When float fishing for Mackerel, a trace length of somewhere between 6 – 10 ft is usually about right. Berkley Vanish fluorocarbon line is the ideal choice for the trace (10lb line is ample strength) since it’s virtually invisible underwater, but don’t worry about this too much since Mackerel are far from wary creatures. On a day where Mackerel and Garfish are few and far between, however, it’s definitely worth a try.
For Garfish, shorten the trace to 2 – 4 ft since Garfish generally patrol tighter to the surface.

If you don’t have Mackerel, though, similar sized strips of squid also work well. Fishy baits work best, but Mackerel will also take ragworm.
Another tip to increase your catch rate for Mackerel and Garfish when float fishing is to put a few brightly coloured beads and/or a small spoon just above the baited hook. Then, even if you missed the fish and the bait has been stripped from the hook, you will be in with a chance of a take whilst slowly retrieving your float rig. In this instance, Bling is good.
