You can get sushi at football games in Texas and in Lodz, Poland. In China, Russia and Brazil, diners have developed a taste for it, too. One estimate, cited in Mark Hall’s documentary “Sushi: The Global Catch,” has China adding 50 million sushi eaters in the next few years.

That may be good news for sushi as an international cuisine, but it’s bad news for some fish.

Hall’s film has both a story and a mission. The story involves how sushi went from being a local specialty in Japan, where some chefs still undergo rigorous training — it takes two years to master rice making alone — to a food available seemingly everywhere and in every way. (Consider the Sushi Popper, a roll packaged like ice-cream pushups.)

That story leads to the mission: The abundance of new consumers has meant the dramatic depletion of some species, especially the bluefin tuna, the Porsche of the seas. (It’s fast and expensive.)

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As storytelling, “The Global Catch” often falls short. It has too much to cover to be comprehensive and can seem a bit random.

As a consciousness raiser, the film fares much better. What happens if bluefin tuna, a vital predator, disappears? It could be catastrophic for the ocean ecosystem, the film argues, and government regulations have proved ineffective in the face of rising demand.

The film’s arguments about sustainability are convincing and hard to shake. And the movie suggests you, the sushi eater, can help: Crave it and enjoy it, but eat sushi responsibly.