In flat netting, a Stop Bead is required to hold the initial row in place on the thread and also helps with keeping the correct tension as the work grows.
When working in a round, you don’t necessarily need to use a stop bead. If you struggle with keeping your tension uniform you can optionally use a stop bead for circular or tubular work as well.
Check out this Post if you need a refresher or have not used a stop bead before.