BIOTIC

BIOTIC Species Information for Balanus crenatus

Researched by

Nicola White

Data supplied by

MarLIN

Refereed by

Prof. Alan J. Southward

Taxonomy

Scientific name

Balanus crenatus

Common name

An acorn barnacle

MCS Code

R77

Recent Synonyms

None

Phylum

Crustacea

Subphylum

Superclass

Class

Maxillopoda

Subclass

Cirripedia

Order

Thoracica

Suborder

Balanomorpha

Family

Balanidae

Genus

Balanus

Species

crenatus

Subspecies

Additional Information

No text entered

Taxonomy References

Rainbow, 1984, Bassindale, 1964,

General Biology

Growth form

Conical

Feeding method

Passive suspension feeder
Active suspension feeder

Mobility/Movement

Permanent attachment

Environmental position

Epifaunal
Epilithic

Typical food types

Zooplankton and other organic particles of a suitable size, such as detritus and phytoplankton.

Habit

Attached

Bioturbator

Not relevant

Flexibility

None (< 10 degrees)

Fragility

Robust

Size

Small(1-2cm)

Height

Insufficient information

Growth Rate

4.4 mm/month

Adult dispersal potential

None

Dependency

Independent

Sociability

Gregarious

Toxic/Poisonous?

General Biology Additional Information

Balanus crenatus has a calcareous base, while Semibalanus balanoides has a membranous base.
Feeding
Balanus crenatus feeds by extending thoracic appendages called cirri out from the shell to filter zooplankton from the water. In the absence of any current, the barnacle rhythmically beats the cirri. When a current is present Balanus crenatus holds the cirri fully extended in the current flow. Barnacles feed most during spring and autumn when plankton levels are highest. Little if any feeding takes place during winter, when barnacles rely on stored food reserves. Feeding rate is important in determining the rate of growth.
Moulting
Barnacles need to moult in order to grow. Frequency of moulting is determined by feeding rate and temperature. Moulting does not take place during winter when phytoplankton levels and temperatures are low.
Size:
Balanus crenatus is hermaphroditic and grows up to 25mm in diameter.

Biology References

Rainbow, 1984, Barnes et al., 1963, Bassindale, 1964,

Distribution and Habitat

Distribution in Britain & Ireland

All coasts of Britain & Ireland, and offshore in the North Sea and Celtic Sea.

Global distribution

Northeast Atlantic from the Arctic to the west coast of France as far south as Bordeaux; east and west coasts of North America and Japan.

Biogeographic range

Not researched

Depth range

Insufficient information

Migratory

Non-migratory / Resident

Distribution Additional Information

Balanus crenatus is a widespread species that occurs at quite high latitudes in the Arctic. It colonizes a wide range of substrata, attaching to any hard substrata, molluscs and their dead shells (Southward, pers. comm.), often as an initial colonizing species. Densely packed colonies occur particularly in areas exposed to strong tidal streams where few other epifauna survive. It can also be found attached to carapaces of the Norway lobster or Dublin Bay prawn (Nephrops norvegicus) and other crustaceans.
Balanus crenatus may have been misidentified as Solidobalanus fallax in shallow waters lying to the south of the UK. The deep water record of Gruvel (noted in Southward, 1998) is an error (Southward, pers. comm.). Balanus crenatus and Solidobalanus fallaxcolonize different substrates and also occur in different temperatures. Solidobalanus fallax occurs in warmer water on shells, false corals, seaweeds and other soft substrata, including plastic bags and synthetic netting (Southward, pers. comm.).

Substratum preferences

Bedrock
Artificial (e.g. metal/wood/concrete)
Cobbles
Gravel / shingle
Large to very large boulders
Pebbles
Small boulders

Physiographic preferences

Open coast
Offshore seabed
Strait / sound
Sealoch
Ria / Voe
Estuary
Enclosed coast / Embayment

Biological zone

Lower Eulittoral
Sublittoral Fringe
Upper Infralittoral
Lower Infralittoral

Wave exposure

Extremely Exposed
Very Exposed
Exposed
Moderately Exposed
Sheltered
Very Sheltered
Extremely Sheltered

Tidal stream strength/Water flow

Very Strong (>6 kn)
Strong (3-6 kn)
Moderately Strong (1-3 kn)
Weak (<1 kn)
Very Weak (negligible)

Salinity

Full (30-40 psu)
Reduced (18-30 psu)
Variable (18-40 psu)
Low (<18 psu)

Habitat Preferences Additional Information

Distribution References

Rainbow, 1984, Barnes, 1953, Barnes et al., 1963, JNCC, 1999, Bassindale, 1964, Southward, 1998,

Reproduction/Life History

Reproductive type

Permanent hermaphrodite

Developmental mechanism

Planktotrophic
Lecithotrophic

Reproductive Season

February to September

Reproductive Location

As adult

Reproductive frequency

Annual episodic

Regeneration potential

Life span

1-2 years

Age at reproductive maturity

<1 year

Generation time

<1 year

Fecundity

Insufficient information

Egg/propagule size

Insufficient information

Fertilization type

Larvae/Juveniles
Larval/Juvenile dispersal potential	>10km	Larval settlement period	Insufficient information
Duration of larval stage	11-30 days

Reproduction Preferences Additional Information

Balanus crenatus is an obligate cross-fertilizing hermaphrodite. Nauplii larvae are released from the barnacle between February and September, with peaks in April and late summer when phytoplankton levels are highest. However, release is not synchronised with the spring algal bloom, unlike Semibalanus balanoides.
Nauplii larvae are planktotrophic and develop in the surface waters. They pass through six nauplii stages before eventually developing into a cyprid larva. Cyprid larvae are specialised for settlement. They drift and swim in the plankton before selecting a suitable substratum for settlement and metamorphosis. Peak settlement occurs in April and declines until October. Metamorphosis usually takes place within 24 hours of settlement.
Barnacles grow rapidly except in winter. April-settled individuals may release larvae the same July and reach full size before their first winter. Individuals that settled later reach maximum size by the end of spring the following year (Rainbow, 1984).
Balanus crenatus has a life span of 18 months (Barnes & Powell, 1953). Growth rate varies greatly with the degree of current flow and the presence of silt. Balanus crenatus populations attached to Nephrops norvegicus grew only 2mm in 4 months, whereas populations on rafts grew at 0.2mm per day. This reduction in growth in epizoic populations is attributed to the higher presence of silt and reduction in water currents (Barnes & Bagenal, 1951).

Reproduction References

Rainbow, 1984, Barnes & Powell, 1953, Barnes & Bagenal, 1951,