BIOTIC Species Information for Arenicola marina
Researched byDr Harvey Tyler-Walters Data supplied byMarLIN
Refereed byDr Matt Bentley
Scientific nameArenicola marina Common nameBlow lug
MCS CodeP931 Recent SynonymsNone

PhylumAnnelida Subphylum
Superclass ClassPolychaeta
Subclass OrderCapitellida
Suborder FamilyArenicolidae
GenusArenicola Speciesmarina

Additional InformationArenicola defodiens sp. nov. has recently been distinguished from Arenicola marina on the basis of the morphology of the gills, the annulation pattern between the first 4 chaetigerous segments, size, burrow depth, cast type and shape, colour, absence of a feeding depression and genetic polymorphism (see Cadman & Nelson-Smith, 1993). These two species may represent the 'laminarian' and 'littoral' forms respectively referred to by earlier authors.
Taxonomy References Fish & Fish, 1996, Hayward & Ryland, 1995b, Hayward et al., 1996, Howson & Picton, 1997, Cadman & Nelson-Smith, 1993, Everson, 2000,
General Biology
Growth formVermiform segmented
Vermiform annulated
Feeding methodSub-surface deposit feeder
Environmental positionInfaunal
Typical food typesMicro-organisms (bacteria), benthic diatoms, meiofauna, and detritus. HabitBurrow dwelling
BioturbatorInsufficient information FlexibilityHigh (>45 degrees)
FragilityFragile SizeMedium(11-20 cm)
HeightNot relevant Growth RateInsufficient information
Adult dispersal potential100-1000m DependencyIndependent
General Biology Additional Information
  • The anatomy of Arenicola marina was described in detail by Ashworth (1904).
  • Arenicola marina burrows into sediment using its proboscis and muscular contractions of the first few segments. It forms a J-shaped burrow (see image) with a vertical shaft and horizontal limb in which the worm lies head first. Arenicola marina ingests sediment at head end of the burrow forming a feeding column and characteristic funnel or 'blow hole' on the surface (Wells, 1945; Zebe & Schiedek, 1996). Therefore, it feeds on material obtained from the sediment surface. The shape and different feeding characteristics of the funnel were discussed and photographed by Rijken (1979).
  • Arenicola marina ingests small particles (<2mm) which stick to the proboscis papillae while larger particles are rejected and accumulate in the vicinity of the burrow, often resulting in a characteristic layer of shell material below the burrow found in sediments populated by this species (Zebe & Schiedek, 1996; Riisgård & Banta, 1998).
  • Arenicola marina feeds on micro-organisms (bacteria), meiofauna and benthic diatoms in the sediment and is also capable of absorbing dissolved organic matter (DOM) such as fatty acids through the body wall (Zebe & Schiedek, 1996).
  • Feeding, defaecation and burrow irrigation is cyclic. Each cycle takes about 42 minutes in large worms but 15 min in smaller worms, depending on individual. Each cycle consists of defaecation (worm mainly in the tail-shaft), followed by rapid irrigation and a longer period of feeding, after which the worm defaecates again and the cycle repeats (Wells, 1949; Russell-Hunter, 1979; Riisgård & Banta, 1998)
  • The burrow is irrigated (and therefore aerated) by intermittent cycles of peristaltic contractions of the body from the tail to the head end. Therefore, fresh water is taken in at the tail end and leaves by percolation through the feeding column.
  • Arenicola marina can extract 32 -40% of the oxygen in burrow water, mainly through the gills but partly through the body surface. The blood has a high oxygen carrying capacity due to the presence of high concentrations of extracellular haemoglobin. At low tide, when supply of fresh water is not available, movement is reduced to a minimum.
  • Arenicola marina is capable of anaerobic metabolism in hypoxic conditions (see Zeber & Schiedek, 1996 for review).
  • Tail-nipping by flatfish, Nereis virens, and Hediste diversicolor results in loss of a few tail segments, which are not replaced, tail length being made up by increasing the length of the remaining segments. The tail is important for the storage of faeces. Storage of faeces minimises defaecation at the surface, and therefore resultant risk of predation. Tail-nipping results in decreased overall growth (de Vlas, 1979).
  • Newell (1948) noted that the average length of adult Arenicola marina decreased over-winter then rapidly increased in spring to reach a maximum in September.
  • Ashworth (1904) recorded the presence of Distomid cercariae and Coccidia in Arenicola marina from the Lancashire coast.
