B-

In a simultaneously frightening and beautiful speech toward the beginning of his one-act play “Suddenly Last Summer” (preserved in Joseph Mankiewicz’s 1959 film version, where it’s delivered by Katharine Hepburn), the character of Mrs. Venable describes the birth of the sea-turtles on the beaches of the Galapagos Islands and the attack on them by ravenous birds as they scramble toward the safety of the ocean. She says that her late son Sebastian, who intently watched the horrifying sight, estimated that only one percent of the newborn turtles made it to the water and survived.

This documentary opens with a similar sequence on the Florida coast as grown loggerhead turtles emerge from the sea to deposit their eggs and the offspring hatch and try to reach safety as birds and crabs feast on most of them. It doesn’t aim for—or achieve—as gruesome an effect as Williams’ haunting description, though, instead using the scene as the introduction to a far more pleasant tale of how one turtle survives, swims around the world and eventually returns to his place of origin to continue the “cycle of life.”

One has to admire the energy of Nick Stringer and cameraman Rory McGuinness, who took two years to assemble the footage stitched together by editors Richard Wilkinson and Sean Barton to portray the quarter-of-a-century journey of a single turtle from Florida across the Atlantic to the Azores and back again. The heroic critter meets up with plenty of other underwater denizens along the way, including most notably sharks and jellyfish. There’s even a potentially fatal encounter with a human being that turns out to be an occasion for kindness rather than cruelty.

That’s obviously an important aspect of the film, which sends with a plea to viewers to join the effort of save the turtles and other sea life endangered by ecological change. The point is also made in Melanie Finn’s narration, spoken soberly by Miranda Richardson.

“Turtle: The Incredible Journey” is the sort of thing that will be more at home on Animal Planet than in a theatrical venue. But of its kind, it’s solid classroom fare.