While it's not age of exploration, if you want Age of Sail (specifically the period of 1680-1740), for the starving at sea issue, this article I wrote includes a passage that addresses that: Salt Pork, Ship's Biscuit, and Burgoo: Sea Provisions for Common Sailors and Pirates Part 1
Hi! There have been a few threads on this; check these out to get you started
Were naval explorers (Polynesians, Vikings, Spanish) concerned that they would sail forever without hitting land or did they plan to turn back after a certain amount of time? Did they re-supply while sailing (fishing, collecting rain water)? - /u/jschooltiger cites the lack of fish in the deep ocean
Why didn't ship crews fish when lost? - a discussion thread featuring /u/backgrinder and several others
Were pirates and naval ships around the 18th century known to deep-sea fish on long voyages for food or was the only source whatever could be carried on ship? - /u/b1uepenguin describes fishing by the French Navy in the Pacific