Biology References Fish & Fish, 1996, Hayward & Ryland, 1995b, Hayward et al., 1996, Cadman & Nelson-Smith, 1993, Everson, 2000, Ashworth, 1904, Zebe & Schiedek, 1996, Hayward, 1994, Wells, 1945, Beukema & de Vlas, 1979, Vlas de, 1979, Rijken, 1979, Wilde & Berghuis, 1979, Wells, 1949, Russell-Hunter, 1979., Farke & Berghuis, 1979, Dillon & Howie, 1997, Riisgård & Banta, 1998, Clay, 1967,
Distribution and Habitat
Distribution in Britain & IrelandFound on all coasts around Britain and Ireland and widely in north-west Europe.
Global distributionRecorded from shores of western Europe, Norway, Spitzbergen, north Siberia, and Iceland. In the western Atlantic it has been recorded from Greenland, along the northern coast form the Bay of Fundy to Long Island. Its southern limit is about 40° N.
Biogeographic rangeNot researched Depth rangeIntertidal
MigratoryNon-migratory / Resident   
Distribution Additional InformationNone entered

Substratum preferencesSalt marsh
Muddy gravel
Muddy sand
Sandy mud
Fine clean sand
Physiographic preferencesStrait / sound
Ria / Voe
Enclosed coast / Embayment
Isolated saline water (Lagoon)
Biological zoneUpper Eulittoral
Mid Eulittoral
Lower Eulittoral
Sublittoral Fringe
Wave exposureModerately Exposed
Very Sheltered
Tidal stream strength/Water flowVery Strong (>6 kn)
Strong (3-6 kn)
Moderately Strong (1-3 kn)
Weak (<1 kn)
Very Weak (negligible)
SalinityFull (30-40 psu)
Variable (18-40 psu)
Reduced (18-30 psu)
Habitat Preferences Additional InformationArenicola marina reaches its highest abundance at mid-tidal levels on muddy sandy shores, except in summer when another zone of abundance occurs on the upper shore due to migration of juveniles (see larval information). Population density is correlated with mean particle size and organic content of the sediment. Arenicola marina is generally absent from sediments with a mean particle size of <80µm and abundance declines in sediments >200µm (fine sand) because they can not ingest large particles. Its absence from more fluid muddy sediments is probably because they do not produce large amounts of mucus with which to stabilise their burrows. Populations are greatest in sands of mean particle size of 100µm. Between 100-200µm the biomass of Arenicola marina increases with increasing organic content (Longbottom, 1970; Hayward, 1994). However, juveniles prefer medium particle sizes (ca. 250 µm) over fine or coarse sand (see general biology - larval) (Hardege et al., 1998).
Distribution References Fish & Fish, 1996, Ashworth, 1904, Zebe & Schiedek, 1996, Hayward, 1994, Dales, 1958, Longbottom, 1970, Shumway & Davenport, 1977, Beukema & de Vlas, 1979, Farke & Berghuis, 1979, Cadman, 1997, Clay, 1967, Hardege et al., 1998, Barnes, 1994,
Reproduction/Life History
Reproductive typeGonochoristic
Developmental mechanismOviparous
Reproductive Seasonautumn - winter Reproductive LocationAdult burrow
Reproductive frequencyAnnual episodic Regeneration potential No
Life span6-10 years Age at reproductive maturity1-2 years
Generation time1-2 years FecunditySee additional information
Egg/propagule sizeInsufficient information Fertilization typeExternal
Larval/Juvenile dispersal potential1km-10km Larval settlement periodNot relevant
Duration of larval stageNot relevant   
Reproduction Preferences Additional Information
  • Eggs and early larvae develop within the female burrow, however post larvae are capable of active migration by crawling, swimming in the water column and passive transport by currents e.g. Günther (1992) suggested that post-larvae of Arenicola marina were transported distances in the range of 1 km.
  • Wilde & Berghuis (1979b) reported 316,000 oocytes per female with an average wet weight of 4g.
  • Beukema & de Vlas, (1979) suggested a life span, in the Dutch Wadden Sea, of at least 5-6 years, and cite a life span of at least 6 years in aquaria. They also suggested an average annual mortality or 22%, an annual recruitment of 20% and reported that the abundance of the population had been stable for the previous 10 years. However, Newell (1948) reported 40% mortality of adults after spawning in Whitstable.
  • Adults reach sexual maturity by their second year (Newell, 1948; Wilde & Berghuis, 1979) but may mature by the end of their first year in favourable conditions depending on temperature, body size, and hence food availability (Wilde & Berghuis, 1979).
Gametogenesis and spawning:
  • Germ cells released from gonads at meiotic prophase I.
