The PK shrimp will only feed the smaller fish, the threadfins will have to be restocked every year, and I don't know of any place to get them up here in the northern part of the state.
Best bet is to take out as many LMB as possible. It takes 10# of forage fish (that's eaten) to put 1# on ONE LMB. How many pounds of forage fish will it take to turn the LMB around without removing mouths to feed?