Harbour crab (Liocarcinus depurator)
Dorsal view of male and female.
Photographer: Keith Hiscock Copyright: Dr Keith Hiscock
Liocarcinus depurator in pre-mating position.
Photographer: Keith Hiscock Copyright: Dr Keith Hiscock
Liocarcinus depurator on a green background.
Photographer: Hilmar Hinz Copyright: Dr Hilmar Hinz
Liocarcinus depurator out of water.
Photographer: Holly Latham Copyright: Holly Latham
Liocarcinus depurator.
Photographer: Sue Scott Copyright: Sue Scott
Liocarcinus depurator.
Photographer: Crown copyright Copyright: Crown copyright
Comparative images of Liocarcinus species.
Photographer: Ivor Rees Copyright: Ivor Rees
Distribution data supplied by the Ocean Biodiversity Information System (OBIS). To interrogate UK data visit the NBN Atlas.Map Help
| Researched by | Jacqueline Hill | Refereed by | This information is not refereed |
| Authority | (Linnaeus, 1758) | ||
| Other common names | - | Synonyms | - |
Summary
Description
The carapace of Liocarcinus depurator is wider than long, about 51 mm wide and 40 mm long. The species is immediately recognised by the violet-tinted paddle of the fifth leg in larger crabs. The rest of the body is pale reddish-brown with transverse rows of hairs on the carapace, most conspicuous towards the rear.
Recorded distribution in Britain and Ireland
All British and Irish coasts.Global distribution
Distributed from Norway to West Africa including the Mediterranean.Habitat
Found on the lower shore and sublittoral on fine, muddy sand and gravel.Depth range
-5m to -300m+Identifying features
- Carapace broader than long, relatively flat, with numerous transverse, hairy, crenulations.
- The antero-lateral margins of the carapace have 5 pointed teeth.
- Wide orbits and three similar-sized rounded lobes between eyes.
- Front of carapace with a median lobe slightly more prominent than two similar flanking lobes.
- Chelipeds equal and stout.
- Pereopods 2-4 of slight build, pereopod 5 with violet tinted strongly paddled dactylus.
Additional information
Other common names include the 'swimming crab'.
Listed by
- none -
Biology review
Taxonomy
| Class | Malacostraca | Crabs, lobsters, sand hoppers and sea slaters |
| Family | Polybiidae | |
| Genus | Liocarcinus | |
| Authority | (Linnaeus, 1758) | |
| Recent Synonyms | ||
Biology
| Typical abundance | Moderate density | ||
| Male size range | Carapace width up to 56mm | ||
| Male size at maturity | Carapace width 30mm | ||
| Female size range | Carapace width 24mm | ||
| Female size at maturity | |||
| Growth form | Articulate | ||
| Growth rate | |||
| Body flexibility | None (less than 10 degrees) | ||
| Mobility | |||
| Characteristic feeding method | Predator, Scavenger | ||
| Diet/food source | |||
| Typically feeds on | Polychaetes, crustaceans, molluscs, ophiuroids and fishes constitute most of the diet (Freire, 1996). | ||
| Sociability | |||
| Environmental position | Demersal | ||
| Dependency | Independent. None | ||
| Supports | Host The polychaete worm Iphitime cuenoti and the parasitic nemertean Carcinonemertes carcinophila that live in the branchial chambers of some individuals. | ||
| Is the species harmful? | No The species is edible. It is frequently found in fish markets in the Mediterranean (Mori & Zunino, 1987). | ||
Biology information
- Size range and size at maturity: values given are for Mediterranean individuals (Muino et al., 1999).
- Feeding: Swimming crabs may exploit a wide range of dietary items including algae, sponges and many small invertebrates and may be considered omnivorous. However, Liocarcinus depurator is typically a scavenger and a carnivore. Freire et al. (1996) suggest the high diversity of food items in the diet of Liocarcinus depurator is due to the versatile functional structure of the chelipeds.
