Since we're gobbling up fish faster than they can spawn, aquaculture has had to pick up the slack. Fish farming produces about half of the fish we eat -- the rest comes from increasingly depleted fisheries. So it's likely that if you want to keep fish as a regular part of your future diet, you'll have to rely more and more on the farmed variety. Unfortunately, farming doesn't always produce the healthiest, tastiest animals.
To keep fish accessible and safe from rough weather, most farming operations are close to shore. The resulting combination of poor water circulation plus tight quarters can equal disease or heavy antibiotic loads to prevent it. Deep water cages offer more circulation (and the potential to introduce a little natural food into the fishes' diet), but due to their inaccessibility, they're not particularly convenient. Could robots do the work for us?
We're already part-way there according to National Geographic News: Cliff Goudey of MIT is building self-guided operations that equip Aquapod cages with propellers. While the Aquapods are still tethered to steering controls on a surface vessel, it's likely that automated cages will eventually be left to their own devices. The future automated fish farmers would move like a wild school and harness their own solar or wave power along the way.
Another odd aquaculture concept is a bit more Pavlovian than robotic: It involves training fish to gather when they hear a specific sound. Basically, caged fish can leave their confines and forage for the day if they've been trained to return when a "dinner bell" sounds. It worked with black sea bass in an experiment in Buzzards Bay, Mass., until predator bluefish caught on, making the connection between the bass' dinner bell and a bass dinner for themselves.