> what if you did go into the rant
*tee-hee* Okay! It will be beneficial for my own purposes to have all the ideas in one post, too. So, the gist of ot is as follows:
Great Sea is not the only sea in the world. The ocean goes on outside of the game's map, Link is just arbitrarily stopped by KoRL at the borders. We know of at least the World of the Ocean King — no matter if Phantom Hourglass takes place in the alternate dimension or not, the waters Tetra and her crew sail are implied to be outside of the Great Sea proper. Even in Wind Waker's text, there's some evidence to there being other countries that have commerce with the Great Sea denizens, i.e. Zunari and the Goron merchants not being from around here.
All the major habitable zones of the Great Sea are located either next to its border (Outset, Forsaken Fortress) or within one square radius of it (Windfall, Dragon Roost, Forest Haven, formerly Greatfish). The center of the map forms a dead zone, with the exception of the Private Oasis (not so much of a populated place, even including the basement) and Tingle Island (which, let's be real, shouldn't count).
There's evidence of both Great Sea being fishless and of Great Sea peoples going fishing at least sometimes, as discussed above. Except these two facts don't have to be contradictory, because:
What if they fish outside of the Great Sea? This would explain the proximity of the major population centers to the borders, as it's easier to transport the haul back home that way. One of the flags from the trading sequence, the Big Catch Flag, is made for "a festival in which fishermen hope for a good catch", yet "was made by a fisherman from a foreign land" — so there are fish in this world somewhere.
Okay, but there are two problems with the idea of them fishing outside of the Great Sea. One: Link seemingly has to be taught how to fish in Phantom Hourglass, despite coming from a fishing village, and Orca is a former fisherman — why doesn't anyone else from Outset is doing any fishing now? Two: if they have regular access to the outside, why Tetra's departure to seek new lands is treated like such a big deal?
Here's where the theory enters a more headcanon-y territory, but: my idea is that leaving the Great Sea, while possible, is really hard.
In BoTW, Hyrule's border is separated from the out-of-bounds areas by two kinds of barriers: regular invisible walls, but also the thick walls of wind pushing the player inside if they were to clip beyond the first type of walls. What if these wind walls existed in the game world diegetically, placed by gods to protect Hyrule from outside threats? It may sound weird, but BoTW is the game that invented Blood Moons to explain a common videogame mechanic of respawning enemies by an in-universe magic, so it makes this leap of logic a little more plausible. What's more, during the Dark Beast Ganon fight, Zelda even places a barrier of her own around the battlefield.
If the above paragraph is not conclusive, the rest of the series has two more examples of an area being separated by a wall of impenetrable winds, both of which are way more diegetic: Sea of No Return in Oracle of Ages and Isle of Ruins in Phantom Hourglass. They're both happening over the open ocean, too.
Going back to Wind Waker: what if something similar is at play over the Great Sea's border as well? If we assume that it, too, is surrounded by the walls of wind, the following quote from Zunari sounds interesting: "My story is a strange one... I came across cursed seas from a land far away...a land where the blizzards blow violently...heading for this town called Windfall. But dear me! As I traveled, a terrible storm descended and tore my ship to bits...yet mysteriously, only that escaped without so much as a mark on it..." — so he came from the outside, having to cross the border, and got caught up in the storm. Crossing it from the inside out, then, must be just as dangerous; fishing becomes a way riskier endeavour if you're guaranteed to hit a strip of permanent bad weather on your way.
It makes Link's role as the Wind Waker all the more interesting, too. His ability to guide the winds could've been a deciding factor that ensured a safe departure for Tetra and her crew; that would explain his presence on this expedition. Maybe he has to go ahead of them to clear the way beforehand, and this is why he sails separately from them on the boat that used to be KoRL. And after the events of Phantom Hourglass, Link has even more control over the storms via the Cyclone Slate and especially the Regal Necklace, the item that helped to dissipate the hurricane around the Isle of the Dead.
TLDR: the Great Sea is fishless, but there are fish living outside, which you can haul, but you have to get across a wall of winds first, so it's dangerous and therefore is done very rarely.
See also: potential reason behind Great Sea having no fish that doesn't rely on that weird "illusory water" tidbit from Hyrule Historia and maybe there used to be some fish within the Great Sea, but not anymore.
germansingergirl
kianamaiart
snowghoul
turnnoffyourmind
s-u-f-j-a-n-s-t-e-v-e-n-s
yousharknotpass