- Host for: Abelló et al., (1988) found 5% of individuals in the northwestern Mediterranean infested with the polychaete Iphitime cuenoti. No evidence of disease in the branchial chamber was found and the authors suggest a commensal relationship between the crab and the polychaete. However, the relationship may involve some degree of parasitism. In the Firth of Lorne the parasitic nemertean Carcinonemertes carcinophila was found the gills of over 90% of Liocarcinus depurator sampled (Comely & Ansell, 1989(b)).
Habitat preferences
| Physiographic preferences | Open coast, Offshore seabed, Strait / sound, Ria / Voe |
| Biological zone preferences | Circalittoral offshore, Lower circalittoral, Lower infralittoral, Sublittoral fringe, Upper circalittoral, Upper infralittoral |
| Substratum / habitat preferences | Coarse clean sand, Fine clean sand, Muddy gravel, Muddy sand |
| Tidal strength preferences | Moderately Strong 1 to 3 knots (0.5-1.5 m/sec.), Very Weak (negligible), Weak < 1 knot (<0.5 m/sec.) |
| Wave exposure preferences | |
| Salinity preferences | Full (30-40 psu) |
| Depth range | -5m to -300m+ |
| Other preferences | No text entered |
| Migration Pattern | No information found |
Habitat Information
Salinity: Liocarcinus depurator is essentially a marine species although a few individuals were found at the lower reaches of the Forth estuary where salinity varied between 24-35 psu (Mathieson & Berry, 1997).Life history
Adult characteristics
| Reproductive type | Gonochoristic (dioecious) | |
| Reproductive frequency | Annual protracted | |
| Fecundity (number of eggs) | 100,000-1,000,000 | |
| Generation time | ||
| Age at maturity | 1 year | |
| Season | See additional text | |
| Life span | Insufficient information |
Larval characteristics
| Larval/propagule type | - |
| Larval/juvenile development | Planktotrophic |
| Duration of larval stage | Not relevant |
| Larval dispersal potential | - |
| Larval settlement period | Insufficient information |
Life history information
- Time of gametes: In the northwestern Mediterranean female moult and copulation takes place between May and July (Abelló, 1989a).
- Spawning: Females with eggs occur all year (Ingle, 1997) although a maximum proportion of ovigerous females has been observed indicating the existence of an annual reproductive cycle. In Plymouth, ovigerous females are reported from March to October, from April to May in Bristol, January to June in the Clyde and Argyll and from January to May in Galway (Ingle, 1997). In the warmer waters of the northwestern Mediterranean numbers of ovigerous females peak in the winter months from November to February and males were found to be sexually mature throughout the year (Abelló, 1989a). In Plymouth, Liocarcinus depurator was found to incubate three or more batches of eggs over the spring and summer breeding season (Wear, 1974).
- Fecundity: The number of eggs carried by ovigerous females in the north western Mediterranean ranged from about 30,000 to 230,000 clearly increasing with the size of the female (Abelló, 1989a). However, a maximum of 140,000 eggs for the largest females was estimated in the Ligurian Sea (Mori & Zunino, 1987).
- Age at maturity: In the Gulf of Genoa in the Ligurian Sea Liocarcinus depurator females attain sexual maturity, are fertilized and bear eggs within the first year (Mori & Zunino, 1987).
- Larvae: in the plankton during spring and summer in British and North Sea waters (Ingle, 1980).
Sensitivity review
The MarLIN sensitivity assessment approach used below has been superseded by the MarESA (Marine Evidence-based Sensitivity Assessment) approach (see menu). The MarLIN approach was used for assessments from 1999-2010. The MarESA approach reflects the recent conservation imperatives and terminology and is used for sensitivity assessments from 2014 onwards.
