There is a book called 'sailing the farm' that has a lot on seaweeds etc in it...sorry can't remember the author but I guess you can google
Cookery writer, Hugh Fearnley-Whittingstall, in the UK has a lot of stuff on his website
you will need to search the forums
Cruisers handbook of fishing
by Scott Bannerott is excellent for what fish
, shellfish etc are good, how to catch and prepare them
The main problem is that most books
are specific to a particular geography so you may need to look closely at the area you will be sailing. Best of luck...