Don't forget, some regions also have hunting, and that might also require separate rates to account for seasonal migrations and hibernations.
But for balance, we should also vary rates, or at least the base harvest amount, to account for regions that either have only farming/fishing/hunting as a food source, and those that have some combination of the aforementioned. This means that, while it is obvious that a region with a combination of those three should have the advantage in food stability, it should, as compensation, have a lower maximum. That means farming only regions should have the highest maximum food production, with also the highest seasonal variation. Fishing would come in second, but still significantly lower than the farming maximum. I would say that the fishing maximum, which would be as well the minimum since we want this to be stable, would be around the same as farming's summer harvest numbers. Hunting would have the lowest maximum, comparable to about farming's spring numbers. It would have lower variations in all seasons but winter though, when it would drop significantly, like for farming.
In this way, a farming only region is still desirable as it can provide potentially the best harvest for those with good timing and like some risk. Combination regions can be as desirable for stability without making exclusive regions inferior. And in this way fishing and hunting exclusive regions have their own unique flavors as well, though hunting sounds like it will be pretty inferior on its own. It makes sense though, if you think about hunting-exclusive places though.