Physical pressures
| Intolerance | Recoverability | Sensitivity | Evidence/Confidence | |
| Intermediate | High | Low | High | |
| Although a swimming crab, Liocarcinus depurator normally crawls on the seabed. The species only really swims in extremis. Therefore, substratum loss, such as caused by dredging, is likely to result in the loss of some individuals whilst others may be able to escape. Intolerance is therefore, assessed as intermediate. Recovery should be good because Liocarcinus depurator has planktonic larvae and is able to reproduce several times a year (Wear, 1974). | ||||
| Tolerant | Not relevant | Not sensitive | High | |
| Liocarcinus depurator is a mobile crab, able to crawl and also swim when necessary, and therefore unlikely to be affected by any smothering as it would be able to move up through the sediment or to an unaffected area. | ||||
| Tolerant | Not relevant | Not sensitive | Moderate | |
| Liocarcinus depurator is tolerant of changes in suspended sediment because it is a demersal species and feeds by predation and scavenging. The species is also able to move to more suitable conditions if necessary. | ||||
| No information | ||||
| Not relevant | Not relevant | Not relevant | High | |
| Liocarcinus depurator is a sub-littoral species and so desiccation is not relevant. | ||||
| Not relevant | Not relevant | Not relevant | High | |
| Emergence is not likely to occur in the species' preferred zone. | ||||
| No information | ||||
| Intermediate | High | Low | Low | |
| It is likely that the species is unable to keep its position on the benthos to feed and copulate in strong water flow and so intolerance has been assessed as intermediate. In laboratory experiments Liocarcinus depurator was unable to make progress towards bait in currents of 0.3m/s (0.6 knots) and 63% of animals were washed away (Nickell & Moore, 1992). However, the crab will drift in the water column or tumble along the seabed until quicker conditions occur. | ||||
| No information | ||||
| Intermediate | High | Low | High | |
| Liocarcinus depurator is likely to be tolerant of a range of temperatures consistent with a distribution north and south of Britain and Ireland populations and so will not be very intolerant of long term changes in temperature. Experiments with the species showed that a threefold decrease in egg incubation time of eggs can occur naturally in successive batches of eggs incubated during the early spring to mid-summer breeding season (Wear, 1974). At 13.1°C incubation time was 31.5 days and at 15.0 °C was 25.5 days. However, a rapid rise in water temperature of as little as 3°C can disrupt the natural sequence in the spawning and incubation of successive egg batches and also reduce fecundity by more than 90% (Wear, 1974) so that the viability of the population will be reduced. Intolerance is therefore assessed as intermediate. Very low water temperatures can cause mass mortalities of Liocarcinus spp.. During the severe winter of 1962-63 where water temperatures fell to 0°C for several weeks, many dead crabs were caught in research vessel trawls from the Dutch coast (Crisp, 1964). Recovery should be good because Liocarcinus depurator has planktonic larvae and is able to reproduce several times a year (Wear, 1974). | ||||
| No information | ||||
| Tolerant | Not relevant | Not sensitive | Moderate | |
| Liocarcinus depurator lives at depths of 300 m plus, is most active at night (Abelló et al., 1991), feeds by predation and scavenging on other invertebrates and is therefore, unlikely to be sensitive to changes in light brought about by increases in turbidity. The crab is commonly found in turbid conditions in harbours. | ||||
| No information | ||||
| Intermediate | Very high | Low | Low | |
| Liocarcinus depurator is a swimming crab and so is likely to be tolerant of some changes in wave exposure. However, it is likely that the species is unable to keep its position in areas of strong wave action so intolerance has been assessed as intermediate. The species also inhabits deep waters where wave action will have little impact. | ||||
| No information | ||||
| Tolerant | Not relevant | Not sensitive | Moderate | |
| Liocarcinus depurator is not likely to be sensitive to noise disturbance. | ||||
| Tolerant | Not relevant | Not sensitive | Moderate | |
| Crabs have well developed visual acuity and are likely to respond to movement in order to avoid predators. However, it is likely that the species will be little affected by visual disturbance caused by the continuous presence for one month of moving objects not naturally found in the marine environment (e.g., boats, machinery, and humans). Therefore, the species is assessed as not sensitive. | ||||
| High | High | Moderate | High | |
