BIOTIC

BIOTIC Species Information for Thyasira gouldi
All Taxonomy Biology Distribution Reproduction

Researched by	Angus Jackson	Data supplied by	MarLIN
Refereed by	This information is not refereed.
Distribution and Habitat
Distribution in Britain & Ireland	At the head of Loch Etive, west coast of Scotland. Formerly also found in Lochs Linnhe, Eil and Sunart. Recorded also from Shetland (further detail lacking). Presence in Scottish waters forms the extreme southern end of the geographic range.
Global distribution	A pan-arctic distribution from waters of the Commonwealth of Independent States along the north coast of Norway, around the coast of Greenland. On American coasts as far south as Cape Cod on the east and California on the west coast.
Biogeographic range	Not researched	Depth range	15-25m
Migratory	Non-migratory / Resident
Distribution Additional Information	Geographic distribution was probably more general during the last glaciation and remaining populations are relicts. The populations in Lochs Linnhe and Eil have been killed by the discharge of pulp-mill effluent. The population in Loch Etive has also decreased massively between 1984 and 1989. It is possible that this decrease has been brought about by a viral infection of the mutualistic bacteria living on the gills of Thyasira gouldi. Digestion of the bacteria provides considerable nutrient input. This species can burrow up to ten times its shell length (max. 8cm) and uses its vermiform foot to create channels deeper into the sediment. A mucus lined inhalant tube is made up to the surface from the living chamber. Little information is available about preferred water flow rates but are probably quite low being at the head of a sea loch. Wave exposure preferences are also likely to be sheltered. Typical depths in Scottish waters are 15-25 metres but the species has been found down to a few hundred metres depth. Optimal salinity levels are 25-30 psu. Thyasira gouldi appears to be restricted to locations where bottom waters remain cool throughout the year as a result of salinity stratification.

Substratum preferences	Muddy sand Mud Sandy mud	Physiographic preferences	Sealoch
Biological zone	Lower Infralittoral Upper Circalittoral Lower Circalittoral	Wave exposure	Insufficient information
Tidal stream strength/Water flow	Insufficient information	Salinity	Reduced (18-30 psu)
Habitat Preferences Additional Information
Distribution References	Blacknell & Ansell, 1975, Southward, 1986, Blacknell & Ansell, 1974, Bowden & Heppel, 1973, Southward & Southward, 1991, Dando & Southward, 1986,