Almost 140 people have been prosecuted in the last 12 months in an ongoing battle against illegal fishing and poaching.
The anglers were caught committing a range of offences, from not having a rod licence to illegal netting and cruel 'foul hooking', which involves dragging hooks through the water at high speed in an attempt to impale fish on the hooks.
All but three of the 139 cases resulted in successful prosecutions and combined fines of £18,468, as well as the confiscation of equipment.
Natural Resources Wales warns illegal fishing is damaging to the angling industry, which is worth more than £150 million to the Welsh economy.
A spokesperson said: "Angling helps protect the environment, is a big draw for tourism and plays a major role in the local economy.
"It's important that we continue to crack down on illegal fishing activity so that it remains sustainable for licensed fisherman."