| Liocarcinus depurator was observed to be frequently injured and killed as a result of capture in a commercial 4m beam trawl (Kaiser & Spencer, 1995) and so an intolerance high has been recorded. Recovery should be good because Liocarcinus depurator has planktonic larvae and is able to reproduce several times a year (Wear, 1974). | ||||
| Tolerant | Not relevant | Not sensitive | High | |
| The species is highly mobile and probably not sensitive to displacement to another area. | ||||
Chemical pressures
| Intolerance | Recoverability | Sensitivity | Evidence/Confidence | |
| No information | Not relevant | No information | Not relevant | |
| Bryan & Gibbs (1991) report that crabs appear to be relatively resistant to TBT although some deformity of regenerated limbs has been observed. | ||||
| Intermediate | High | Low | Moderate | |
| Crompton (1997) reports that the concentrations above which mortality of crustaceans can occur is 0.01-0.1mg/l for mercury, copper and cadmium, 0.1-1mg/l for zinc, arsenic and nickel and 1-10mg/l for lead and chromium. Crustaceans are generally regarded as being more intolerant of cadmium than other groups (McLusky, 1986). However, crustaceans in general are less intolerant of most heavy metals than annelid worms and so intolerance has been assessed as intermediate. On return to normal conditions, recovery should be good because Liocarcinus depurator has planktonic larvae and reproduces several times a year. | ||||
| No information | No information | No information | Not relevant | |
| Insufficient information. | ||||
| No information | No information | No information | Not relevant | |
| Insufficient information. | ||||
| No information | No information | No information | Not relevant | |
| Insufficient information. | ||||
| Intermediate | High | Low | Moderate | |
| Liocarcinus depurator is essentially a marine species although a few individuals were found at the lower reaches of the Forth estuary where salinity varied between 24-35psu (Mathieson & Berry, 1997) and so intolerance is assessed as intermediate. Although the species is mobile and some individuals will be able to avoid unfavourable salinity changes, individuals are likely to be affected if salinity changes are widespread. On return to normal conditions, recovery should be good because Liocarcinus depurator has planktonic larvae and reproduces several times a year. | ||||
| No information | ||||
| High | High | Moderate | Moderate | |
| Cole et al. (1999) suggest possible adverse effects on marine species below 4 mg/l and probable adverse effects below 2mg/l. Crustaceans are generally less tolerant of hypoxia than polychaetes and bivalves and are rarely described from hypoxia stressed environments (Diaz & Rosenberg, 1995). Experiments looking at the resistance of marine invertebrates from the Baltic Sea, where temperature was 10°C and salinity 15psu, crustaceans had the shortest LD50 times (between 2 and 48 hours) at 0.15ml 02 (Theede et al., 1969). Therefore, a reduction in oxygen concentration to the benchmark level of 2mg/l for a week is expected to cause some individuals to die. Although the species is mobile and some individuals will be able to avoid hypoxic conditions changes individuals are likely to be affected if oxygen changes are widespread. On return to normal conditions recovery should be good because Liocarcinus depurator has planktonic larvae and reproduces several times a year. | ||||
Biological pressures
| Intolerance | Recoverability | Sensitivity | Evidence/Confidence | |
| Intermediate | High | Low | Moderate | |
| The incidence of black necrotic disease has been recorded for Liocarcinus depurator from sites on the west coast of Scotland (Comely & Ansell, 1989). The disease, which is believed to be caused by one or more of the chitinoclastic bacteria with secondary invasion by fungi, was found in the gills of almost 90% of Liocarcinus depurator. In the most extreme cases the gill lamellae were completely missing, only the blackened gill rachi being left. Intolerance has therefore, been assessed as intermediate. On return to normal conditions recovery should be good because the species has high fecundity and pelagic larvae. | ||||
| Tolerant | Not relevant | Not sensitive | High | |
| There are no known non-native species competing with Liocarcinus depurator. | ||||
| Intermediate | High | Low | High | |
| Liocarcinus depurator is often extracted as a by-catch species in benthic trawling. The species produces eggs several times a year which develop into planktonic larvae so recovery should be high. | ||||
| Tolerant | Not relevant | Not sensitive | Moderate | |
| Liocarcinus depurator has no known obligate relationships. | ||||
Additional information
Importance review
Policy/legislation
- no data -
Status
| National (GB) importance | - | Global red list (IUCN) category | - |
Non-native
| Native | - | ||
| Origin | - | Date Arrived | - |
Importance information
- Liocarcinus depurator is one of the most important by-catches of the Mediterranean demersal fishery (Abelló, 1989a).
