We are conducting a large project at the moment, pit-tagging fish in order to look at the effectiveness of low-cost solutions (specifically low-cost baffles and pre-barrages) at improving fish passage over gauging structures. The project is going well, with large numbers of both coarse fish and brown trout having been tagged, released back into the river systems and their subsequent movements monitored. Very early indications appear to suggest that both the low-cost baffles and pre-barrage solution enable fish to move up and over the gauging weirs on which these solutions have been installed. The final results will certainly be very interesting as they will have a significant bearing on the potential solutions that can be used to improve fish passage at gauging weirs.
The images below show an anaesthetised chub having a pit-tag inserted, and the site where a pre-barrage has been installed, with the pit-tag loop installed above the weir crest.