Doing the selkie thing.

Doing the selkie thing.

John Sayles’s 1994 The Secret of Roan Inish introduced filmgoers to selkies, mermaid-like creatures from Celtic mythology who live as humans on land and as seals in the sea (15 years later, Colin Farrell fell in love with one in Neil Jordan’s Ondine). Tomm Moore’s handcrafted, Oscar-nominated animated feature Song of the Sea centers on Ben (David Rawle, the hilarious kid from Moone Boy) and his younger sister, Saoirse, who live with their widowed lighthouse-keeper father, Conor (national treasure Brendan Gleeson)…