Association with vessel vectors

Actual evidence of being found in samples in a particular vector from any world region.

Anchor and anchor chains. Organisms found on anchors, anchor chain or within attached sediments, including anchor chain lockers.

Ballast water. Ballast water means water with its suspended matter taken on board a ship to control trim, list, draught, stability or stresses of the ship.

Biofouling. Biofouling means the accumulation of aquatic organisms such as micro-organisms, plants, and animals on surfaces and structures immersed in or exposed to the aquatic environment. Biofouling can include microfouling and macrofouling.

  • Macrofouling means large, distinct multicellular organisms visible to the human eye such as barnacles, tubeworms, or fronds of algae.
  • Microfouling means microscopic organisms including bacteria and diatoms and the slimy substances that they produce.
Biofouling comprised of only microfouling is commonly referred to as a slime layer.

Sea chest. The sea chests are cavities (an opening with protection grid) at the bottom side of the ships’ hull (an opening for pumping in and out water for, e.g., ballasting, firefighting) where aquatic organisms may settle and be transported.

Tank sediments. Matter settled out of ballast water within a ship.

Bioaccumulation association

Natural toxins. An organism that accumulates toxins naturally produced by other organisms, such as phytotoxins, in its tissues.

Anthropogenic chemical compounds. An organism that accumulates human-produced chemicals, such as pharmaceuticals, heavy metals, pesticides, dioxins, in its tissues.

Characteristic feeding method

Chemoautotroph. An organism that obtains metabolic energy by oxidation of inorganic substrates such as sulphur, nitrogen or iron.

Deposit feeder – Subsurface. Synonym: detritivore. An organism feeding on fragmented particulate organic matter in the substratum.

Deposit feeder – Surface. Synonym: detritivore. An organism feeding on fragmented particulate organic matter from the surface of the substratum.

Grazer. An organism feeding on plants (higher aquatic plants, benthic algae and phytoplankton) and/or sessile animals organisms.

Herbivore. An organism feeding on plants (higher aquatic plants, benthic algae and phytoplankton).

Mixotroph. An organism both autotrophic and heterotrophic.

Omnivore. An organism feeding on mixed diet of plant and animal material.

Parasite. Feeding on the tissues, blood or other substances of a host.

Photoautotroph. An organism that obtains metabolic energy from light by photosynthesis (e.g. seaweeds, phytoplankton).

Planktotroph. An organism feeding on plankton.

Predator. An organism that feeds by preying on other organisms, killing them for food.

Scavenger. An organism feeding on dead and decaying organic material.

Suspension feeder – Active. An organism feeding on particulate organic matter, including plankton, suspended in the water column, collecting it actively by sweeping or pumping (creating feeding currents).

Suspension feeder – Passive. An organism feeding on particulate organic matter, including plankton, suspended in the water column, utilizing the natural flow to bring particles in contact with feeding structures.

Symbiont contribution. Where some dietary component(s) are provided by symbiotic organisms (e.g. Anemonia with zooxanthellae).

Developmental trait

Brooding. The incubation of eggs either inside or outside the body. Eggs may be brooded to a variety of developmental stages. Males or females may be responsible for brooding.

Direct development. A life cycle lacking a larval stage.

Spawning. The release of gametes into the water.

Lecithotrophy. Development at the expense of internal resources (i.e. yolk) provided by the female.

Parental care. Any form of parental behaviour that is likely to increase the fitness of offspring.

Planktotrophy. Feeding on plankton.

Resting stages. The quiescent stage in the life cycle (dormancy, diapause).

Viviparous. Producing live offspring from within parental body.

Habitat modifying ability potential

Autogenic ecosystem engineers. Organisms which change the environment via their own physical structures (i.e. their living and dead tissues) such as corals, oysters, kelps, sea grasses, etc.

Allogenic ecosystem engineers. Organisms which modify the environment by causing physical state changes in biotic and abiotic materials that, directly or indirectly, modulate the availability of resources to other species (e.g. excavating deep burrows which other organisms co-occupy, damming the water flow, etc).

Keystone species. A keystone species is crucial in maintaining the organization and diversity of its ecological community, by determining the types and numbers of other species.

