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.
Habitat & Distribution
A sedentary fish either solitary or in small schools over sand or mud in depths down to 30m. In spring they congregate, often in large numbers, in more shallow, brackish waters in coastal lagoons and estuaries. Once considered to be a rare fish in northern European waters it has become much more common in recent years. Its range extends south from south-west England, south and west Wales, south and south-west Ireland, along the Atlantic coast of France, Spain and Portugal, into the Mediterranean, and down to Ghana on the west coast of Africa. Large numbers of young and older fish have recently, post 2000, been recorded from various Cornish estuaries: Camel, Hayle, Penryn, Mylor, the Fal and Helford, etc., strongly suggesting that this species is now breeding in Cornish waters.
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.