Invasion History

First Non-native North American Tidal Record: 1864
First Non-native West Coast Tidal Record:
First Non-native East/Gulf Coast Tidal Record: 1864

General Invasion History:

Orchestia gammarellus has a wide native distribution in the Northeast Atlantic, from southern Norway to the Mediterranean and Black Seas, as well as the Azores. Madeira, and the Canary Islands (Dahl 1967; Lincoln 1979; Bellan-Santini et al. 1993; Sezgun et al. 2001). It has a much narrower range in the Northwest Atlantic, from northern Newfoundland to Casco Bay, Maine (Bousfield 1973), and is thought to be introduced here (Chapman 2000). Patterns of genetic diversity and abundance are consistent with a spread from east to west (Norway, Scotland, and Baltic to Iceland and North America) (Henzler and Ingolfsson 2008). Introduced populations are also known from South Africa, Argentina, and Chile (Orensanz et al. 2002; Lopez Gappa et al. 2006; Mead et al. 2011b; Pérez-Schultheiss 2014). Likely vectors for transport are dry ballast and cargo, given the littoral habitat and air-breathing nature of these amphipods.

North American Invasion History:

Invasion History on the East Coast:

The timing of the introduction of Orchestia gammarellus to Northeastern North America is not known, but one museum specimen was collected in Passamaquoddy Bay, Maine in 1864 (Yale Peabody Museum of Natural History 2016). Bousfield (1973) gave the range as: 'from eastern and southern Newfoundland to Cape Breton Island; from the western end of Nova Scotia and throughout Bay of Fundy along coast of Maine to Casco Bay.' Steele (1961) reported one record each from the western shore (Port au Port) and the northern shore (Notre Dame Bay) of Newfoundland. Henzler and Ingolfsson (2008) commented on the scarcity and patchy distribution of this amphipod in Atlantic Canada, in contrast to its abundance in Europe.

Invasion History Elsewhere in the World:

Orchestia gammarellus was first collected in Iceland in 1968, near Reykjavik. In southwest Iceland, it occurs along the coast from Reykjavík to Strandarkirkjar. In northwest Iceland, during 2000-2002, it was found at 12 sites from Gjorvidalur to Skaro, but with a very limited distribution in intertidal hot springs (Henzler and Ingolfsson 2008). In South Africa, O. gammarellus was collected in 1949 at Langebaan, north of Cape Town, and at the Knysna Estuary, on the southern coast. It was found near Table Bay, Cape Town, in 2008 (Mead et al. 2011b). On the other side of the Atlantic, this amphipod was collected in Rio Negro Province, Argentina before 1978, and later found near Puerto Deseado, Santa Cruz in 1986 (Orensanz et al. 2002). In Chile, it has been found at three widely separated sites, Playa Changa, Coquimbo at 30°S in 2005; Concón, Reg. de Valparaíso at 36°S in 2005; and Puerto Montt at 41.5°S in 2013 (Pérez-Schultheiss 2014). The pattern of invasion at many of these locations seems very patchy, possibly reflecting this amphipod's poor ability to disperse by rafting (Henzler and Ingolfsson 2008), making it dependent on many independent local transport events on ships, small boats, fishing gear, bait wrapped in seaweed, etc.


Orchestia gammarellus is an amphipod of the family Talitridae. General features of this family include a laterally compressed, arched body; a short Antenna 1 and long Antenna 2; well-developed eyes and pereiopods (walking legs); hopping locomotion; and the ability to survive exposure to air in beach wrack-lines and debris. Orchestia gammarellus has a squarish-oval, medium-sized eye. Antenna 1 is short, with its tip reaching the distal end of peduncle segment 2 of Antenna 2. The peduncle of Antenna 1 has 4 segments, and the flagellum has 4-5 segments. Antenna 2 is about 1/3 body-length. The peduncle is more robust in the male than female, and the flagellum is slightly shorter than the peduncle. In both sexes, Gnathopod 1 is much smaller than Gnathopod 2. The dactyl (segment 7) of Gnathopod 1 barely overlaps the palm. The propodus of Gnathopod 2 is greatly inflated, especially in the male. The dactylus is shorter than the palm. Pereiopods 3 and 4 are relatively short. Perieopods 5-7 are progressively longer, and their coxal plates larger. The abdominal side plates 2 and 3 have angular corners. The urosome segments are distinct. Uropods 1 and 2 are biramous, while Uropod 3 is uniramous, with the distal segment blunt and spine-like. The telson is spade-like, formed of two medially fused lobes with stout lateral and apical spines. Adult males reach 16-18 mm, while females reach 14 mm. The color ranges from greenish brown to reddish brown. This description is based on: Bousfield 1973 and Lincoln 1979.


