My younger daughter lives in the country where they had a massive feral cat problem. She and her husband took it upon themselves to live-trap all the cats (over a dozen at last count) and take them to a local vet who spayed and neutered them for free They then returned them to the point where they were captured. This does two things: it prevents them from reproducing and, because they are territorial, keeps new cats from moving in. BTW, since they were feral there wasn't a lot of chance they'd be "tamed" enough for pets so this was the best solution. That being said my soft-headed SIL did keep a couple of kittens.
Also, one of the problems with having an ordinance to control cats is that cats can't read.