where on mull?
you'll need to be on the west or north west coast for the mackeral from the shore, but there should be one or 2 about now. Calgary bay might be worth while. park in the carpark and then follow the track on the north side of the bay to the rock edges on the open water, bit of a walk though, reasonably deep, and if there's no mackeral, you're sure of pollack coalies and wrasse
not heard of tope from the shore up there though
Tackle and Books in tobermory run boat trips for 15 quid, which should get you out to the mackie and some reasonable pollack marks