I think its a northern but I've heard about how young musky and northern look almost the same. It was 18" long and man you should have seen her face as she was reeling it in. I saw it come out from behind a boulder and just stare at the worm. I told my daughter to reel up the slack and when she tightlined it gave the bait a little jerk and the gills flared as the fish attacked. I enjoyed watching it.