From Horace Beck"s Folklore and the Sea:

Sailors when they die, especially if they die at sea, are said to go to Davy Jones' Locker, which is a euphemism for the devil and hell; but if they are decent chaps they are believed to end up in Fiddler's Green, and undersea paradise not unlike Faeryland ( the words "fiddler" and "green" both are associated with faeries). For that matter, it is not greatly different from the underwater home of the mer and seafolk, thus linking Christian and pre-Christian concerpts together through the picture of Paradise.

While I cannot vouch for Beck's scholarship, this is an interesting interpretation> in the section on songs he includes "The Bonny Shoals of Herring" as a traditional fisherman's song. He personally colleceted it in Dingle, but did not seem to know any more about it.

But I'll see you someday...

Tom