Timeline of the Irish Potato Famine 1845-1851
The first thing that I'd say is that it could have been geographical. The famine was very widespread, but not completely so. It may have been that your ancestors lived in one of the lucky pockets of Ireland which largely escaped the famine.
They may also have been rich. Only the potato crops were blighted, there was other food in Eire at the time. The majority of it was being sent to England, under a military escort; but the wealthy Irish (usually Protestant Anglo-Irish) could afford to eat.
Otherwise, you are looking at a massive struggle. Your people could have been kept barely alive under the work programs, or through charitable organizations. They might have managed to keep hold of their fishing equipment and eaten fish. They could have used wild, edible plants. There are a myriad of individual stories of survival here, but none are pleasant to explore.
It is a very dark time in Ireland's history.
JoHarrington, Sep 2, 2012