BIOTIC

BIOTIC Species Information for Pecten maximus
All Taxonomy Biology Distribution Reproduction

Researched by	Charlotte Marshall & Emily Wilson	Data supplied by	MarLIN
Refereed by	Andy Beaumont
Distribution and Habitat
Distribution in Britain & Ireland	Recorded around most coasts of Britain and Ireland, with only scattered records from the east coast of Great Britain.
Global distribution	Pecten maximus occurs along the European Atlantic coast from northern Norway, south to the Iberian peninsula and has also been reported off West Africa, the Azores, Canary Islands and Madeira.
Biogeographic range	Not researched	Depth range	10-110 m
Migratory	Non-migratory / Resident
Distribution Additional Information	Factors affecting distribution *Water flow and wave exposure* Pecten maximus tend to be most abundant just inside or just away from areas of strong currents (Mason, 1983). Gibson (1956) found that scallops living in sheltered areas grew faster than those on wave exposed beds and suggested that this was because the feeding apparatus become overwhelmed by particulate matter in the highly wave exposed areas. It is also possible that the delicate processes of larval settlement and byssal attachment would be disturbed in strong currents (Brand, 1991). *Substratum* The areas with highest abundance and the fastest growth rates of scallops are usually in areas with little mud (Brand, 1991). Gruffydd (1974) found that the maximum shell size of Pecten maximus from the north Irish Sea was significantly negatively correlated with increasing mud content in the sediment. *Aggregation and population subdivision* Adult scallops have a limited mobility and rely on the dispersal of larvae in terms of geographic distribution (Brand, 1991). The extent of this distribution will in turn be affected by factors including local hydrographic regimes and the survival of larvae. Consequently, all scallops have an aggregated distribution within their geographic range and the major fishing grounds are generally widely separated so much so that respective environmental conditions produce marked differences in population parameters (Brand, 1991). However, in terms of genetic differences, two principle genetic population studies of Pecten maximus (Beaumont et al., 1993; Wilding et al., 1998) have failed to identify any evidence of sub-population structure (Beaumont , 2005). Wilding et al. (1999) found that the population of Pecten maximus from Mulroy Bay was more similar to Pecten jacobaeus than it was to other Pecten maximus populations, implying that this population is genetically distinct from others. This genetic isolation is thought to arise as a result of the enclosed nature of Mulroy Bay which probably means that the population is sustained through self-recruitment (Beaumont, 2005).

Substratum preferences	Coarse clean sand Muddy sand Sandy mud Gravel / shingle Fine clean sand	Physiographic preferences	Offshore seabed Sealoch Enclosed coast / Embayment Open coast
Biological zone	Lower Infralittoral Upper Circalittoral Lower Circalittoral	Wave exposure	Exposed Sheltered Very Sheltered Extremely Sheltered
Tidal stream strength/Water flow	Moderately Strong (1-3 kn) Weak (<1 kn)	Salinity	Full (30-40 psu)
Habitat Preferences Additional Information
Distribution References	Ansell et al., 1991, Mason, 1983, Gibson, 1956, Tebble, 1976, Brand, 1991, Ansell et al., 1991, Beaumont & Zouros, 1991, Gruffydd, 1974, Picton & Costello, 1998, JNCC, 1999, NBN, 2002, Beaumont, 2005, Wilding et al., 1998, Wilding et al., 1999,