Biodiversity & Conservation

Limaria hians beds in tide-swept sublittoral muddy mixed sediment



Image Sue Scott - Gaping file shell nest on mixed muddy substratum, with nest opened and Limaria hians exposed. Image with ca 15 cm.
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Distribution map

SS.SMx.IMx.Lim recorded (dark blue bullet) and expected (light blue bullet) distribution in Britain and Ireland (see below)

  • EC_Habitats
  • UK_BAP

Marine natural heritage importance

Listed under EC Habitats Directive
UK Biodiversity Action Plan
National importance Scarce
Habitat Directive feature (Annex 1) Large shallow inlets and bays

Biotope importance

The Limaria hians carpet or reef provides firm substratum for the attachment of macroalgae (in shallow waters) and sessile or sedentary epifauna, and provides additional niches for interstitial species and refugia from predation for others. As a result the gaping file shell reef modifies the nature of the substratum, stabilizes the sediment, affects the turnover of nutrients and organic material, and increases biodiversity (Minchin, 1995; Hall-Spencer & Moore, 2000b). The reef probably provides a locally important food source for mobile predators such as crabs, starfish and some fish and supplies reproductive propagules and larvae to the zooplankton. For example, Hall-Spencer & Moore (2000b) reported juvenile cod Gadus morhua feeding on the reef at Creag Gobhainn, Loch Fyne. Minchin (1995) reported that the Limaria hians reef in Mulroy Bay, Co. Donegal, provided substratum for kelps and their associated diverse community (e.g. see EIR.LhypR), which in turn provided cover for young cod Gadus morhua and saithe Pollachius virens (as Gadus). The kelp community was dependant on the Limaria hians reef and subsequent loss of the reef due to TBT contamination (see sensitivity) resulted in loss of the kelp beds and juvenile gadoids (Minchin, 1995). Therefore, gaping file shell reefs may be of significant importance to their local ecosystems. Hall-Spencer & Moore (2000b) reported that the abundance of Limaria hians had declined, especially in the Clyde Sea and off the Isle of Man, probably due to scallop dredging over the past 30 years. Hall-Spencer & Moore (2000b) concluded that Limaria hians reefs supported a diverse assemblage of macroalgae and invertebrates and suggested that Limaria hians beds should be given the same conservation status as other biogenic reefs (for definition see Holt et al., 1998).


Limaria hians is not known to be subject to exploitation. However, Hall-Spencer & Moore (2000b) reported that exploitation of other species (scallops) found in the vicinity of Limaria hians beds was probably responsible for a significant decline in Limaria hians numbers (see sensitivity). Lobsters and crabs are also targeted by potting on the Loch Fyne Limaria hians beds but no evidence of damage has been seen (Hall-Spencer, pers comm.).

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This review can be cited as follows:

Tyler-Walters, H. 2003. Limaria hians beds in tide-swept sublittoral muddy mixed sediment. Marine Life Information Network: Biology and Sensitivity Key Information Sub-programme [on-line]. Plymouth: Marine Biological Association of the United Kingdom. [cited 25/11/2015]. Available from: <>