BIOTIC Species Information for Maja squinado
Researched byEmily Wilson Data supplied byMarLIN
Refereed byThis information is not refereed.
Scientific nameMaja squinado Common nameCommon spider crab
MCS CodeS1515 Recent SynonymsNone

PhylumCrustacea Subphylum
Superclass ClassEumalacostraca
SubclassEucarida OrderDecapoda
SuborderPleocyemata FamilyMajidae
GenusMaja Speciessquinado

Additional Information
Taxonomy References Howson & Picton, 1997, Hayward & Ryland, 1995b, Hayward et al., 1996, Ingle, 1980,
General Biology
Growth formArticulate
Feeding methodOmnivore
Environmental positionEpibenthic
Typical food types HabitFree living
Bioturbator FlexibilityNone (< 10 degrees)
FragilityFragile SizeMedium(11-20 cm)
HeightInsufficient information Growth RateInsufficient information
Adult dispersal potential>10km DependencyIndependent
General Biology Additional InformationUp to 22.5 cm carapace length (Ingle, 1997). Although solitary, forms aggregated 'mounds' of individuals in late summer / autumn (Fish & Fish, 1996).
Biology References Fish & Fish, 1996, Ingle, 1997,
Distribution and Habitat
Distribution in Britain & IrelandWest and south-west coasts of Britain. It is at its northern limit in the UK.
Global distributionNE Atlantic from Ireland to Guinea (W Africa) and Med to 150 m (Ingle, 1997).
Biogeographic rangeNot researched Depth rangeDown to ca 75 m.
MigratoryInsufficient information   
Distribution Additional Information

Substratum preferencesBedrock
Coarse clean sand
Fine clean sand
Physiographic preferencesInsufficient information
Biological zoneInsufficient information
Wave exposureInsufficient information
Tidal stream strength/Water flowInsufficient information
SalinityInsufficient information
Habitat Preferences Additional InformationFound on rocky sandy bottoms. Usually inhabits weed covered substrata or sandy / shingly substrata where weeds occur (Ingle, 1997).
Distribution References Hayward & Ryland, 1995b, Hayward et al., 1996, NBN, 2002, JNCC, 1999, Picton & Costello, 1998, Hardy & Guiry, 2003, Morton, 1994, Ingle, 1997,
Reproduction/Life History
Reproductive typeGonochoristic
Developmental mechanismPlanktotrophic
Reproductive SeasonSummer - Autumn Reproductive LocationAs adult
Reproductive frequencyAnnual protracted Regeneration potential No
Life spanInsufficient information Age at reproductive maturity1-2 years
Generation timeInsufficient information Fecundity156,000 (Hartnoll, 1963)
Egg/propagule sizeInsufficient information Fertilization typeInternal
Larval/Juvenile dispersal potential1km-10km Larval settlement periodInsufficient information
Duration of larval stage2-10 days   
Reproduction Preferences Additional InformationMaturity 2 years in the Med (Hines et al., 1995). Main breeding season in south-west England between July - September (Lebour, 1927) and March - Sept in Ireland (Rodhouse, 1984). NE Atlantic in general, females bear eggs between March and October (Ingle, 1997). Time taken to reach the megalopa stage was reported to take ca 1 week in the laboratory (Lebour, 1927). In the Ría de Arousa, Spain, Maja squinado were reported to have moved up to 10.7 km within one month (González-Gurriarán & Freire, 1994). González-Gurriarán et al., (1993) estimated females to produce at least three consecutive broods during the yearly cycle. This is possible due to the storage of sperm which allows consecutive broods without the need for copulation before spawning (González-Gurriarán et al., 1996). In the UK and Ireland, only one brood is produced per yearly cycle (Rodhouse, 1984). In this species, the crabs do not moult again after becoming sexually mature i.e. the terminal moult is the pubertal moult.
Reproduction References González-Gurriarán & Freire, 1994, González-Gurriarán et al, 1996, Rodhouse, 1984, Lebour, 1927, Ingle, 1997, Hartnoll, 1963,
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