Abstract

The rheophilic European barbel Barbus barbus is an aggregative fish typically encountered in the middle reaches of European rivers that range from southeastern England and France in the west to the Black Sea basin in the east. An important angler-target species and indicator of anthropogenic disturbance, they are vagile, moving considerable distances for activities such as spawning when movements of over 20 km may be undertaken. Their habitat requirements vary with development; areas in the littoral zone with minimal flow are important for larvae, riffle areas for juveniles, and mid-channel habitats for adults. Within populations, individuals may be present to at least 18 years old, with the older, larger fish likely to be female. A range of threats to their populations exist, with the primary ones relating to aspects of river engineering that reduce habitat diversity (e.g., channelization) and river connectivity (e.g., flow gauging weirs) as this may impact nursery habitats and access to spawning gravels. Successful conservation and fishery management of barbel is thus reliant on sympathetic river management that maintains or restores habitat heterogeneity and connectivity.