Last Friday, Square Enix teased a new "Dramatic RPG" promising the official announcement for today, and indeed the game has now been revealed.
The title is "Kamitsuri" which translates to "God Fishing," and as you can see in the trailer below, fishing is definitely a large part of the game's mechanics.
Of course, if you didn't guess, Kamitsuri will be released for iOS and Android, with pre-registrations already open for the Japanese market here.