Sockeyes are plankton feeders.
They MAY strike a fly if defending a redd, but I've never seen one pursue a fly as as food/prey. Maybe I haven't fished enough in clear water...
Others claim differently - and they may be right.
Me - I've long since gone to dip-netting or using a gill-net... Too bad TNT ain't legal.
But I still have the rod-fishing gear just in case I ever get to waste so much time again... I'm getting old, ya know- not that much time left to waste.