BIOTIC Species Information for Ahnfeltia plicata
Researched byWill Rayment Data supplied byMarLIN
Refereed byDr Fabio Rindi
Scientific nameAhnfeltia plicata Common nameA red seaweed
MCS CodeZM186 Recent SynonymsNone

PhylumRhodophycota Subphylum
Superclass ClassRhodophyceae
SubclassFlorideophycidae OrderAhnfeltiales
Suborder FamilyAhnfeltiaceae
GenusAhnfeltia Speciesplicata

Additional Information
Taxonomy References Fish & Fish, 1996, Dickinson, 1963, Dixon & Irvine, 1977, Maggs & Pueschel, 1989, Howson & Picton, 1997,
General Biology
Growth formFoliose
Crustose soft
Feeding methodPhotoautotroph
Mobility/MovementPermanent attachment
Environmental positionEpilithic
Typical food typesNot relevant HabitAttached
BioturbatorNot relevant FlexibilityHigh (>45 degrees)
FragilityIntermediate SizeMedium(11-20 cm)
Height Growth RateSee additional information
Adult dispersal potentialNone DependencyIndependent
General Biology Additional InformationGrowth rate
Maggs & Pueschel (1989) recorded observations on growth of Ahnfeltia plicata from Nova Scotia. 4 months after germination of carpospores, tetrasporophyte crusts had grown up to 2.6 mm in diameter. 2 months after germination of tetraspores, the basal holdfast had reached 1.1 mm in diameter, with numerous hair like fronds emerging. After 14 months the axes had grown up to 50 mm in length.
In a continuous spray culture with water at 8-11°C and light intensities of 40-60 µE/m²/s, mean apical growth of Ahnfeltia plicata was 17.2 µm/day over 19 days (Indergaard et al., 1986). Permanently immersed plants under the same conditions grew at approximately 7 µm/day. Conversely, percentage biomass increase was greater under the permanent immersion regime; 0.57% increase in mass/day vs. 0.20% for the plants in spray culture (Indergaard et al., 1986).
Biology References Fish & Fish, 1996, Dickinson, 1963, Dixon & Irvine, 1977, Maggs & Pueschel, 1989, Indergaard et al., 1986, Bird et al., 1991,
Distribution and Habitat
Distribution in Britain & IrelandOccurs on all coasts of Britain and Ireland. There is a paucity of records from south east England, reflecting a lack of suitable substrata.
Global distributionOccurs in Europe from northern Russia to southern Portugal and in the Baltic Sea. Occurs in the Americas from arctic Canada to Mexico and is widely distributed in the Indian and Pacific Oceans.
Biogeographic rangeNot researched Depth rangelower shore to 22 m
MigratoryNon-migratory / Resident   
Distribution Additional InformationLüning (1990) suggested that Ahnfeltia plicata typically occurs as an understory algae beneath Laminaria sp. at depths of 1.5 to 4 m.

Substratum preferencesBedrock
Coarse clean sand
Physiographic preferencesOpen coast
Strait / sound
Enclosed coast / Embayment
Biological zoneLower Eulittoral
Upper Infralittoral
Sublittoral Fringe
Lower Infralittoral
Wave exposureExposed
Moderately Exposed
Tidal stream strength/Water flowModerately Strong (1-3 kn)
Weak (<1 kn)
SalinityFull (30-40 psu)
Variable (18-40 psu)
Reduced (18-30 psu)
Habitat Preferences Additional Information
Distribution References Fish & Fish, 1996, Dickinson, 1963, Dixon & Irvine, 1977, Maggs & Pueschel, 1989, Lüning, 1990, JNCC, 1999, Picton & Costello, 1998, Lewis, 1964, Connor et al., 1997(a), Hardy & Guiry, 2003,
Reproduction/Life History
Reproductive typeVegetative
Permanent hermaphrodite
See additional information
Developmental mechanismSpores (sexual / asexual)
Reproductive SeasonInsufficient information Reproductive Location
Reproductive frequencyAnnual protracted Regeneration potential No
Life span6-10 years Age at reproductive maturity1-2 years
Generation timeInsufficient information FecundityNo information found
Egg/propagule size Fertilization type
Larval/Juvenile dispersal potentialInsufficient information Larval settlement period
Duration of larval stageInsufficient information   
Reproduction Preferences Additional InformationLife span
No information was found concerning the longevity of Ahnfeltia plicata. However, it is a slow maturing perennial (Dickinson, 1963) and the thallus survives several years without considerable losses (Lüning, 1990). It likely to have a life span of 5-10 years, similar to other red seaweeds, such as Furcellaria lumbricalis.

Age at maturity
No definitive information was found concerning age at maturity. However, Maggs & Pueschel (1989) made observations of Ahnfeltia plicata from Nova Scotia. Tetrasporophyte crusts matured and released tetraspores after 15 months. Gametangial plants had produced abundant monosporangia after 14 months but no other reproductive structures were formed during this time.

Reproductive type
Ahnfeltia plicata has a heteromorphic life history (Maggs & Pueschel, 1989). Carpospores formed on the female thallus as a result of sexual reproduction give rise to the tetrasporophyte encrusting form. In turn, the tetraspores formed on the tetrasporophyte phase give rise to the erect, gametophyte plants. However, male gametophytes also give rise to monosporangia, producing monospores which also develop into gametophytes. Maggs & Pueschel (1989) suggest that the recycling of erect male gametophytes may be important in habitats which are unsuitable for the encrusting phase.

Timing of reproduction
Maggs & Pueschel (1989) recorded observations of reproduction by Ahnfeltia plicata in Nova Scotia. Spermatangia were present on male gametophytes between July and January. Carpogonia were present on female gametophytes between July and November, carposporophytes began development between September and November, and were mature between October and July. Monosporangia, which were only found on male plants in the intertidal, were present from November to January.
Reproduction References Dickinson, 1963, Dixon & Irvine, 1977, Maggs & Pueschel, 1989, Lüning, 1990,
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