check out this website:
https://www.nwp.usace.army.mil/op/fishdata/runsum2004.htm

Click the "Bonneville" link and it will tell you how many shad have crossed the fish ladder.

I fished them with the masses right below Bonneville dam and caught tons of them. It was fun.
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Sometimes it's better to think about everything you say......
than to say everything you think about