The below maps were derived from the crucian fisheries list by Andrew Cooper. Additions, corrections and additional information on new or existing fisheries can be emailed to the list's curator Mark Wintle.
These maps were derived from the fisheries list from April 2020, some 388 fisheries.
These maps are interesting and useful, but are dependent on the provision of data, which by its nature will be skewed by local knowledge in some areas.
Couple of interesting points:
Firstly there appears to be a lot of fisheries, especially 'unclassified', in the West Country, Devon particularly. This may be a consequence of the creation of many small fisheries to cater for the holiday trade.
Secondly, Dorset and Hampshire are well represented and this may be a consequence of this website's local knowledge.
Lastly, Norfolk shows up well, especially for classified fisheries. This might be the influence of the The Pond Restoration Research Group. Some of their crucian centric conservation work can be seen here.
These maps were derived from the fisheries list from February 2021, some 360 fisheries. This reduction is due in part to the removal of a number of duplicates and defunct fisheries, some removed at the start of 2020 by the curator of the list, Mark Wintle, then again in 2021, when 'webmaster JAA' trawled the entire list with an eye on the mechanics of converting data for web-page inclusion.
These maps were derived from the same data set as those immediately above, but a further map has been added to show only 'A+B' graded fisheries. If anything this highlights those areas where the most is known about crucian fisheries and they are centred on Dorset/Hampshire/Berkshire/Surrey and Norfolk/Lincolnshire.
As previously intimated, this tells us more about where the landscape is well known, rather than a true distribution of the crucian and I suspect there are many small ponds over the country harbouring populations.
For example, the Ashford area of Kent has so many small ponds it is hardly possible to cross a field without falling in one (put "TN27 8JZ" into ‘google maps'). The area between Preston and Blackpool has a similar scattering of small ponds.
Crucian populations in any such ponds will probably only come to light as a result of local knowledge.