Patrick Frater Asia Bureau Chief “Meg 2: The Trench” serves up a school of prehistoric fish that chew up the seas, a snapping pack of imaginary hybrid dinosaurs that wreak havoc on land and a surprising cinema business model — the Chinese-controlled franchise intended for a global audience. And while early reviews are predictably mixed, the film’s box office debut looks promising. In China, on Friday, it bit off a $19.5 million first day and enjoyed a 50% market share.