I'd say cut it out and replace it with a flat-edged strip. I did this on a couple strips on my Spring Run that were water-stained, it isnt as hard as it sounds. Leave the coves on the strips in the deck, and cut carefully with fine-tooth pull saw. Sand the edges a little if needed, and fit a new strip in place. If it's particularly challenging to fit the new on in one peice, two tapered strips may be easier depending on the situation.

I wouldnt try staining it - but then I'm not very good at staining so I'd have a devil of a time matching the color, and blending it into the rest of the boat.

Another option is to leave it in there, and call it "character" or "intentional" or some other creative thing.