Then we get to see dying coral, discussion of acidification, and they even made a stop over to mention deep-ocean methane rising. We finally get to the turtle's destination and watch a turtle drag ashore, and they mention that the beach used to have thousands of turtles, and now only a handful return.
And the real topper: while the narration had shown loggerheads at various points along the way, and spoken as if it was a single turtle rather than a figurative one, it was clear to me that they weren't, since the turtles shown never had a tracker, and because footage was clearly being inserted from the early Mexico filming, identifiable by her companion fish. At the very end, you do find out one loggerhead had been tracked, and made it to the waters just off her birth beach... where she was promptly trawled up and drowned.
I've seen some nature documentaries that were more *deliberately* depressing, of the Silent Spring type, but this had the shell of an ordinary Attenborough-style production, and a fucking bleak heart.
Even the blue whale footage depressed me, because I couldn't help but think of how very few they are, and the pregnant female that was killed a couple of weeks ago by a ship.