Movie premieres are usually held in New York or Los Angeles. But not “Mission Blue,” the Netflix documentary by Fisher Stevens and Bob Nixon about renowned oceanographer-marine biologist-environmentalist Sylvia Earle. Appropriately, the movie screened this week on Martha’s Vineyard for a large crowd at Menemsha Beach that was splayed on blankets and beach chairs. Among those watching “Mission Blue” as waves lapped the shoreline were Earle, Nixon (whose mother is “All My Children” creator Agnes Nixon), actress-model Lauren Hutton, several members of the Kennedy clan, including Robert F. Kennedy’s son Max, actresses Marisa Tomei and Jodie Foster, the island’s de facto fishing guide to the stars Buddy Vanderhoop, and Eric Gordon, who financed the film. “Mission Blue” will be released on Netflix Aug. 15.