of Europe: Distribution, impacts, and management., Kluwer Academic Publishers, Dordrecht. Pp. 351-359

Ashelby, Christopher W.; Worsfold, Tim M.; Fransen, Charles H. J. M. (2004) First records of the Oriental prawn Palaemon macrodactylus (Decapoda: Caridea), an alien species in European waters, with a revised key to British Palaemonidae., Journal of the Marine Biological Association of the United Kingdom 84: 1041-1050

Barnes, Robert D. (1983) Invertebrate Zoology, Saunders, Philadelphia. Pp. 883

Berglund, Anders (1980) Niche differentiation between two littoral prawns in Gullmar Fjord, Sweden: Palaemon adspersus and P. squilla, Holarctic Ecology 3: 111-115

Berglund, Anders (1984) Reproductive adaptations in two Palaemon prawn species with differing habitat requirements, Marine Ecology Progress Series 17: 77-83

Berglund, Anders (1985a) Different reproductive success at low salinity determines the estuarine distribution of two Palaemon prawn species, Holarctic Ecology 8(1): 49-52

Bilgin, Sabri; Samsun, Osman; Ozen, Ozcan (2009) Seasonal growth and reproduction biology of the Baltic prawn, Palaemon adspersus (Decapoda: Palaemonidae), in the southern Black Sea, Journal of the Marine Biological Association of the United Kingdom 89(3): 509-519

Cavraro, Francesco; Zucchetta, Matteo; Franzoi, Piero (2014) First record of adult specimens of the Oriental shrimp Palaemon macrodactylus Rathbun, 1902 in the Venice Lagoon (north Adriatic Sea, Italy), BioInvasions Records 3(4): 261-267

d'Udekem d'Acoz, Cédric; Faasse, Marco;Dumoulin, Emmanuel; De Blauwe, Hans (2005) Occurrence of the Asian shrimp Palaemon macrodactylus in the southern bight of the North Sea, with a key to the Palaemonidae of north-western Europe (Crustacea: Decapoda: Caridea), Nederlandse Faunistiche Mededelingen 22: 94-111

de Grave, Sammy; Ashelby, Christopher W. (2013) A re-appraisal of the systematic status of selected genera in Palaemoninae (Crustacea: Decapoda: Palaemonidae), Zootaxa 3734(3): 331-344

Fincham, A. A.; Figueras, A. J. (1986) Larval keys and diagnoses for the subfamily Palaemoninae (Crustacea: Decapoda: Palaemonidae) in the north-east Atlantic and aspects of functional morphology, Journal of Natural History 20(1): 203-224

Glamuzina, L. and 6 authors (2014) Population structure, growth, mortality and fecundity of Palaemon adspersus (Rathke 1837; Decapoda: Palaemonidae) in the Parila Lagoon (Croatia, SE Adriatic Sea) with notes on the population management, Turkish Journal of Fisheries and Aquatic Sciences 14: 677-687

Gonzalez-Ortegon, Enrique; Cuesta, Jose A. (2006) An illustrated key to species of Palaemon and Palaemonetes (Crustacea: Decapoda: Caridea) from European waters, including the alien species Palaemon macrodactylus, Journal of the Marine Biological Association of the United Kingdom 86: 93-102

González-Ortegón, Enrique; Sargent, Philip; Pohle, Gerhard; Martinez-Lage, Andres (2015) The Baltic prawn Palaemon adspersus Rathke, 1837 (Decapoda, Caridea, Palaemonidae): first record, possible establishment, and illustrated key of the subfamily Palaemoninae in northwest Atlantic waters, Aquatic Invasions 10(3): 275-285

Grabowski, Michal (2006) Rapid colonization of the Polish Baltic coast by an Atlantic palaemonid shrimp Palaemon elegans Rathke, 1837, Aquatic Invasions 1(3): 116-123

Grigorovich, Igor A.; Therriault, Thomas W.; MacIsaac, Hugh J. (2003) History of aquatic invertebrate invasions in the Caspian Sea., Biological Invasions 5: 103-115

Guerao, G. (1993-1994) Feeding habits of the prawns Processa edulis and Palaemon adspersus (Crustacea: Decapoda: Caridea) in the Alfacs Bay, Ebro Delta, Mediterranean Sea, Miscellanea Zoologica 117: 115-122

Hagerman, L.; Ostrup, J. (1980) Seasonal and diel activity variations in the shrimp Palaemon adspersus from a brackish, non-tidal area, Marine Ecology Progress Series 2: 29-335

Hayward, P.J.; Ryland, J. S. (1990) The Marine Fauna of the British Isles and North-West Europe, 1 Clarendon Press, Oxford. Pp. <missing location>

Holthuis, L. B. (1961) Report on a collection of Crustacea Decapoda and Stomatopoda from Turkey and the Balkans, Zoologische Verhandelingen 47: 1-67

Holthuis, L. B. (1980) FAO Species Catalogue: Vol. 1. Shrimps and Prawns of the World., Food and Agricultural Organization, Rome. Pp. <missing location>

Janas, Urzula; Pilka, Malgorzata; Lipinska, Dagmara (2013) Temperature and salinity requirements of Palaemon adspersus Rathke, 1837 and Palaemon elegans Rathke, 1837. Do they explain the occurrence and expansion of prawns in the Baltic Sea?, Marine Biology Research 9(3): 293-300

Johnson, William S.; Allen, Dennis M. (2005) <missing title>, Johns Hopkins Press, Baltimore. Pp. <missing location>

Katajisto, Tarja; Kotta, Jonne; Lehtiniemi, Maiju; Malavin, Stanislaw A.; Panov, Vadim E. (2013) Palaemon elegans Rathke, 1837 (Caridea: Palaemonoidea: Palaemonidae) established in the Gulf of Finland, Bioinvasion Records 2: in press

Luiz, Osmar J. and 7 authors (2021) Multiple lionfish (Pterois spp.) new occurrences along the Brazilian coast confirm the invasion pathway nto the Southwestern Atlantic, Biological Invasions 23: 3013-3019

Manent, Pablo; Abella-Gutiérrez, Jose (2006) Population biology of Palaemon adspersus Rathke, 1837 (Decapoda, Caridea) in Fornells Bay, Balearic Islands, Western Mediterranean, Crustaceana 79(11): 1297-1308

Micu, Dragos; Nita, Victor (2009) First record of the Asian prawn Palaemon macrodactylus Rathbun, 1902 (Caridea: Palaemonoidea: Palaemonidae) from the Black Sea, Aquatic Invasions 4(4): <missing location>

Museum of Comparative Zoology 2008-2015 Invertebrate Zoology Collections Database <missing URL>

Ruiz, Gregory M.; Geller, Jonathan (2018) Spatial and temporal analysis of marine invasions in California, Part II: Humboldt Bay, Marina del Re, Port Hueneme, and San Francisco Bay, Smithsonian Environmental Research Center & Moss Landing Laboratories, Edgewater MD, Moss Landing CA. Pp. <missing location>

U.S. National Museum of Natural History 2002-2021 Invertebrate Zoology Collections Database.

Zaitsev, Yuvenali; Ozturk, Bayram (2001) <missing title>, Turkish Marine Research Foundation Publication, <missing place>. Pp. 1-265

Zenkevitch, L. (1963) <missing title>, Allen & Unwin, London. Pp. <missing location>