"La Petite Fille de la mer" is the second track from the Vangelis' album "L'Apocalypse des animaux", which is a soundtrack album composed to accompany a documentary series about the animal kingdom directed by Frédéric Rossif, first broadcast on French TV in 1970.
As such then, this is one of Vangelis' earliest works, recorded whilst still a member of progressive rock band Aphrodite's Child.