1-877-TIPS-MNR
I seem to post this every year once or twice. If you see illegal activity call and report it. Take photos and licence numbers if possible. Call 2 or 3 or 4 times.
It may seem useless, but repeated calls will bring them out. I have seen it lots of times. If you are fishing a place where this happens regularly, maybe they won't show up on the day you witnessed offences happening, but they may show up the next day or the day after. And catch some law breakers. If you keep calling they will come.
Alfie.