I think it can be interpreted as a reflection of how unsatisfied she is with the life she's known. But there's no way out [across] because her true self belongs to a kingdom that has long been dead. Her life as a pirate was insufficient [yielded no fish] for her.I can see this girl's dreams...
Oceans...
Oceans...
Oceans...
Oceans...
Oceans as far as the eye can see.
They are vast seas...
None can swim across them...
They yield no fish to catch...
And of course this leads Ganondorf to describe how hopeless everyone's life is for precisely the same reasons. They're just "fallen leaves on a forgotten pool" with no real purpose or potential. "Your gods destroyed you!"