Taxonomic Tree

Kingdom:   Animalia
Phylum:   Arthropoda
Subphylum:   Crustacea
Class:   Malacostraca
Subclass:   Eumalacostraca
Superorder:   Peracarida
Order:   Amphipoda
Suborder:   Gammaridea
Family:   Talitridae
Genus:   Orchestia
Species:   gammarellus


Onicus gammarellus (Pallas, 1776)
Cancer gammarellus (J. F.W. Herbst, 1793)
Gammarus gammarellus (A.G. Olivier, 1791)
Porrassia mallorquensis (Marcus, 1912)
Orchestia gammarella (None, None)
Talorchestia inaequalipes (Barnard, 1951)

Potentially Misidentified Species

Orchestia grillus
Northwest Atlantic, Gulf of St. Lawrence to Gulf of Mexico (Bousfield 1973)

Orchestia uhleri
Northwest Atlantic, Casco Bay to Gulf of Mexico (Bousfield 1973)

Platorchestia platensis
Type species of a nearly cosmopolitan species complex, Gulf of St. Lawrence to Patagonia, range expansion in North Sea and Baltic, North Sea to South Africa (Bousfield 1973; Persson 2001; Spicer and Janas 2006). Populations in Japan, Australia, and Ascension Island-St. Helena have been described as separate species.



In European waters, Orchestia gammarellus cannot survive prolonged immersion, but is tolerant of rain and sharp changes in salinity. Sexes are separate, the young are brooded, and development is direct. In New England and the Maritime Provinces, populations are annual, females are ovigerous from May through August, and have more than one brood per year (Bousfield 1973). Females in Morocco have a mean brood size of 15 eggs per female, and 4-5 broods per year, but only a 10-month life-span (Aksissou and Elkaim 1996). Females on the Swedish Baltic shores had 5-30 eggs, increasing with body size (Persson et al. 1999).

In the Northeast Atlantic, O. gammarellus ranges from cold-temperate zones (southern Norway, Faroe Islands) to subtropical regions (Morocco, Tunisia, Madeira, Canary Islands) and survives a wide range of temperature, from below freezing to 38°C (Dahl 1967; Aksissou and Elkaim 1994; Persson 1999; Morritt and Ingolfsson 2000; Henzler and Ingolfsson 2008). As an inhabitant of the upper shore, exposed to rainfall and evaporation, O. gammarellus tolerates a wide range of salinity (3.5-51 PSU), but has not colonized freshwater regions or the lowest salinity regions of estuaries (Persson 1999). Orchestia gammarellus appears to have a wider habitat range in its native habitat in the Northeast Atlantic, including rocky shores, salt marshes, sand-dunes, banks of freshwater streams, and springs on cliffs high above the sea (Dahl 1967; Persson 1999; Dias and Sprung 2004; Colombini et al. 2013). While in the Northwest Atlantic, it is found mostly on rocky and gravelly shores, and occasionally in marshes and estuaries (Bousfield 1973).

Orchestia gammarellus is a littoral scavenger, but primarily herbivorous, feeding on washed-up wrack and detritus. It is usually considered to prefer algal wrack, and cannot digest Eelgrass (Zostera marina), but does feed on attached microorganisms. Population characteristics did not differ between populations in algal and seagrass wrack (Persson 1999).


stranded seaweed, seagrasses


Shorebirds, insects


Platorchestia platensis

Trophic Status:




General HabitatUnstructured BottomNone
General HabitatSalt-brackish marshNone
General HabitatCoarse Woody DebrisNone
General HabitatRockyNone
Salinity RangeMesohaline5-18 PSU
Salinity RangePolyhaline18-30 PSU
Salinity RangeHyperhaline40+ PSU
Tidal RangeHigh IntertidalNone
Tidal RangeSupratidalNone
Vertical HabitatEpibenthicNone

Tolerances and Life History Parameters

Minimum Temperature (ºC)0Hibernates buried in sand and wrack.
Maximum Temperature (ºC)37Experimental, CTM (Critical temperature maxima) of 38 C for animals acclimated at 22 C (Morritt and Ingolfsson 2000) Tempreature tolerances for O. gammarellus in two populations, from Scotland and England, had upper thermal tolerances varying from 29.5 to 39.5 C, depending on geographical origin, and acclimation (5 and 25 C) (Gaston and Spicer 1998)/
Minimum Salinity (‰)3.5Morritt and Stevenson 1993, cited by Persson 2001
Maximum Salinity (‰)51Experimental, Persson 2001
Minimum Reproductive Temperature10Field, air temperature, Europe (Persson 1999).
Minimum Reproductive Salinity3.5Morritt and Stevenson 1993, cited by Persson 2001
Maximum Length (mm)16Males reach 16 mm, females 14 mm (Bousfield 1973)

General Impacts

No impacts have been reported for introduced populations of Orchestia gammarellus.