- Enclosure experiments in a sea loch in Ireland have shown that high densities of this decapod led to a significant decline in infaunal organisms (Thrush, 1986).
Bibliography
Abelló, P., 1989. Reproduction and moulting in Liocarcinus depurator (Linnaeus, 1758) (Brachyura: Portunidae) in the Northwestern Mediterranean sea. Scientia Marina, 53, 127-134.
Abelló, P., Reid, D.G. & Naylor, E., 1991. Comparative locomotor activity patterns in the portunid crabs Liocarcinus holsatus and L. depurator. Journal of the Marine Biological Association of the United Kingdom, 71, 1-10.
Abelló, P., Sardá, R. & Masales, D., 1988. Infestation of some Mediterranean brachyuran crabs by the polychaete Iphitime cuenoti. Cahiers de Biologie Marine, 29, 149-162.
Bryan, G.W. & Gibbs, P.E., 1991. Impact of low concentrations of tributyltin (TBT) on marine organisms: a review. In: Metal ecotoxicology: concepts and applications (ed. M.C. Newman & A.W. McIntosh), pp. 323-361. Boston: Lewis Publishers Inc.
Comely, C.A. & Ansell, A.D., 1989. The incidence of Carcinonemertes carcinophila (Kolliker) on some decapod crustaceans from the Scottish west coast. Ophelia, 30, 225-233.
Comely, C.A. & Ansell, A.D., 1989. The occurrence of black necrotic disease in crab species from the west of Scotland. Ophelia, 30, 95-112.
Crisp, D.J. (ed.), 1964. The effects of the severe winter of 1962-63 on marine life in Britain. Journal of Animal Ecology, 33, 165-210.
Crompton, T.R., 1997. Toxicants in the aqueous ecosystem. New York: John Wiley & Sons.
Diaz, R.J. & Rosenberg, R., 1995. Marine benthic hypoxia: a review of its ecological effects and the behavioural responses of benthic macrofauna. Oceanography and Marine Biology: an Annual Review, 33, 245-303.
Fish, J.D. & Fish, S., 1996. A student's guide to the seashore. Cambridge: Cambridge University Press.
Freire, J., 1996. Feeding ecology of Liocarcinus depurator (Decapoda: Portunidae) in the Ría de Arousa (Galicia, north-west Spain): effects of habitat, season and life history. Marine Biology, 126, 297-311.
Freire, J., Sampedro, M.P. & Gonzalez-Gurriaran, E., 1996. Influence of morphometry and biomechanics on diet selection in three portunid crabs Marine Ecology Progress Series , 137, 111-121.
Hayward, P., Nelson-Smith, T. & Shields, C. 1996. Collins pocket guide. Sea shore of Britain and northern Europe. London: HarperCollins.
Hayward, P.J. & Ryland, J.S. (ed.) 1995b. Handbook of the marine fauna of North-West Europe. Oxford: Oxford University Press.
Howson, C.M. & Picton, B.E., 1997. The species directory of the marine fauna and flora of the British Isles and surrounding seas. Belfast: Ulster Museum. [Ulster Museum publication, no. 276.]
Ingle, R., 1997. Crayfishes, lobsters and crabs of Europe. An illustrated guide to common and traded species. London: Chapman and Hall.
Ingle, R.W., 1980. British Crabs. Oxford: British Museum (Natural History), Oxford University Press.
Mathieson, S. & Berry, A.J., 1997. Spatial, temporal and tidal variation in crab populations in the Forth estuary, Scotland. Journal of the Marine Biological Association of the United Kingdom, 77, 167-183.
McLusky, D.S., Bryant, V. & Campbell, R., 1986. The effects of temperature and salinity on the toxicity of heavy metals to marine and estuarine invertebrates. Oceanography and Marine Biology: an Annual Review, 24, 481-520.
Mori, M. & Zunino, P., 1987. Aspects of the biology of Liocarcinus depurator (L.) in the Ligurian Sea. Investigacion Pesquera, 51(suppl. 1), 135-145
Muino, R., Fernandez, L., Gonzalez-Gurriaran, E., Freire, J. & Vilar, J.A., 1999. Size at maturity of Liocarcinus depurator (Brachyura: Portunidae): a reproductive and morphometric study. Journal of the Marine Biological Association of the United Kingdom, 79, 295-303.
