tldr: please make fishing an order
Just about everyone who's played dwarf fortress for any length of time knows how ridiculous and frustrating fishing currently is. Dwarves with the labor enabled and access to water will immediately begin spending inordinate amounts of their time fishing, regardless of whether the facilities to handle the cleaning of their spoils exists - resulting more often than not in a mountain of rotten fish that is of no use to anybody, and if the facilities are present, an additional mountain of shells that will probably decay before being used [but that's another matter], slowing down the game and taking up a tremendous amount of stockpile space.
If a player would rather not have this problem, they have to go through each individual dwarf and new migrant to turn the labor off. Sure, they could always use dfhack, but strictly-vanilla players are out of luck - and besides, the flaws of the UI are a much more fundamental problem for another time and not really what is at issue here.
But there is another way. One that would solve all of these problems. A system already in the game, just waiting for the day of its implemention with regards to the fishing labor.
Ladies, Gentlemen, Distinguished watchers of bay12 - I present to you: the orders/workshops menu!
Alongside such trusty options as auto weave thread (l), auto collect webs (w) and auto prepare fish (f), i humbly present to you the idea that the act of fishing itself be added - each fishery having a single "fish" slot, as is the case with looms having one "collect webs" slot; the more fisheries you have, the more automatic fishing jobs are produced.
This would allow players to globally disable fishing in a mere three keys (specifically, o-w-f; i propose the current fishery order be realigned to o-w-p, for "prepare raw fish") as well as curb the dwarves' ravenous lust for bodies of water. Due to the current state of food, most forts will only ever need a single fisher; those that desire more in the short-term could simply que up more fish orders at the fishery, or create more workshops if they find themselves in need of a greater number in the long-term. And should a player never feel the want of engaging in the fishing industry, they might simply never construct a fishery in the first place!
"Ah!" you might cry out in despair as you notice my wording. "If, as you point out, food mechanics might one day be changed so as to make food production harder, then what should be the point of such a change?" Well, dear commentator, i propose the following: allowing the amount of auto-qued jobs to be changed; or, for a solution closer to the functionality we already have, using the manager to que up more fishing jobs.
In any case, having fishing tied to fisheries rather than to the whimsy of dwarves would surely be a boon to any player within the foreseeable future.