The city of Cairo straddles the river Nile with a number of small islands in between. While sitting in traffic on a bridge in central Cairo, it is not uncommon to see a family of fishermen on their boat in the middle of the river. "There are no fish like there were before," says Um Mohamed, 36, who works alongside her husband. "It's not enough to live on. It used to be enough, before we didn't need anything from anyone."