Nickell, T.D. & Moore, P.G., 1992. The behavioural ecology of epibenthic scavenging invertebrates in the Clyde Sea area: laboratory experiments on attractions to bait in moving water, underwater TV observations in situ and general conclusions. Journal of Experimental Marine Biology and Ecology, 159, 15-35.
Theede, H., Ponat, A., Hiroki, K. & Schlieper, C., 1969. Studies on the resistance of marine bottom invertebrates to oxygen-deficiency and hydrogen sulphide. Marine Biology, 2, 325-337.
Thrush, S.F., 1986. Community structure on the floor of a sea-lough: are large epibenthic predators important? Journal of Experimental Marine Biology and Ecology, 104, 171-183.
Wear, R.G., 1974. Incubation in British decapod crustacea, and the effects of temperature on the rate and success of embryonic development. Journal of the Marine Biological Association of the United Kingdom, 54, 745-762.
Datasets
Centre for Environmental Data and Recording, 2018. IBIS Project Data. Occurrence dataset: https://www.nmni.com/CEDaR/CEDaR-Centre-for-Environmental-Data-and-Recording.aspx accessed via NBNAtlas.org on 2018-09-25.
Centre for Environmental Data and Recording, 2018. Ulster Museum Marine Surveys of Northern Ireland Coastal Waters. Occurrence dataset https://www.nmni.com/CEDaR/CEDaR-Centre-for-Environmental-Data-and-Recording.aspx accessed via NBNAtlas.org on 2018-09-25.
Environmental Records Information Centre North East, 2018. ERIC NE Combined dataset to 2017. Occurrence dataset: http://www.ericnortheast.org.ukl accessed via NBNAtlas.org on 2018-09-38
Fenwick, 2018. Aphotomarine. Occurrence dataset http://www.aphotomarine.com/index.html Accessed via NBNAtlas.org on 2018-10-01
Fife Nature Records Centre, 2018. St Andrews BioBlitz 2015. Occurrence dataset: https://doi.org/10.15468/xtrbvy accessed via GBIF.org on 2018-09-27.
Fife Nature Records Centre, 2018. St Andrews BioBlitz 2016. Occurrence dataset: https://doi.org/10.15468/146yiz accessed via GBIF.org on 2018-09-27.
Isle of Wight Local Records Centre, 2017. IOW Natural History & Archaeological Society Marine Invertebrate Records 1853- 2011. Occurrence dataset: https://doi.org/10.15468/d9amhg accessed via GBIF.org on 2018-09-27.
Kent Wildlife Trust, 2018. Kent Wildlife Trust Shoresearch Intertidal Survey 2004 onwards. Occurrence dataset: https://www.kentwildlifetrust.org.uk/ accessed via NBNAtlas.org on 2018-10-01.
Manx Biological Recording Partnership, 2018. Isle of Man historical wildlife records 1990 to 1994. Occurrence dataset:https://doi.org/10.15468/aru16v accessed via GBIF.org on 2018-10-01.
Merseyside BioBank., 2018. Merseyside BioBank (unverified). Occurrence dataset: https://doi.org/10.15468/iou2ld accessed via GBIF.org on 2018-10-01.
National Trust, 2017. National Trust Species Records. Occurrence dataset: https://doi.org/10.15468/opc6g1 accessed via GBIF.org on 2018-10-01.
NBN (National Biodiversity Network) Atlas. Available from: https://www.nbnatlas.org.
OBIS (Ocean Biodiversity Information System), 2023. Global map of species distribution using gridded data. Available from: Ocean Biogeographic Information System. www.iobis.org. Accessed: 2023-06-02
South East Wales Biodiversity Records Centre, 2018. SEWBReC Myriapods, Isopods, and allied species (South East Wales). Occurrence dataset: https://doi.org/10.15468/rvxsqs accessed via GBIF.org on 2018-10-02.
Citation
This review can be cited as:
Last Updated: 17/04/2008
