I've made partial progress tracking down this tune... one verse and the chorus plus my midi sequence.

Chorus
Whale song, soft and low
Sing a story as gently you go
Whale song, I hear what you say
This may be the last time you're passing this way.

Sing me a song of times that you knew
When the waters were clear and the seabirds they flew
Through a sky that was clear from the sea to the land
Safe from the fear and destruction of man.

I may have found an individual who has the rest of the verses, but he has to scour his archives to look. In the meantime hum along or make up your own verses. Nice tune, to be sure!