Life form

Neuston. Organisms that live on (epineuston) or under (hyponeuston) the surface film of water bodies.

Zoobenthos. Animals living on or in the seabed.

Phytobenthos. Algae and higher plants living on or in the seabed.

Zooplankton. Animals living in the water column, unable to maintain their position independent of water movements.

Phytoplankton. Microscopic plankton algae and cyanobacteria.

Benthopelagos. Synonyms: hyperbenthic, benthopelagic, nektobenthic, demersal. An organism living at, in or near the bottom of the sea, but having the ability to swim.

Nekton. Actively swimming aquatic organisms able to move independently of water currents.

Parasite. An organism intimately associated with and metabolically dependent on another living organism (host) for completion of its life cycle.

Symbiont (nonparasitic). An organism living mutually with another species without harming it. Association of two species (symbionts) may be mutually beneficial.


Boring. An organism capable of penetrating a solid substrate by mechanical scraping or chemical dissolution.

Burrowing. An organism capable of digging in sediment.

Crawling. An organism moving slowly along on the substrate.

Drifting. An organism whose movement is dependent on wind or water currents.

Permanent attachment. Non-motile; permanently attached at the base. Also includes permanent attachment to a host.

Swimming. An organism capable of moving through the water by means of fins, limbs or appendages.

Temporary attachment. Temporary / sporadic attachment. Attached to a substratum but capable of movement across (or through) it (e.g. Actinia). Also includes temporary attachment to a host.

Native origin

The region the species originates from.


References should follow the standard of Biological invasions:

Journal article
Gamelin FX, Baquet G, Berthoin S, Thevenet D, Nourry C, Nottin S, Bosquet L (2009) Effect of high intensity intermittent training on heart rate variability in prepubescent children. Eur J Appl Physiol 105:731-738. doi: 10.1007/s00421-008-0955-8
Ideally, the names of all authors should be provided, but the usage of “et al” in long author lists will also be accepted:
Smith J, Jones M Jr, Houghton L et al (1999) Future of health insurance. N Engl J Med 965:325–329

Article by DOI

Slifka MK, Whitton JL (2000) Clinical implications of dysregulated cytokine production. J Mol Med. doi:10.1007/s001090000086

South J, Blass B (2001) The future of modern genomics. Blackwell, London

Book chapter
Brown B, Aaron M (2001) The politics of nature. In: Smith J (ed) The rise of modern genomics, 3rd edn. Wiley, New York, pp 230-257

Online document
Cartwright J (2007) Big stars have weather too. IOP Publishing PhysicsWeb. Accessed 26 June 2007

Trent JW (1975) Experimental acute renal failure. Dissertation, University of California

Reproductive frequency

Iteroparous. Organisms breeding more than once in their lifetime.

Semelparous. Organisms breeding once in their lifetime.

Reproductive type

Asexual. Budding, Fission, Fragmentaion, including parthenogenesis. A form of asexual multiplication in which:
a) a new individual begins life as an outgrowth from the body of the parent. It may then separate to lead an independent existence or remain connected or otherwise associated to form a colonial organism;
b) the ovum develops into a new individual without fertilization;
c) division of the body into two or more parts each or all of which can grow into new individuals is involved.

Self-fertilization. Selfing or autogamy. The union of a male and female gamete produced by the same individual.

Sexual. Permanent hermaphrodite, Protandrous hermaphrodite, Protogynous hermaphrodite, Gonochoristic.
Capable of producing both ova and spermatozoa either at the same time. A condition of hermaphroditism in plants and animals where male gametes mature and are shed before female gametes mature or vice versa.
Having separate sexes.


The exact salinity range if known (psu), else salinity zone(s) according to the Venice system:
1. Limnetic [<0.5psu]
2. β-Oligohaline [0.5-3psu]
3. α-Oligohaline [3-5psu]
4. β-Mesohaline [5-10psu]
5. α-Mesohaline [10-18psu]
6. Polymixohaline [18-30psu]
7. Euhaline [30-40psu]
8. Hypersaline [>40psu]


Colonial. Descriptive of organisms produced asexually which remain associated with each other; in many animals, retaining tissue contact with other polyps or zooids as a result of incomplete budding.

