I think the cutts would have no problem surviving.
Smelt, sticklebacks, perch, sculpin just to name a few food sources.
I would be surprised if some small sm and lm bass fall victim as well.
The biomass of incests in Lake Wa has to be huge and chironomids hatch year round in western WA.
As CM said, you’d still have salmon coming into the lake out of Issaquah creek.
SF