BIOTIC

BIOTIC Species Information for Neopentadactyla mixta
All Taxonomy Biology Distribution Reproduction

Researched by	Angus Jackson	Data supplied by	MarLIN
Refereed by	Dr Andrew C. Campbell
Distribution and Habitat
Distribution in Britain & Ireland	All up the west coast of Scotland to Orkney and Shetland. A few isolated records from the east coast. Also from SW England, SW and NW Wales. In Ireland, particularly Kilkieran Bay, round the north and north-east, also the SE and SW corners.
Global distribution	South, west and north coasts of the British Isles, the Faeroe Islands, the west coast of Norway (Molde) and the Atlantic coasts of France.
Biogeographic range	Not researched	Depth range	15-70m
Migratory	See additional information
Distribution Additional Information	Although not necessarily representative of all populations, Neopentadactyla mixta exhibits regular daily and seasonal movements within the substratum. In the Kilkieran Bay population, individuals withdraw further into the sediment between 1 or 4 hours after sunrise and remain in the substratum for 1 or 2 hours, re-emerging over a period of up to four hours. In September/October the entire population withdraws into the substratum and re-emerges in March/April. They remain buried in aerobic conditions at depths of up to 60 cm with tentacles retracted and not feeding. Considerable loss of condition occurs during this time. Direct absorption of dissolved organic matter may be important for nutrition. This state of torpor is not complete, respiration and activity is greatly reduced but some movement within the substratum still occurs. Depth of burial is maintained despite surface changes in gravel with water movement.

Substratum preferences	Gravel / shingle Maerl	Physiographic preferences	Open coast Strait / sound Sealoch Ria / Voe
Biological zone	Lower Infralittoral Upper Circalittoral	Wave exposure	Exposed Moderately Exposed Sheltered Very 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	Mortensen, 1927, Konnecker & Keegan, 1973, Keegan, 1974,