were having the same problems over here in norway, the eastern europeans are eating all the carp and pike. they've actually put signs up saying they must return several species (mostly pike and coarse fish). one good thing though, they love eel (yuck

).
last year i came across a group of polish guys who were catching and cooking everything they caught next to the water. it's pretty normal over here in norway to light a fire, and make some tea and food whilst you fish . i spoke to them and explained they're not allowed to eat pike or coarse fish(i speak a little polish), handed them a few trout spinners and wandered off. on my way back i came across them again . they called me over, sat me down, handed me a shot glass full of vodka and put a few freshly caught trout on the grill. i ended up showing them how to fly fish, and a few of them caught on pretty quickly. i ended up having to call my other half a few hours later as my plan to walk the 5 miles over the hills back to my house was hindered by blurry vision and rubber legs.
we exchanged numbers before they left, and since then we fish together quite regularly. three of the guys have been converted to avid fly fishers (even going as far as mocking their lure and spinner freinds

). they now understand why you cant eat all species of fish, and have a lot more respect for the places they fish. just goes to show what a little education, and a freindly face can do.
one thing i've found though, i've been to poland to many times, and there are very few places you need to buy a permit, with the exception of most game fishing areas (some fantastic rivers in the southern mountain areas too). maybe most of them just dont know any better. as i said, education is often the better solution where possible. remember, it's not just the eastern europeans who fish without a permit. i've came across more british people poaching than eastern europeans.