Gregarious. Organisms living in groups or communities, growing in clusters.

Solitary. Living alone, not gregarious.

Sub-species level

A geographical subset of a species showing discrete differences in morphology, coloration or other features when compared with other members of the species. Subspecies may also differ in their habitat or behavior, but they can interbreed. Often the lowest taxonomic level within a classification system.


Valid synonyms of a species (not all of them).


Poisonous. An organism capable of producing poison that gains entry to another organism body via the gastrointestinal tract, the respiratory tract, or via absorption through intact body layers.

Venomous. An organism capable of producing poison, usually injected through another organism intact skin by bite or sting.

Not relevant. Neither poisonous nor venomous.

Public domain: Species account

Species Rhithropanopeus harrisii [WoRMS]
Authority (Gould, 1841)
Family Panopeidae  
Order Decapoda  
Class Malacostraca  
Phylum Arthropoda  
Synonym (?) Rhithropanopeus harrisii tridentatus (Maitland, 1874)
Panopeus wurdemannii (Gibbes, 1850)
Pilumnus harrisii (Gould, 1841)

References (not structured):
WoRMS database (World Register of Marine Species)
Sub-species level (?) Not known
Native origin (?) Ocean: Atlantic
--> Ocean region: NW Atlantic

References (not structured):
Roche DG, Torchin ME, Leung B, Binning SA (2009) Localized invasion of the North American Harris mud crab, Rhithropanopeus harrisii, in the Panama Canal: implications for eradication and spread. Biol Invasions 11:983–993

Williams (1965) in Roche
Torchin (2007)

"Recently, the North American Harris mud crab (Rhithropanopeus harrisii) was found in the waters (...)"
Worldwide : North-West Atlantic origin."
"Native range: North and Central American Atlantic Coast from the Gulf of the St. Lawrence River, Canada, to Vera Cruz, in the Gulf of Mexico (Williams, 1984). Williams (1984) corrected his erroneous listing of Brazil as part of R. harrisii native range."
Life form / Life stage (?)
 AdultJuvenileLarvaeEggsResting stage
Symbiont (non parasitic)

References (not structured):
Lohmann (1983) The Life Cycle of the Mud Crab. M. Phelan and M. Grubert, Coastal Research Unit, Fisheries, Darwin. March, 2007

Eggs remain attached to the mother’s pleopods until they hatch.
About 12 days after spawning, the eggs hatch, releasing the planktonic larval stage known as the zoea. (...) During the fifth moult, the larval crab transforms into a megalopa
with large (relative to its size), functional claws. This stage lasts seven to nine days,
during which the animal moves inshore and settles out of the plankton.
Sociability / Life stage (?)
 AdultJuvenileLarvaeEggsResting stage

References (not structured):
Lohmann (1983) The Life Cycle of the Mud Crab. M. Phelan and M. Grubert, Coastal Research Unit, Fisheries, Darwin. March, 2007

Eggs remain attached to the mother’s pleopods until they hatch.
Reproductive frequency (?) Iteroparous

References (not structured):
The Life Cycle of the Mud Crab. M. Phelan and M. Grubert, Coastal Research Unit, Fisheries, Darwin. March, 2007.
Turoboyski, 1973

Females reproduce normally every summer.
They carry eggs attached to the mother’s pleopods until they hatch.They usually lay between 1200 and 4800 eggs at a time depending on their size. In the Kiel Canal, Germany, large females were observed to lay as many as 16,000 eggs. About 12 days after spawning, the eggs hatch, releasing the planktonic larval stage known as the zoea.
Reproductive type (?) Sexual

The Life Cycle of the Mud Crab. M. Phelan and M. Grubert, Coastal Research Unit, Fisheries, Darwin. March, 2007.

