Watch the counts at The Dalles AND find out when the nets are in. There is typically an early shot of fish sometime in July and it is fast and furious then goes dead until maybe Mid-August and then gets more consistent. 2000-3000 a day over the dam for an extended period of time is good news, at times there will be over 10000 a day for a little bit.
If the Columbia gets real warm like it did last year the fish will lock up between the dams and seemingly disappear until it cools down.
If there is a good variance in temp between the Deschutes and Columbia, even 5 degreesF I would park the darn boat and walk up and chuck spinners because almost every fish going by that feels the cooler waters of the "D" will pull in there for a rest. Not uncommon for Idaho and WA fish to be caught many miles up, they even get some in the trap at Pelton. In my many years fishing there I've noticed the hatchery fish caught early in the season are roughly only half carrying Deschutes clips. Just for kicks I call up Steve Pribyl at The Dalles ODFW and write down the Deschutes clips for each season so I can see how many I catch are bound for somewhere else, adds a bit of fun to the day.
Last year was incredible, half the fish were wild, typical Deschutes fish, five pounders and even smaller but very HOT, especially on fly gear.
I couldn't tell you about Sherar's because that's not my preferred method of fishing but I do pay attention to the fish weir/trap and the daily totals of fish going by. Any fish that uses the little fish ladder to get over the Falls is tagged and judging from my ratio of tagged to untagged fish caught upstream from the falls I'd say only one in 6 or 7 fish actually use the ladder. So take the steelhead totals for the day and multiply it by that and I think you'll get a fair estimate of how many fish are upstream.
Anyhow, a long ramble. Just goes to show I'm licking my chops for that first viscious tug on my fly..........(not that one, the one with the hook.....

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