I voted for the most obvious Nets. , but the one thing I think is the real problem is predation. I think you have to start at the beginning , when and where the salmon and steehead start thier lives , Mergansers, Commerants, Herons, River Otters, these critters take a tremendous amout of the fry/smolts before they can even start thier next gauntlet in life, which would be trying to avoid getting eaten by seals, sea lions, other salt water birds , salt water otters and finally NETS. To give you a few examples Four years ago Reider ponds holding ponds had no netting over the ponds , there was 305,000 steelhead in each ,summer runs in one winter runs in the other, when the ponds were drained down( I was there) there was 44,000 left in one and 140,000 left in the other! that summer there was nets put over the ponds and the total loss from both ponds was under a thousand! Big differance! the year before we watched 5 otters eat and terrorize the smolts to the point when they were done eating they relentlessly chase the smolts to the point of exhaustion in the ponds, we watched the same thing happen in the river, A Merganser eats about 20-25 fish a day ,has between 5-18 young .-do the math it dosen't take long to figure out where the fish went PREDITORS think about it protect your young. Oh yeah 'I forgot to mention all the fisherman I saw using eggs and ripping the hooks out of the few remaining smolts as if they were pissed that the "Little *******s" had the nerve to bite there eggs when they were fishing for real steelhead , and of course you know that after having there thier heads almost ripped off ,planed across the water , hooks torned out of thier stomach and thrown back they LIVED!! NOT...........