Depends how long you're in Scotland. From his likes I'd suggest a trip to Islay as all 8 distilleries there run tours and there's some good beach and boat fishing.
If it's river fishing then I'd recommend visiting Speyside where nearly all distilleries run tours. Athough 90% of the fishing's in that area's for trout and salmon, costs a lot of money for licences, there is a little coarse fishing available which is a bit cheaper to do. Have a look at the hotels in the area as they may also be able to arrange for the fishing as well as distillery visits.