BIOTIC Species Information for Electra pilosa
Researched byDr Harvey Tyler-Walters Data supplied byMarLIN
Refereed byDr Peter J. Hayward
General Biology
Growth formCrustose hard
Feeding methodActive suspension feeder
Mobility/MovementPermanent attachment
Environmental positionEpifaunal
Typical food typesPhytoplankton, algal spores. HabitAttached
BioturbatorNot relevant FlexibilityNone (< 10 degrees)
FragilityFragile SizeSmall-medium(3-10cm)
Height Growth RateSpecific growth rate 0.08 / day
Adult dispersal potential10-100m DependencyIndependent
General Biology Additional InformationGrowth form
Electra pilosa displays a variety of growth forms, such as, stellate patches on flat substrata, cylindrical growths around algae to narrow tufts, and narrow bilaminar fronds or occasionally as spherical masses around small substrata, described earlier (see Ryland, 1967, 1976; and Silén, 1987 for reviews).
The median proximal spine may become greatly elongated in response to overgrowth by colonies of other bryozoans (Stebbing, 1973; Ryland, 1976) or in response to wave related abrasion by algae (Bayer et al., 1997). The extended spine may protect the feeding polypide from physical or mechanical disturbance (Bayer et al., 1997).

Growth rates
Growth rates in bryozoans have been shown to be vary with environmental conditions, especially water flow, food supply, temperature, competition for food and space, and genotype. For example:
  • Best & Thorpe (1986) reported that feeding rate increased with increasing food concentration;
  • Bayer et al. (1994) noted that variation in growth rates between colonies due to genotype was greater than that due to food ration;
  • Okamura (1988) reported that in epiphytic communities, feeding rate increased with increasing flow (from 0.01-0.02 m/sec to 0.1-0.12m/s) but was reduced by competing bryozoan communities (Alcyonidium sp. or Flustrellidra hispida) in slow flow but enhanced by them in fast flow conditions; and
  • bryozoans studied (inc. Electra pilosa) in natural currents in the Menai Strait, fed adequately and maintained growth even in very high current flows (Hermansen, et al., 2001).
  • Although growth rates increased with temperature, zooid size decreased, which may be due to increased metabolic costs at higher temperature (Menon, 1972; Ryland, 1976; Hunter & Hughes, 1994). In the Menai Straits larger zooids are produced in spring at times of peak phytoplankton primary productivity but mean zooid size decreased as temperatures increased in summer (Okamura, 1987 cited in Hunter & Hughes, 1994).
Growth rates of 0.1-0.12 µ /day were reported, irrespective of flow regime, and genotype, while natural population were reported to grow at ca 0.08 µ/ day (Hermansen et al., 2001).

The structure and function of the bryozoan lophophore was reviewed by Ryland (1976), Winston, (1977) and Hayward & Ryland (1998). Best & Thorpe (1994) suggested that intertidal Bryozoa would probably be able to feed on small flagellates, bacteria, algal spores and small pieces of abraded macroalgae.

Allergenic response
Electra pilosa and other bryozoans have been reported to cause dermatitis and occupational eczema in fishermen (Ryland, 1967; Jeanmougin et al., 1987 summary only).
Biology References Hayward & Ryland, 1995b, Hayward & Ryland, 1998, Ryland, 1967, Jeanmougin et al, 1987, Stebbing, 1973, Ryland, 1976, Bayer et al., 1997, Best & Thorpe, 1986, Bayer et al., 1994, Silén, 1987, Hermansen et al., 2001, Okamura, 1988, Ryland, 1977, Menon, 1972, Hunter & Hughes, 1994, Ryland, 1970, Best & Thorpe, 1994, Winston, 1977,
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