COJIMAR, Cuba (AP) — Ernest Hemingway’s love of the sea and eye for detail have scientists hoping that a visit to Cuba by the author’s grandsons will open access to his fishing logs, which may be a treasure trove of information about the state of deep-water species before they were diminished by overfishing.

Patrick and John Hemingway launched a five-day mission to the island Monday intent on helping improve U.S.-Cuba ties and gaining permission for researchers to study the aging documents.