These are some fish which don't give a damn about the lure, they will catch about anything they see (if they see the hook, the will catch the hook, if you attach a leaf or a small stick it will be better). When fishing with fly the fly looks like nothing you can find in nature, its the movement which counts mostly.
But this can be abstracted anyway - most anglers I know use mostly either synthetic lures or something they can catch at the site, like snails or earthworms. They sometimes experiment and make special baits (usually when they are unsuccessful at first), like from potato, or maize, but of course these couldn't be used in ancient Europe... Rice could be used, but not in Finland. Bread and wheat products are considered good baits, too. I think making it too realistic would make too much hassle - for example if you are targetting breams in real life, they like big bait, like several white worms at once, or even a sandwich, and probably won't get caught on something smaller (you will get a roach or similar instead). But in the game, kind of fish caught depends on something else, including apparently supernatural influence.
The anglers do use fishing bait, which I don't know English name for, which is thrown into water BEFORE fishing, and even if they don't want to fish on a particular day. It is used to keep the fish nearby and make them less skittish in future. This uses more baiting substance than actual fishing. But if the engine would support this - I doubt it.
Also - berries? I've never heard about berries used as a bait. And baiting nets is also a technique I'm unaware of.