BIOTIC

BIOTIC Species Information for Macoma balthica
All Taxonomy Biology Distribution Reproduction

Researched by	Lizzie Tyler	Data supplied by	University of Sheffield
Refereed by	This information is not refereed.
Distribution and Habitat
Distribution in Britain & Ireland	Common in estuarine environments around the British Isles, with the exception of the south coast.
Global distribution	Macoma balthica has an extensive geographic range that reaches from temperate to arctic coastal waters in both the North Atlantic and North Pacific oceans.
Biogeographic range	Not researched	Depth range
Migratory	Non-migratory / Resident
Distribution Additional Information	Studies have indicated that eastern and western North Atlantic populations of Macoma balthica are morphologically and genetically different from one another, and that they may have diverged as sibling species (Meehan & Carlton, 1988). Depth preferences Macoma balthica occurs in a wide depth range between the mid shore and 190m but is most abundant at moderate depths on muddy and sandy bottoms (Olafsson, 1986). However, in British waters Macoma balthica is mainly an intertidal species. Local distribution Macoma balthica is a resident species but because of near-surface habitat preference, populations may be subject to tidal re-location and scouring. Also observations of propulsion stimulus to scallops may assist in local relocation (Langston, W.J., pers. comm.)

Substratum preferences	Mud Muddy sand Sandy mud	Physiographic preferences	Ria / Voe Estuary Enclosed coast / Embayment
Biological zone	Upper Eulittoral Mid Eulittoral Lower Eulittoral	Wave exposure	Sheltered Very Sheltered Extremely Sheltered
Tidal stream strength/Water flow	Moderately Strong (1-3 kn) Weak (<1 kn)	Salinity	Variable (18-40 psu) Reduced (18-30 psu) Low (<18 psu)
Habitat Preferences Additional Information
Distribution References	Hayward et al., 1996, Hayward & Ryland, 1995b, Fish & Fish, 1996, Clay, 1967(b), Meehan & Carlton, 1988, Olafsson, 1986, Ratcliffe et al., 1981, Bonsdorff et al., 1995, Tebble, 1976, Picton & Costello, 1998, JNCC, 1999, Bruce et al., 1963, Hayward & Ryland, 1990, Julie Bremner, unpub data,