gary is that a guitar string by any chance 
No, it's leader wire used for fishing, kinda like the natives might have been using. If you think it is too thin then cut yourself a piece of 7x19 wire rope, it naturally coils itself up too.
gl
Available from all good fishing tackle stores on gardner Island, honestly.
Yes, most likely it was. This is common stuff and has been around forever. Gardner Island is not the moon, people lived there, harvested copra, fished, grew kitchen crops, repaired their boats, etc. Goods were brought in to be sold to the inhabitants, most likely at a "Chinese store," a general store stocking everything needed by the island people including fishing equipment. I get the feeling that some think that Gardner was "the land that time forgot" with primitive natives building stockades to keep out the dinosaurs and King Kong. In fact, it was set up as a money making proposition, people were imported to work there growing coconuts, harvesting them and drying the meat to make copra. Then the schooner would come, buy the copra and, guess what, the workers would get paid for their labors. Where do you think they spent their money? What do you think they purchased? The local store stocked everything that was useful to islanders, pots, pans, bowls, shovels, wheel barrows, nails, hammers, saws, canned food, fish hooks, fishing leader wire, etc, and these goods were brought in on the schooner. I wouldn't be at all surprised, based on what I have seen in many "Chinese stores," that the Gardner store even had some goods that would make good presents for the wife, such as a compact with a mirror, and I'll bet that bits of aluminum, harvested from American bases, also ended up on the store's shelves.
gl