Biodiversity & Conservation

Cordylophora caspia and Electra crustulenta on reduced salinity infralittoral rock



Image Keith Hiscock - Cordylophora caspia and Electra crustulenta on reduced salinity infralittoral rock. Image width ca 6 cm.
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Distribution map

IR.SIR.EstFa.CorEle recorded (dark blue bullet) and expected (light blue bullet) distribution in Britain and Ireland (see below)

  • EC_Habitats

Recorded distribution in Britain and Ireland

Recorded only in the upper reaches of the Tamar estuary, Plymouth, Devon.

Habitat preferences

Temperature range preferences - See additional information

Water clarity preferences - Low clarity / High turbidity
Poor clarity / Extreme turbidity

Limiting Nutrients - Data deficient

Other preferences - Low / Reduced salinity

Additional information

This biotope was recorded at the riverine/estuarine transition, from steeply broken shale bedrock at +1 to 3m deep, dominated by a 100% cover of Cordylophora caspia (as lacustris), and from deeper sloping horizontal bedrock with scattered Cordylophora caspia, frequent Electra crustulenta and rare Balanus spp. (Hiscock & Moore, 1986; Moore et al., 1999). At this site the salinity was reported to always below 20psu and could drop to zero. In nature, well developed colonies of Cordylophora caspia are usually found in water of 2 -12psu where tidal influence is considerable or between 2 -6psu where conditions are constant (Arndt, 1989). Arndt (1989) regarded Cordylophora caspia to be truly brackish water species, requiring eutrophic or hypertrophic conditions to maintain growth and reproduction, thermophilic but limited by low temperatures declining once temperatures drop below 5 °C and not regrowing in winter until temperatures exceed 10 °C (see species review for detail). Hayward & Ryland (1998) note that Electra crustulenta is limited to estuarine habitats but euryhaline in tolerance and probably widespread in distribution but commonly confused with other brackish water and estuarine species of encrusting bryozoans (e.g. Conopeum spp.).

This review can be cited as follows:

Tyler-Walters, H. 2002. Cordylophora caspia and Electra crustulenta on reduced salinity infralittoral rock. Marine Life Information Network: Biology and Sensitivity Key Information Sub-programme [on-line]. Plymouth: Marine Biological Association of the United Kingdom. [cited 29/11/2015]. Available from: <>