They aren't very interesting, I'm afraid; except perhaps to seals. Ewan MacVicar posted them here some years ago, when someone was wanting information about a recording by Mary McLaughlin which included the song (rather eccentrically spelled Yundah:

RE: Yundah: Hebridean Selkie chant???

I may as well quote them again, and add the tune.

THE SEAL-WOMAN'S SEA-JOY

Ionn da ionn do
Ionn da od-ar da.
Ionn da ionn do
Ionn da od-ar da.
Hi-o-dan dao od-ar da.

As quoted in Songs of the Hebrides, Kenneth MacLeod and Marjorie Kennedy-Fraser, vol.II. (But here re-quoted from David Thomson, The People of the Sea, 1954).

X:1
T:The Seal-Woman's Sea-Joy.
B:Songs of the Hebrides vol.II
Z:Marjorie Kennedy-Fraser
L:1/8
Q:1/4=120
M:3/4
K:C
|: (A6 | D6)| A6 | G6 | {d}A6 | D6 |
w:Ionn da ionn do Ionn da
C2 C4 | D6 :| {A}(G2 F2) G2 | A6 || C2 C4 | C6 |]
w:od-ar da. Hi-o-dan dao od-ar da.

I don't know the original source; something else to try to remember to check at the library. Kenneth MacLeod added the following (rather cutesy) account of the background:

"The Isleman in whom goodness is stronger than love, finding the sealwoman bathing in the creek, will let her go back to her own natural element: the Islesman in whom love is stronger than goodness cunningly hides her skin, and weds her on the third night after he has found her.

The sealwoman was hot and tired baking the bread and making the churn against her husband's return from the hunting-hill. "Ochon, the burning of me", thought she, "what would I not give for a dive and a dip into the beauteous coolness of the cool sea-water!" On the very heel of her words, who rushed in but her wee laddie, his two eyes aglow. "O mother, mother," cried he, "is not this the strange thing that I have found in the old barley-kist, a thing softer than mist to my touch!" And if she looked, and look she did, this strange thing, softer than mist, was it not her own skin! Quickly, deftly, the sealwoman, tired and hot, put it on, and taking the straight track to the shore, it was nought for her then but a dip down and a keek up, all evening long, in the beauteous coolness of the cool sea-water. "Wee laddie of my heart," said she, ere night came upon her, "when thou and thy father will be in want, thou wilt set thy net off this rock, and thy mother will throw into it the choice fish that will make a laddie grow, and a man pleased with himself."

And the sealwoman, with a dip down and a keek up, went on lilting her sea-joy in the cool sea-water."

-Kenneth MacLeod, The Road to the Isles, 1927.