Here is a version (posted to rec.music.filk by Jim Caldwell) of the tune to Shannon Caldwell's song "Egan, the Harper Who Wasn't", along with the chorus tune Shannon added specifically for "World Without Shrimp"; it is in ABC notation.

There are three sections here: The first (a) is the tune used for the first verse of "Egan" (and is presented with the lyrics to that verse), and the second (b) is the tune used for the other verses of "Egan". Either one is suitable for any of the verses of "World Without Shrimp" (tune a requires a tiny bit of modification). Section c is the "World Without Shrimp" chorus tune.

Once again, many thanks to Shannon, who is the sole author and composer of "Egan, the Harper Who Wasn't" and the added chorus tune.