Illegal fishing in prohibited places, with prohibited fishing tools and methods, at prohibited times, in violation of the established rules. Poaching includes catching fish in excess of the norm (limit) determined by the control and protection authorities, or fish listed in the Red Book.

Poaching (from Fr. braconnier, "poacher"; originally "dog hunter") is defined as the illegal hunting, trapping or harvesting of wild animals, fish, seafood or plants, usually in connection with land rights. Poaching poses a serious threat to many wildlife species around the world and is a major cause of biodiversity loss.