I also need to consider that the "upd" could mean they want the latest update or edition. So mentioning checking the latest publications from the authors or the university they're affiliated with could be useful. Maybe suggest reaching out to academic networks or online communities related to marine biology to see if someone has a copy they can share legally.
I need to consider why they can't just find it through a regular search. If it's a specific book, maybe it's out of print or not widely available in PDF. Or perhaps there's a newer edition they're interested in. Alternatively, the user might be in a country where access to certain academic resources is restricted, so they're looking for an alternative way to obtain it. biologia marinha pereira soares gomes pdf upd
Another angle: if it's a specific thesis or paper, looking into Google Scholar or university libraries' online catalogs might help. Sometimes even if not free, you can find summaries or citations that point to where the full text is available. I also need to consider that the "upd"