They are oviparous and have sexual reproduction. Males place spermatophores into the female’s sprematheca, however they do not moult immediately before copulation. Approximately three to four days after copulation, females bury themselves up to the eye stalks to lay their eggs. This behaviour facilitates the attachment of the eggs to the pleopods. Ovigerous females will then remain sheltered in debris, shells, or sediment.
Developmental trait (?) Planktotrophy

The Life Cycle of the Mud Crab. M. Phelan and M. Grubert, Coastal Research Unit, Fisheries, Darwin. March, 2007.

After spawning, the eggs hatch, releasing the planktonic larval stage, known as the zoea.
Characteristic feeding method / Life stage (?)
 AdultJuvenileLarvaeEggsResting stage
Suspension feeder – ActiveX
Suspension feeder – PassiveXX
Deposit feeder – SurfaceXX
Deposit feeder – Sub-surface
Symbiont contribution

References (not structured):
The Life Cycle of the Mud Crab. M. Phelan and M. Grubert, Coastal Research Unit, Fisheries, Darwin. March, 2007.
Williams, 1984; Karpinsky, 2005.
Forsström et al.2015. An introduced species meets the local fauna: predatory behavior of the crab Rhithropanopeus harrisii in the Northern Baltic Sea. Biol Invasions 17:2729–2741.

Although mud crabs are omnivores and plant material and detritus is often found as part of their diet (Hegele-Drywa and Normant 2009), their major ecological role is predatory and their predatory effects may cascade to the level of producers.Known to feed on mangrove and leaf detritus, green algae, isopods, amphipods,shrimps, bivalve and gastropod molluscs, oligochaetes, dead and alive small fish. Small crabs have been observed to feed on small crustaceans such as amphipods and copepods.
Mobility / Life stage (?)
 AdultJuvenileLarvaeEggsResting stage
Temporary attachment
Permanent attachment

References (not structured):
The Life Cycle of the Mud Crab. M. Phelan and M. Grubert, Coastal Research Unit, Fisheries, Darwin. March, 2007.
Williams 1984, Petersen, 2006, Roche and Torchin 2007
Salinity tolerance range (?) Exact range: 0.5 - 40

Costlow JD, Bookhout CG, Monroe R (1966) Studies on the larval development of the crab, Rhithropanopeus harrisii (Gould). I. The effect of salinity and temperature on larval development. Physiol Zool 39:81–100
Paavola M, Olenin S, Leppäkoski E (2005) Are invasive species most successful in habitats of low native species richness across European brackish water seas? Estuarine, Coastal and Shelf Science 64 (2005) 738-750

Jazdzewski K, Konopacka A (2002) Invasive Ponto-Caspian species in waters of the Vistula and Oder Basins and the Southern Baltic Sea. In: Leppakoski E., Gollasch S. and Olenin S.(eds), Invasive Aquatic species of Europe - distribution impacts and management. Kluwer Academic Publishers, Dordrecht, Boston, London: 384-398

Adult crabs have been observed to migrate into freshwater (Williams, 1984). Low salinity is the most important factor limiting the distribution of R. harrisii larvae, which have reduced survival rates below 5 (Costlow et al. 1966, Christiansen and Costlow 1975, Cronin 1982, Gonçalves et al. 1995).
Still, reproducing populations have been found recently in water bodies with salinities as low as 0.4 (Keith 2008; Roche et al. 2009).
Habitat modifying ability potential (?) Keystone species

Culurgioni, J., Diciotti, R., Satta, C. T., Camedda, A., de Lucia, G. A., Pulina, S., ... & Fois, N. (2020). Distribution of the alien species Callinectes sapidus (Rathbun, 1896) in Sardinian waters (western Mediterranean). BioInvasions Record, 9(1).

Roche, Torchin (2007)
Zaitsev, Öztürk (2001).
Jormalainen, V., Gagnon, K., Sjöroos, J. and Rothäusler, E. 2016. The invasive mud crab enforces a major shift in a rocky littoral invertebrate community of the Baltic Sea. Biol.Invasions 18:1409–1419.