  • Spermatogenesis and oogenesis occur within the coelomic cavity. Sperm are released into the coelomic cavity in packets or sperm morulae. Release of gametes from the body cavity, and in the case of sperm by the prior breakdown of morulae, is under endocrine control by a 'maturation factor'. The 'maturation factor' is released by a neurosecretory organ, the prostomium (Bentley & Pacey, 1992; Pacey 2000). Sperm maturation factor stimulates breakdown of sperm morulae and spawning.
  • Spawning takes place within the burrow.
  • Spawning of gametes occurs due to rhythmic contractions of the body wall, and the gametes are released via the nephridia (Bentley & Pacey, 1992).
  • Sperm motility is stimulated by the change in pH as the sperm are released into seawater (i.e. from pH 7.3 in the coelomic cavity to pH 8.2 in seawater).
  • Spawned sperm are flushed out of the burrow by pumping activity of the male, whilst oocytes are retained in the horizontal shaft of the female's burrow.
  • After spawning males fasted for 2 days while females fasted for 3-4 weeks, presumably to avoid ingesting eggs and larvae (Farke & Berghuis, 1979).
  • Once spawned sperm remain motile for over 5 hours at 14 °C. (Pacey, 2000), form puddles on the sediment surface and are dispersed by the incoming tide. Eggs (oocytes) are retained in the females burrow (Bentley & Pacey, 1992).
  • Sperm swim intermittently, perhaps in response to light, and Pacey (2000) suggested that this may be an adaptation to downward swimming towards the eggs.
  • Spermatogenesis, sperm maturation and oocyte maturation have been in studied in detail by Bentley & Pacey (1989), Bentley & Pacey (1992), Watson & Bentley (1995), and Watson & Bentley (1998). A comparative study of gametogenesis in Arenicola marina and Arenicola defodiens was carried out by Watson et al. (1998).
Factors influencing spawning:
  • Spawning usually occurs in late autumn or early winter but may occur in early spring (Pacey, 2000).
  • Spawning is inhibited by temperatures above 13 or 15 °C (depending on study) (Bentley & Pacey, 1992).
  • Synchronous spawning is associated with spring or neap tides suggesting a correlation with tidal or lunar cycles (Howie, 1959; Bentley & Pacey, 1992).
  • Watson et al., (2000) examined Arenicola marina population on East Sands, St. Andrews and suggested that synchronous spawning was dependant on a number of environmental cues, i.e. once gametogenesis is complete (about late summer depending on population) a drop in sea temperature - of defined, but unknown magnitude - triggers endocrine stimulation of spawning. Synchronous spawning is then is triggered by spring tides, probably due to changes in hydrostatic pressure rather than lunar phase.
  • Warm summer temperatures (ca May to July) may facilitate gametogenesis, due to increase metabolic rate and food availability, allowing the population to mature earlier and hence spawn earlier (Watson et al., 2000).
  • Watson et al. (2000) suggested that the East Sands population spawned preferentially in clement weather (high pressure, low rainfall and wind speed), when sperm dilution (due to wave action) is minimal. Inclement weather coincident with spring tides resulted in the population wide spawning being aborted on the East Sands in 1996 (Watson et al., 2000).
  • Individuals within a given locality may spawn synchronously, e.g. at East Sands, St. Andrews, over a period of 13 years observation spawning time varied by 5 weeks, but was synchronous over a period of 4-5 days (Watson et al., 2000).
  • The exact timing of spawning varies between locations and some populations demonstrate protracted spawnings. For example, on sandy shores near St Andrews and Dublin spawning occurred between mid October to mid November, peaking in early November, whereas at Fairlie Sans, Millport spawning occurred between Apr and May and again in autumn (Howie, 1959; Bentley & Pacey, 1992). Dillon & Howie (1997) reported marked differences in timing of synchronous spawning or protracted spawnings in populations of Arenicola marina from the east coast of Ireland, even though separated by no more than 85 miles. The reported spawning periods of Arenicola marina were reviewed by Clay (1967; Table 1).
Reproduction References Fish & Fish, 1996, Bentley & Pacey, 1992, Pacey, 2000, Ashworth, 1904, Hayward, 1994, Newell, 1948, Howie, 1959, Bentley & Pacey, 1989, Watson & Bentley, 1995, Watson & Bentley, 1998, Wilde & Berghuis, 1979, Newell, 1949, Günther, 1992, Wilde & Berghuis, 1979(b), Farke & Berghuis, 1979, Dillon & Howie, 1997, Watson et al., 1998, Beukema, 1995, Clay, 1967,
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