Regional Distribution Map

Bioregion Region Name Year Invasion Status Population Status
NA-ET2 Bay of Fundy to Cape Cod 1864 Def Estab
NEA-III None 0 Native Estab
N010 Passamaquoddy Bay 1864 Def Estab
N100 Casco Bay 1973 Def Estab
NA-ET1 Gulf of St. Lawrence to Bay of Fundy 1973 Def Estab
NA-S3 None 1961 Def Estab
NA-S2 None 1961 Def Estab
NEA-IV None 0 Native Estab
NEA-II None 0 Native Estab
AR-IV None 1968 Def Estab
AR-V None 0 Native Estab
B-VI None 0 Native Estab
MED-III None 0 Native Estab
MED-VI None 0 Native Estab
MED-VIII None 0 Native Estab
NEA-V None 0 Native Estab
MED-I None 0 Native Estab
MED-IX None 0 Native Estab
B-I None 0 Native Estab
B-IV None 0 Native Estab
B-V None 0 Native Estab
WA-IV None 1949 Def Estab
WA-V None 1949 Def Estab
SA-I None 1978 Def Estab
NEA-VI None 0 Native Estab
MED-II None 0 Native Estab
MED-IV None 0 Native Estab
MED-VII None 0 Native Estab
MED-V None 0 Native Estab
SEP-C None 2005 Def Estab
SEP-A' None 2013 Def Estab
WA-I None 0 Native Estab

Occurrence Map

OCC_ID Author Year Date Locality Status Latitude Longitude


Aksissou, M.; Elkaím, B. (1996) [Reproductive cycle of a population of Orchestia gammarellus (Crustacea, Amphipoda) in Lake Smir (Motocco], Mediterranea 1996: 5-11

Appeltans, W. et al. 2011-2015 World Registry of Marine Species. <missing URL>

Ayari, Amel; Bohli, Dhouha; Nasri-Ammar, Karima (2011) Population dynamics and structure of talitrid amphipods from Bizerte sandy beach (North of Tunisia), Travaux de l Institut Scientifique, Rabat, série générale 6: 13-16

Bellan-Santini, Denise; Karaman, Gordon; Krapp-Schickel, Gertraud; Ledoyer, Michel; Myers, Alan A.; Ruffo, Sandro; Schiecke, Ulrich (1993) The Amphipoda of the Mediterranean: Part 3. Gammaridea: Melphippidae to Talitridae; Ingolfiellidea; Caprellidea, Memoires de l'Institut Oceanographique (Monaco) 13: 577-813

Bousfield, E. L. (1958) Littoral marine arthropods and mollusks collected in western Nova Scotia, 1956, Proceedings of the Nova Scotian Institute of Science 24: 303-325

Bousfield, E.L. (1958) Freshwater amphipod crustaceans of glaciated North Amerca., Canadian Field-Naturalist 72(2): 55-113

Bousfield, E.L. (1973) <missing title>, Comstock Publishing Associates, Ithaca, NY. Pp. <missing location>

Camur-Elipek, B.; Aslan-Cihangir, H. (2007) First observations of two talitrid crustaceans (Amphipoda: Talitridae) from Gokceada island (NE Aegean Sea), Mediterranean Marine Science 8(2): 83-86

Chapman, John W. (2000) Marine Biological Invasions; Proceedings of the first national conference, January 24-27, 1999., MIT Sea Grant College Program, Cambridge MA. Pp. 66-80

Colombini, Isabella and 5 authors (2013) The behavioural ecology of two sympatric talitrid species, Talitrus saltator (Montagu) and Orchestia gammarellus (Pallas) on a Tyrrhenian sandy beach dune system, Estuarine, Coastal and Shelf Science 117: 37-47

Costa, Ana Christina (2010) A list of the terrestrial and marine biota from the Azores, Princípia Editora, Ponta Delgada, Azores, Portugal. Pp. 287-324

Dahl, Erik (1967) Land amphipods from the Azores and Madeira, Boletin do Museu Municipal do Funchal 21(96): 1-23

