I'll
bite.Are we using this as a practical real-world example and not just an abstract logic experiment?
If so, then barter economy would come into play. Now, you're bartering with perishables here so there's really no use in overproducing ("stockpiling") bread or fish.
We're to assume that all three people are looking for balanced diets, or would rather not eat just bread/fish, so both producers trade with each other for the other's product.
If a machine comes in that can produce fish or bread more efficiently than its human equivalent, then the land owner that now controls the means of production no longer needs the other two producers to pay him anything.
He can continue to take fish and bread from them, but it would just spoil uneaten in his stockpile. So, these two producers must now find something of greater value than the now devalued (see: supply shocked) fish and bread to pay the rent, if we assume the land owner is purely business-minded and has no care for preserving others professions, or face being evicted.
However, since this is a barter economy this means its also likely a libertarian system. This means the two producers would both benefit greatly from "removing" the land owner from this equation and continuing their production of an outdated good. Both now have monopolies for their goods and are well off forever to the end of time.