I gave up. I couldn't find any big fish, so I lost all hope of cleaning the mermaid's scribbles off my sea chart. I headed home and left my sister to her fate. That was until I accidentally blew up half a cliff and found a giant fish behind it. He agreed to wash off the scribbles, but we forgot my sea chart is paper. It melted. Big Fish did tell me of a place to get a new one though, so that's ok.