Dias, Natália; Sprung, Martin / and MARTIN SPRUNG (2004) Population dynamics and production of the amphipod Orchestia gammarellus (Talitridae) in a Ria Formosa saltmarsh (southern Portugal), Crustaceana 76: 1123-1141

Gaston, Kevin J.; Spicer, John I. (1998) Do upper thermal tolerances differ in geographically separated populations of the beachflea Orchestia gammarellus (Crustacea: Amphipoda)?, Journal of Experimental Marine Biology and Ecology 229: 265-276

Henzler, Christine M.; Ingólfsson, Agnar (2008) The biogeography of the beachflea, Orchestia gammarellus (Crustacea, Amphipoda, Talitridae), in the North Atlantic with special reference to Iceland: a morphometric and genetic study, Zoologica Scripta 37: 57-70

Ingolfsson, A.; Olafsson, O. P.; Morritt, D. (2007) Reproduction and life-cycle of the beachflea (Orchestia gammarellus (Pallas) (Crustacea: Amphipoda) at thermal and non-thermal sites in the intertidal of Iceland: how important is temperature?, Marine Biology 150: 1333-1343

Lincoln, Roger J. (1979) British Marine Amphipoda: Gammaridea., In: (Eds.) . , London. Pp. <missing location>

Mead, A.; Carlton, J. T.; Griffiths, C. L.; Rius, M. (2011a) Revealing the scale of marine bioinvasions in developing regions: a South African re-assessment, Biological Invasions 13(9): 1991-2008

Mead, A.; Carlton, J. T.; Griffiths, C. L. Rius, M. (2011b) Introduced and cryptogenic marine and estuarine species of South Africa, Journal of Natural History 39-40: 2463-2524

Morritt, David; Ingolfsson, Agnar (2000) Upper thermal tolerances of the beachflea Orchestia gammarellus (Pallas) (Crustacea: Amphipoda: Talitridae) associated with hot springs in Iceland, Journal of Experimental Marine Biology and Ecology 255: 215-227

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

Orensanz, Jose Maria and 14 other authors (2002) No longer the pristine confines of the world ocean: a survey of exotic marine species in the southwestern Atlantic, Biological Invasions 4(1-2): 115-143

Pérez-Schultheiss, Jorge (2014) First record of Orchestia gammarellus (Crustacea: Amphipoda: Talitroidea) in Chile, with comments on its morphologic variability, Boletin de Biodiversidad de Chile 9: 21-33

Persson, L.-E. (2001) Dispersal of Platorchestia platensis (Kroyer) (Amphipoda: Talitridae) along Swedish coasts: A slow but successful process, Estuarine, Coastal and Shelf Science 52: 201-210

Persson, Lars-Eric (1999) Growth and reproduction in two brackish water populations of Orchestia gammarellus (Amphipoda: Talitridae) in the Baltic Sea, Journal of Crustacean Biology 19(1): 53-59

Sezgin, M. Aydemir Çil, E. (2010) Rocky bottom crustacean fauna of Sinop (Black Sea, Turkey) coast, Zoologia Baetica 21: 5-14

Sezgün, Murat; Kocata, Ahmet; Kataúan, Tuncer (2001) Amphipod fauna of the Turkish central Black Sea region, Turkish Journal of Zoology 25: 57-61

Spicer, John I.; Janas, Urszula (2006) The beachflea Platorchestia platensis (Krøyer, 1845): a new addition to the Polish fauna (with a key to Baltic talitrid amphipods)*, Oceanologia 48: 287-295

Steele, Donald H. (1961) <missing title>, McGill University, Montreal, Quebec. Pp. 350 pp.

Trott, Thomas J. (2004) Cobscook Bay inventory: a historical checklist of marine invertebrates spanning 162 years., Northeastern Naturalist 11(Special issue 2): 261-324

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

White, K. L.; Townsend, S. M.; Reynolds, A. S. Barrington, E. B. (2010) Intertidal invertebrates of Scatarie Island: a preliminary species inventory and habitat description, Proceedings of the Nova Scotian Institute of Science 45(1): 9-17

Yale Peabody Museum of Natural History 2008-2016 YPM Invertebrate Zoology - Online Catalog. <missing URL>

Yip, Zhi Ting; Lim, Chin Sing; Tay, Ywee Chieh; Yong How Jonathan Tan4, Stephen Beng5, Tun, Karenne;; Teo; Serena Lay-Ming; Huang, Danwei (2021) Environmental DNA detection of the invasive mussel Mytella strigata as a surveillance tool, Management of Biological Invasions 12: Published onlinbe