Yes they are but I'm not sure that I would want to try one! A Polish friend gave me some Polish fishing magazines once and they have much the same fish over there as we do. I couldn't read a word of it but the fish were recogniseable (even if they did have different names!) and there was one fella holding a large tench. He was standing in his kitchen. I like them too much to eat one.
I know bream are edible because I once saw one about 8lbs on a fishmonger's slab in the Luton market. I think they get them from Ireland. The owner of a fishery I used to go to visited Ireland every year just to catch bream. Talk about a busman's holiday!
Also I've read that perch are delicious - and of course we know that pike are popular with travelling folk.