BIOTIC Species Information for Flustra foliacea
|Researched by||Lizzie Tyler||Data supplied by||University of Sheffield|
|Refereed by||This information is not refereed.|
|Scientific name||Flustra foliacea||Common name||Hornwrack|
|MCS Code||Y187||Recent Synonyms||None|
|Additional Information||Flustra foliacea forms only a flat incrustation during its first year of growth, erect growth occurs in subsequent years. Fronds can often be encrusted by other bryozoans, hydroids and sedentary polychaetes.|
|Taxonomy References||Hayward & Ryland, 1995b, Hayward et al., 1996, Fish & Fish, 1996, Hayward & Ryland, 1998, Ryland, 1970, Ryland, 1967,|
|Feeding method||Passive suspension feeder
Active suspension feeder
|Typical food types||Phytoplankton, detritus and dissolved organic matter.||Habit||Attached|
|Bioturbator||Not relevant||Flexibility||High (>45 degrees)|
|Height||Up to 20 cm||Growth Rate||1.6-3 cm / year|
|Adult dispersal potential||None||Dependency||Independent|
|General Biology Additional Information||Detailed diagrams of the autozooid and avicularium of Flustra foliacea are provide by Silén (1977).
Stebbing (1971a) stated that the length of time spent as an encrusting form was unclear but assumed the first growth line at the base of the frond represented the first winter, 1 years growth. Flustra foliacea colonies regularly reached 6 years of age, although 12 year old specimens were reported off the Gower Peninsula (Stebbing, 1971a; Ryland, 1976). Furthermore, O'Dea & Okamura (2000) demonstrated seasonal fluctuations in zooid size synchronous with temperature regimes, the largest zooid zooids occurring with the lowest temperatures.
Stebbing (1971a) reported that growth rates were reasonably consistent between samples, age classes and years. Stebbing (1971a) reported a mean increment in frond height of 16.8mm/yr, whereas Eggleston (1972) reported that annual lines were usually between 2-3cm apart in Isle of Man specimens, and Menon (1978) reported that Helgoland specimens reached an average of 21.2 mm in height at 2 years old and an average of 79.3 mm after 8 years. Silén (1981) reported that erect fronds grew in zooid number about 10-20 times that of the encrusting base. Menon (1978) reported that growth rates varied in specimens over 5 years old.
At the base of fronds, in the holdfast area, the zooids give rise to layers of non-feeding frontal buds after 3 years of age, which strengthen the base of the frond. The number of layers increases with frond height up to 145mm in height, and up to 20 layers deep (Stebbing, 1971a).Growth rates probably vary between locations. O'Dea & Okumara (2000) noted that colonies of Flustra foliacea from the Bay of Fundy showed reduced growth compared to colonies in the Menai Straits and the Skagerrak. Low primary productivity, genetic variation and parasitism were cited as possible explanations for the difference.
Regeneration and repair
Some people can react to Flustra sp. and some fishermen have reported allergic reactions to it although this is anecdotal information (J. Porter, pers. comm.). Research into biomedical compounds from marine organisms has revealed that a sample of Flustra foliacea from the southern North Sea yielded deformylflustrabromine, which was moderately cytotoxic to the human colon cancer cell-line HCT-116 (Lysek et al., 2002; Jha & Zi-rong, 2004).
|Biology References||Hayward & Ryland, 1998, Ryland, 1970, Ryland, 1967, Silén, 1977, Ryland, 1976, Silén, 1981, Stebbing, 1971, Menon, 1978, Stebbing, 1971b, Nielsen R., 1975, Hincks, 1880, Stebbing, 1971a, Jha & Zi-rong, 2004, Lysek et al., 2002, Peters et al., 2003, O'Dea & Okamura, 2000, Hayward & Ryland, 1990, Julie Bremner, unpub data,|
|Distribution and Habitat|
|Distribution in Britain & Ireland||Common on all rocky coasts of Britain and Ireland.|
|Global distribution||Flustra foliacea occurs in the Kara Sea, White Sea and Barents Sea in the Arctic circle, the North Sea, and extends south as far as Bay of Biscay. Also found on the east coast of Greenland.|
|Biogeographic range||Not researched||Depth range|
|Migratory||Non-migratory / Resident|
|Distribution Additional Information||Flustra foliacea may colonize any hard substratum, such as shells, stones, or cobbles but forms dense aggregations particularly in otherwise barren, current swept rocky bottoms. Although present in a wide range of tidal streams and wave exposure, Flustra foliacea is abundant in moderately strong to strong tidal streams (Hiscock, 1983). Dyer et al. (1982) reported between <10 to >200 colonies per m² in trawls in the North Sea. Flustra foliacea is associated with strong currents and areas subject to sediment abrasion (Stebbing, 1971a; Knight-Jones & Nelson-Smith, 1977; Hartnoll, 1983; Holme & Wilson, 1985) and requires stable hard substrata (Eggleston, 1972b; Ryland, 1976; Dyrynda, 1994). The abundance of bryozoans is positively correlated with supply of stable hard substrata and hence with current strength (Eggleston, 1972b; Ryland, 1976).|
Large to very large boulders
|Physiographic preferences||Open coast
Strait / sound
Ria / Voe
|Biological zone||Upper Infralittoral
|Wave exposure||Very Exposed
|Tidal stream strength/Water flow||Very Strong (>6 kn)
Strong (3-6 kn)
Moderately Strong (1-3 kn)
Weak (<1 kn)
|Salinity||Full (30-40 psu)
|Habitat Preferences Additional Information|
|Distribution References||Hayward & Ryland, 1995b, Hayward et al., 1996, Fish & Fish, 1996, Hayward & Ryland, 1998, Ryland, 1970, Ryland, 1967, Ryland, 1977, Stebbing, 1971, JNCC, 1999, Picton & Costello, 1998, NBN, 2002, Dyer et al., 1982, Holme & Wilson, 1985, Hiscock, 1983, Hiscock, 1985 (b), Hartnoll, 1983, Knight-Jones & Nelson-Smith, 1977, Dyrynda, 1994, Eggleston, 1972b, Hincks, 1880, Hayward & Ryland, 1990, Julie Bremner, unpub data,|
|Reproductive type||Permanent hermaphrodite
|Reproductive Season||August to April||Reproductive Location||As adult|
|Reproductive frequency||Annual episodic||Regeneration potential||No|
|Life span||6-10 years||Age at reproductive maturity||< 1 year|
|Generation time||1-2 years||Fecundity||10000 (additional information)|
|Egg/propagule size||Fertilization type||Internal|
|Reproduction Preferences Additional Information||Reproduction
Bryozoan colonies are hermaphrodite, however, zooids may be monoecious, dioecious, protandrous or protogynous, depending on species (Hayward & Ryland, 1998). Flustra foliacea bears both male and female zooids and is presumably hermaphrodite.
Dalyell (cited in Hincks, 1880) stated that ca 10,000 larvae were released from a specimen of Flustra foliacea within 3 hrs. Eggleston (1972a) reported that each zooid produced a single embryo, so that fecundity is probably related to the number of sexual zooids and hence size of the colony.
Flustra foliacea colonies regularly reached 6 years of age, although 12 year old specimens were reported off the Gower Peninsula (Stebbing, 1971a; Ryland, 1976).
|Reproduction References||Hayward & Ryland, 1998, Ryland, 1970, Ryland, 1967, Ryland & Bishop, 1993, Ryland, 1977, Ryland, 1976, Dyrynda, 1994, Eggleston, 1972a, Eggleston, 1970, Hincks, 1880, Reed, 1991, Stebbing, 1971a, Julie Bremner, unpub data,|