Looks like they have expanded their habitat.
From the NH fish & Game
Habitat: Rock bass are found in the shallow margins of lakes, ponds, and larger rivers where they usually prefer rocky or substrate mixed with areas of sand and gravel.
Fished several humps in the broads 25-40' deep using a dropshot rig with a 4" worm. Caught Rock bass/Redeye 6-9"s or same size Smallmouth on every cast.
I would say they are competeing with the Bass, Trout and Salmon if they are on the Smelt and Perch fry.