The Woman Who Survived A Shipwreck, Starvation, And Isolation — The Incredible Story Of Marguerite De La Rocque
Seabird eggs in late spring and early summer are nutritionally substantial and would have been a valuable supplement to meat.
Fish — cod and other species abundant in the Gulf — could potentially be caught from the shore or in shallow water, though this would have required improvised tools and techniques.
And bears.
The accounts consistently mention bears as a food source, and bear meat is nutritionally valuable.
A large bear killed at the right time of year would also have provided a substantial hide for warmth.
The question of how Marguerite learned to exploit these resources effectively is not answered by the historical record.