What to do with the uninsulated ground wire with fishfinder

[Gill-T]

I spent approx. 40 hours on boat projects this weekend, and while cleaning up and organizing my boat wires, I realized I did not have the bare ground wire on my Lowrance fishfinder attached to anything. What should I do with this wire? The wire is too short to run to my behind dash mounts. Do I splice in and run it back to the engine ground or can I just wrap it around any present mounting screws?