I've always understood it as follows: Unless specifically noted (examples are Catch and Release Bass on Susqy/Juniata or the Approved Trout Waters, the 'fail to immediately return unharmed' language applies.
Technically, that means one could target Bass, Walleye, or Musky 'on beds', as long as they return them unharmed, since the same blanket prohibition doesn't exist.
As a sporstman who appreciates the resource and wants to see it thrive, I've never considered targeting species out of season. Originally from Tionesta area, and fished the Outlet of the Dam to River extensively. Would often catch Musky or Bass when out of season while targeting Crappie or Perch. Just released unharmed. As recently as last May, while fishing Tionesta Ck. between Outlet and River for Trout w/ Panther Martin, inadvertently pulled 3 HOG Smallies off of beds. Released unharmed, hoping that they found their way back. But wasn't targeting them, was using a Trout spinner. If had been using a 4" Rapala, hard to argue you're going after a 12" stocked Brown Trout . . . although, technically wouldn't be 'illegal' as long as it was released unharmed, at least as I read the inland waters regs.