commercial fishing is about the only control for gar,carp,buffalo,drum etc.
when my uncle net fished rough river many years back with gill nets all those fish were sold to be eat even gar. if you grind them up and can them in a pressure cooker,like grandma,them make salmon like patties carp buffalo etc are actually pretty good,the pressure cooking dissolve the bones.
just don't put tails and fins and main skeleton in it..