It can alter food webs. Increased Harris mud crab abundance could lead to a trophic cascade if abundances of grazers on epiphytes are reduced strongly. It may compete with, and potentially displace native crabs, crayfish, as well as benthophagous fishes. Also the crab has caused fouling of water intake pipes and economic loss to fishermen by spoiling fishes in gill nets as well.
Some fish species, perch, roach Rutilus rutilus (Linnaeus, 1758), and four-horned sculpin Myoxocephalus quadricornis (Linnaeus, 1758)(Fowler et al. 2013; Ovaskainen 2015) have included R.harrisii in their diet (Fowler et al. 2013).
Also birds such as goldeneyes (Bucephala clangula) and great cormorants (Phalacrocorax carbo sinensis) have been shown to prey on R. harrisii.
Toxicity / Life stage (?) Not relevant

Laughlin, R. B., & French, W. (1989). Population-related toxicity responses to two butyltin compounds by zoeae of the mud crab Rhithropanopeus harrisii. Marine Biology, 102(3), 397-401.

Laughlin, R., French, W., & Guard, H. E. (1983). Acute and sublethal toxicity of tributyltin oxide (TBTO) and its putative environmental product, tributyltin sulfide (TBTS) to zoeal mud crabs, Rhithropanopeus harrisii. Water, Air, and Soil Pollution, 20(1), 69-79.
Bioaccumulation association (?) Anthropogenic chemical compounds
Natural toxins

Walker, A. N., Bush, P., Puritz, J., Wilson, T., Chang, E. S., Miller, T., ... & Horst, M. N. (2005). Bioaccumulation and metabolic effects of the endocrine disruptor methoprene in the lobster, Homarus americanus. Integrative and Comparative Biology, 45(1), 118-126.

Wilman, B., Bełdowska, M., & Normant-Saremba, M. (2019). Labile and stable mercury in Harris mud crab (Rhithropanopeus harrisii) from the southern Baltic Sea–Considerations for a role of non-native species in the food web. Marine pollution bulletin, 148, 116-122.
Known human health impact? Not known

Not available.
Known economic impact? Not known

Not available.
Known measurable environmental impact? Known

AquaNIS. Editorial Board, 2015. Information system on Aquatic Non-Indigenous and Cryptogenic Species. World Wide Web electronic publication. Version 2.36+. Accessed 2021-07-23.
Kotta, J., Wernberg, T., Jänes, H., Kotta, I., Nurkse, K., Pärnoja, M., Orav-Kotta, H. 2018. Novel crab predator causes marine ecosystem regime shift. Scientific Reports, 8: 4956. DOI: 10.1038/s41598-018-23282-w

Triggers top-down control resulting in a decline in richness and biomass of benthic invertebrates, and an increase in pelagic nutrients and phytoplankton biomass (Kotta et al. 2018).
Included in the Target Species list? Yes

Assessed by the COMPLETE project experts (2021), included in target species list.
Association with vessel vectors (?) Ballast waters

Briski E, Ghabooli S, Bailey SA, MacIsaac HJ. 2012. Invasion risk posed by macroinvertebrates transported in ships’ ballast tanks. Biological Invasions, 14:1843–1850. DOI 10.1007/s10530-012-0194-0

The discovery of a live, gravid female R. harrisii in a ballast tank is particularly troubling discovery. This species may produce between 1,000 and 4,000 eggs per clutch, and females are able to release fertilized egg clutches up to four separate times following a single mating (Morgan et al. 1983). Thus, the propagule pressure exerted by such a female could approach that reported for juvenile stages previously (*30 individuals per m3 of unidentified decapod larvae in ballast water of coastal ships arriving to
the Atlantic coast of Canada (Briski et al., 2012)
Molecular information Available

Molecular information is available in GenBank under the accession numbers: MT758286-MT758299

Grosholz ED, Ruiz GM (1995) Does spatial heterogeneity and genetic variation in populations of the xanthid crab Rhithropanopeus harrisii (Gould) influence the prevalence of an introduced parasitic castrator? Journal of Experimental Marine Biology and Ecology, 187(1):129-145

In the crab’s native range, Grosholz and Ruiz (1995) looked for evidence supporting a genetic basis for resistance to the parasite L. panopaei in two different North American populations by estimating the heritability of susceptibility to infection.
Last update byMaiju Lehtiniemi, 2020-10-23