I've no information on the age of the tune. It's in Volume 1 of Marjorie
Kennedy-Frazer's Songs of the Hebrides (title:Taladh Criosda) which gives
a translationof an old story associated with the tune plus a setof verses
which had been collected byFr Allan MacDonald inEriskay. The tune (not the
words) isgenerally associated with Eigg, rather than Eriskay, although MKS
noted it inEriskay. A footnote inthe MKS book says the melody was heard by
Chopin as a Northen sailor'ssong.
PS: MKS vol1 was published in 1909, she did her Eriskay collecting stint
in 1905, Taladh Criosda was published separately (single song sheet) in
1906. That'sprobably earliest publication of the tune, I haven't noticed
it in any earlier collection anyway. But I imagine the tune is much older.