Difference btwn trout & salmon?

[Major problem]

Can anyone point me to an online resource for a definative description of landlocked salmon and winter trout?

My buddy caught a fish during the derby and we asked for a second opinion from many people who said it was definately a trout. The weigh-in people said it wasn't a rainbow. The fish had some color but from what we've been told there are no brown trout in Winni. The pic I have shows a forked tail but when laid flat it was square.

I've been fishing Winni for many years and every winter we've cut the line on many a "salmon". There's always a debate about species ID.

The fishing laws extract and derby brochure don't seem to capture the subtle differences.

From what I've seen, there are many thousands of seasoned ice fisherman/gals that also get confused. The penalties for taking a salmon through the ice are very harsh. Everyone is supposed to know the difference just from seeing the head of the fish in a two foot hole on a cloudy day.