[lokerfoi]

Is it so hard to just put microchips that identify the owner into these animals?

Just imagine how easy it would be to punish the citizens releasing animals into the wilderness if micro-chipping was mandatory. No need to ban imports, nothing.

[pvaldes]

Micro chips can be removed, and some people just don't care the small probability to face a fine (that will not cover the 0,00001% of the economical damage caused in any case)