BIOTIC Species Information for Psammechinus miliaris
Researched byLizzie Tyler Data supplied byUniversity of Sheffield
Refereed byThis information is not refereed.
Distribution and Habitat
Distribution in Britain & IrelandAll British and Irish coasts. Evenly distributed in the southern North Sea but scarce in northern North Sea.
Global distributionFrom Trondheim Fjord in northern Norway, inner Danish waters from the Skaw into the western Baltic, Iceland, British Isles, south to the Atlantic coast of Morocco and the Azores. Not in Greenland, the Mediterranean or Atlantic coasts of America.
Biogeographic rangeNot researched Depth range0 - 100 m
MigratoryNon-migratory / Resident   
Distribution Additional InformationThe species is found in the intertidal and subtidal, occasionally as deep as 100 m (Mortensen, 1927) but more commonly between 16 -70 m (Cranmer, 1985) or 0 -10 m in Scottish sea lochs (Kelly, 2000).

On the west coast of Scotland Psammechinus miliaris typically occurs in dense, localized populations in sheltered areas of sea lochs (Davies, 1989; Holt, 1991). Its distribution frequently coincides with that of the brown seaweed %Laminaria saccharina%, with Psammechinus miliaris occurring on the fronds as well as on rock surfaces below the fronds. Some populations are exposed to air at low spring tides, and are found attached to the underside of rocks, boulders and seaweed, or shallowly buried under gravel on the foreshore (Kelly, 2000). Individuals from the intertidal and subtidal habitats on the west coast of Sweden were termed 'Z' and 'S' forms by Lindahl & Runnström (1929). The 'Z' form lived in the 'seaweed region' and were larger and darker than the 'S' forms found at greater depths.

Comely (1979) described a population of Psammechinus miliaris from a %Zostera marina% bed in a stable salinity, shallow inlet in Loch Sween, Scotland. Theses individuals were found on the bottom mud and attached to the rhizomes of Zostera at depths of 1 -2 m. Very young individuals have been found in the holdfasts of Laminaria from the Clyde Sea, Scotland (Moore, 1971).

Psammechinus miliaris is often found on man-made surfaces such as bridge supports and wrecks.

Substratum preferencesLarge to very large boulders
Muddy gravel
Artificial (e.g. metal/wood/concrete)
Under boulders
Small boulders
Gravel / shingle
Muddy sand
Physiographic preferencesOpen coast
Offshore seabed
Strait / sound
Ria / Voe
Biological zoneMid Eulittoral
Lower Eulittoral
Sublittoral Fringe
Upper Infralittoral
Lower Infralittoral
Upper Circalittoral
Lower Circalittoral
Wave exposureModerately Exposed
Very Sheltered
Extremely Sheltered
Tidal stream strength/Water flowModerately Strong (1-3 kn)
SalinityVariable (18-40 psu)
Full (30-40 psu)
Habitat Preferences Additional Information
Distribution References Hayward & Ryland, 1995b, Hayward et al., 1996, Gage, 1991, Cranmer, 1985, Bedford & Moore, 1985, Allain, 1978, Hancock, 1957, Rasmussen, 1973, Mortensen, 1927, Jensen, 1969, Bruce et al., 1963, MBA, 1957, Massin, 1999(b), Aquascope, 2000(a), Kelly & Cook, 2001, Lindahl & Runnström, 1929, Comely, 1979, Davies, 1989, Holt, 1991, Ursin, 1960, Larsson, 1968, Leighton, 1995, Moore, 1971, Hayward & Ryland, 1990, Julie Bremner, unpub data,
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