In many of our fisheries lures are required to be single hooks, or maybe even barbless. However lure makers keep making lures with treble hooks.
So to be compliant with the regulations you have to modify your lure.
Generally speaking siwash hooks are a good to use when replacing treble hooks. You should follow the lure manufacturer’s recommendation for what size hook to use. This information can be on the lure’s packaging or the manufacturer’s web site.
If that information isn’t available then a good rule of thumb is to select a single hook that has a gap that is 50% larger than the gap on the treble hook. For more information about that please see here.
Once a replacement hook is selected then remove the treble hooks by working its way out of the split ring.
Optionally you may put a small swivel on the split ring, to allow the hook to spin freely.
Lastly crimp the hook eye around the swivel/split ring.
The result should wind up looking like this.