I vaguely recall one of the "deep waters" fish being unintentionally fished up by Stella (Gen8) while Hiroki was out fishing on his canoe.
Stella was over fishing to the left of the Journey's End lot ("left" as you face the lot's front entrance).
Sadly, I don't remember which "deep sea" fish it was exactly, but you might try that sport.
P.S. I just went back and re-read several Gen8 updates. It might have been the Swordfish (not the Gold Mahimahi) that they caught without the canoe.
Oooh, Dirk got his high cheekbones from Papa Clement, right?
Davina is so adorable in her PlantSim outfit with the little apron!
Great progress on your collections and aspirations, Watcher!