@Clive
Well-known member
Thanks for the links.I've read quite a few texts about barbel. I tend to believe those that suggest that the Rhine system was the reason that barbel are native to England's easterly flowing rivers from the Humber to Thames. The suggestion being that at some point(s) in time, our eastern rivers have been Rhine tributaries. It's worth bearing in mind that, due to tectonics and glaciation, rivers have appeared, disappeared and changed courses massively over the millennia.
Here's some rather heavy reading and here's some fractionally lighter reading on the subject.
As for carp, I suspect that their introduction to the Danube is far more recent. I'd also doubt that they could ever colonise the higher reaches of the Danube naturally. That would make getting from Danube to Rhine rather more difficult than mere proximity might suggest. I find it fairly difficult to believe that the transit of carp from Asia right across Europe is remotely natural. I suspect that humans have had an awful lot to do with their movement. The difficulty is pinning down when and why it happened when archaeologists aren't exactly falling over each other looking for evidence. Romans? monks? barely anyone but anglers give a stuff.
The carp were transported by man, no doubt. As for the research: look out for articles by Richard Hoffman who is a lecturer in history at York and as an angler is part of many research initiatives throughout Europe. I have a book where he has overlayed the archeological evidence over the written evidence and mapped the finding by date. It clearly shows the Danube - Rhine route as the earliest references to carp in Europe.