A potential problem with a fishing ban:
If people eat less fished seafood, they have to eat more of something else to get enough calories. More fish-farm capacity would have to come online. Or less non-fish food would have to be wasted or more would have to be produced.
One solution is cutting back on meat production- cattle, poultry, etc.- because those are the most inefficient uses of land for food production. If we could stop a lot of meat production, we could produce a lot more vegetable crops on the same land. But then say US industry produces less meat- foreign industry will be tempted to pick up the market, maybe entailing more deforestation to get more land for ranching within their own borders. So just requiring American ranches to produce less meat wouldn’t be the whole solution. We’d actually have to tax or ration meat, and maybe make treaties on protecting forests or on beef and poultry. So other solutions that might have to be included or might even turn out to be more important are vertical farming and artificial islands as a way to increase farmland. Currently, very few water-saving innovations that have been developed are being widely or universally used- as a couple examples, new waterless urinals and all sorts of home appliances that use much less water are on the way or are already on the market, but just haven’t caught on yet. With this potential, it’s possible that for some areas increased farming won’t have to mean increased water scarcity.
Perhaps also, governments need to start doing public relations for vegetarian foods. Morningstar foods are pretty good-tasting vegetarian and vegan meat substitutes, so similar products might be good to start the public on vegetarianism with.
If the whole nation could accept recycling after no more than two or three decades, than it seems like it should be about as easy to get everybody to become at least a little more vegetarian. It’s not really hard to understand how bad meat is for the environment, as far as carbon dioxide, global warming and deforestation- it’s probably been explained in a bunch of popular magazines and on a bunch of TV shows by now (I think I’ve already seen in both Wired and Popular Science). And the connections between the meat industry and the problems of land scarcity, overfishing, etc., can be explained in media venues that are aimed at a smarter audience. This will help win them over and make them more confident in increased vegetarianism when they speak to less intelligent people about it.