Correct me if I am wrong here but there are already chinook, presumably summer run steelhead and coho in the somass river system right now because chinooks are turning up in the first nation gill nets in the river already and I would easily assume in the commercial nets aswell and DFO has posted on their commercial opening bulletins that commercial fishing should try and avoid certain area's at certain times for migrating coho (I highly doubt they care) but they are aware they are in the canal already aswell.
If they close the gates on the stamp falls wouldn't that stop other species from reaching their spawning destinations, chinook and coho returns havn't been all that spectacular especially chinook in the past few years (20,000 - 25,000 spawners natural/hatchery).
So what I am trying to say is wouldn't other species get tired and eventually die from not being able to get threw the fish ladder since it's probably the hardest part of the entire river to pass threw?