This was a special fishing holiday near Pontivy in Brittany to fish the River Blavet and the Nantes-Brest Canal which it flows in and out of. I had heard from blogs on-line, and also a reliable report on Anglers Net, that the roach (to 1lb 8 oz) and bream (to 6lbs) fishing here was prolific, with nets of around 50lbs regularly available in a session. Also the locals mainly fish for predators, to be taken away and eaten, so I assumed the roach and bream wouldn't be too 'hook shy.'
Alas, that is not how it turned out! In the whole week I had 6 roach (best 8oz, and the others small) and one tench from the canal of a bit over a pound.
What was the explanation? Doubtless it was partly my lack of local knowledge and angling skill, but if the river had been as prolific as I had expected I think I would have caught more than I did. The reports were from 5 or 6 years ago, and I wonder if the river hasn't declined. The owner of the gite where I stayed said they had huge numbers of cormorants, mainly in the winter months. Alternatively, there was a story in the local press, apparently, of a mass of silt being let through from a hydro-electric station a couple of miles upstream. I don't see why this should have been such a problem, except for a day or two, but apparently there were dead fish.
A side issue is that, particularly in the canal, the fish were more cunning than I expected, with expertly smashed maggots while there was no bite registered on the float or ledger. But that was not the main issue.
I would be interested in any theories, but I guess the moral for me is to be wary of old information!