BIOTIC Species Information for Liocarcinus depurator
Researched byLizzie Tyler Data supplied byUniversity of Sheffield
Refereed byThis information is not refereed.
Scientific nameLiocarcinus depurator Common nameBlue-leg swimming-crab
MCS CodeS1580 Recent SynonymsNone

PhylumCrustacea Subphylum
Superclass ClassEumalacostraca
SubclassEucarida OrderDecapoda
SuborderPleocyemata FamilyPortunidae
GenusLiocarcinus Speciesdepurator

Additional InformationOther common names include the 'swimming crab'.
Taxonomy References Howson & Picton, 1997, Hayward & Ryland, 1995b, Hayward et al., 1996, Fish & Fish, 1996,
General Biology
Growth formArticulate
Feeding methodPredator
Environmental positionDemersal
Typical food typesPolychaetes, crustaceans, molluscs, ophiuroids and fishes constitute most of the diet (Freire, 1996). HabitFree living
BioturbatorNot relevant FlexibilityNone (< 10 degrees)
FragilityFragile SizeSmall-medium(3-10cm)
HeightInsufficient information Growth RateInsufficient information
Adult dispersal potential1km-10km DependencyIndependent
General Biology Additional 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)).
Biology References Mori & Zunino, 1987, Abelló et al., 1988, Freire, 1996, Comely & Ansell, 1989(b), Muino et al., 1999, Abelló et al., 1991, Freire et al., 1996, Hayward & Ryland, 1990, Julie Bremner, unpub data,
Distribution and Habitat
Distribution in Britain & IrelandAll British and Irish coasts.
Global distributionDistributed from Norway to West Africa including the Mediterranean.
Biogeographic rangeNot researched Depth range0 - 450 m
MigratoryInsufficient info.   
Distribution Additional 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).

Substratum preferencesMuddy gravel
Muddy sand
Fine clean sand
Coarse clean sand
Physiographic preferencesOpen coast
Offshore seabed
Strait / sound
Ria / Voe
Biological zoneSublittoral Fringe
Upper Infralittoral
Lower Infralittoral
Upper Circalittoral
Lower Circalittoral
Circalittoral Offshore
Wave exposure
Tidal stream strength/Water flowModerately Strong (1-3 kn)
Weak (<1 kn)
Very Weak (negligible)
SalinityFull (30-40 psu)
Habitat Preferences Additional Information
Distribution References Hayward & Ryland, 1995b, Hayward et al., 1996, Ingle, 1997, Mathieson & Berry, 1997, Hayward & Ryland, 1990, Julie Bremner, unpub data,
Reproduction/Life History
Reproductive typeGonochoristic
Developmental mechanismPlanktotrophic
Reproductive SeasonYear round Reproductive LocationWater column
Reproductive frequencyAnnual protracted Regeneration potential No
Life spanInsufficient information Age at reproductive maturity1 year
Generation timeInsufficient information Fecundity130000
Egg/propagule size Fertilization typeInternal
Larval/Juvenile dispersal potentialInsufficient information Larval settlement periodInsufficient information
Duration of larval stage   
Reproduction Preferences Additional 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).
Reproduction References Abelló, 1989a, Ingle, 1997, Mori & Zunino, 1987, Ingle, 1980, Wear, 1974, Julie Bremner, unpub data,
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