I have over the years caught many coho on the Squamish river, but have never once caught a hatchery marked Coho.. out of hundreds of fish - so they are exceptionally rare to catch on that system.
I witnessed two individuals fishing with 3 rods on the Squamish river and retaining wild coho. When asked if they knew they were only supposed to keep one hatchery fish, one of the men attempted to hide his fish out of view from me, which had already had its head cut off. I plainly saw the adipose fin on the coho, and said, "that is not a hatchery fish", to which the man responded, "it is", and then I said, "No it isn't, it has an adipose fin", and he then shrugged and put the fish inside a black garbage bag and into his large backpack. I informed a local Squamish FN man who was also fishing in the area and he said he would have a word with them. Anyway - watch for these guys, and if you see them poaching be sure to call the DFO. They aptly drive a white chevy van with the roof component named "Get-Away". Quite literally a get-away van.
The men were between 50-60 years of age, with harsh eastern european accents, one balding with grey hair, the other with dark hair and both between 5'7" and 5'9". They declined to comment if they knew the regulations on the river.