The descriptive text, below the map, is from the Cornish Red Data Book (2009). The map on this web page depicts the organisms distribution and shows the records made pre-2000 and those made since.
Range & Status
Native. Eurosiberian Southern-temperate aquatic species. Found scattered through
England and Wales south of a line from Morecambe Bay to the Humber, and in a small area between Glasgow and Edinburgh. Possibly under-recorded (Preston, Pearman & Dines, 2002).
It is restricted to a small part of the Bude Canal (SS20), where it has been known since 1919. However, it it has not been recorded since 1989, but probably still persists.
Habitat & Ecology
Found in the still or slow-moving waters of the Bude Canal.
The lower part of the Bude Canal is subject to much recreational activity, mostly boating. How much this disturbance may affect the population is not known.
The Bude Canal Regeneration Project, underway in 2008, aims to restore the first two miles of canal from the sea-lock to Helebridge. Work has included dredging the canal and lock-gate restoration, but the effect of this is not yet known.
I.J. Bennallick, S. Board, C.N. French, P.A. Gainey, C. Neil, R. Parslow, A. Spalding and P.E. Tompsett. eds. 2009. Red Data Book for Cornwall and the Isles of Scilly. 2nd Edition.Croceago Press.
The Cornish Red Data Book Project was led by the Cornwall and Isles of Scilly Federation for Biological Recorders (CISFBR). The full text and species accounts (minus the maps) are available on the CISFBR website.