Rob Stewart first presented to UK cinemagoers as the tanned, buff Canadian Cousteau figure fronting Sharkwater, a documentary that hymned the sleek beauty of the selachimorphia genus and sought to defend its animal subjects against a number of threats: what was defined as the "Shark Week propaganda" coming out of Hollywood, the predations of shark fin soup lovers, and the wider indifference of man, busily pumping plastic and other toxins into the oceans. Now Stewart returns with a sequel, Sharkwater Extinction, which shapes up as a mystery, as if the real killer had been missed by the first movie. It opens, indeed, with a stark fact: 150 million sharks die in international waters each year, apparently, but scientists can only account for around 70 million of these deaths. There's something fishy going on, in other words, and Stewart's investigations in the course of the movie turn up some answers, while heading towards a development this viewer, for one, wasn't expecting, and which this otherwise very watchable film doesn't entirely know how to handle.
For much of its running time, Extinction exudes the appeal of noir in open air, as a blithe detective in sleeveless T-shirts follows this bloodtrail down dingy backstreets in sunny locations, accompanied by invariably photogenic female assistants. We begin in Costa Rica, where finning (the process of slaying sharks for the riches contained in their extremities) has notionally been outlawed, but where Stewart's crew uncover a series of under-the-counter deals that opened up the docks to all kinds of nefarious, shark-harming activity; chased out of town, Stewart moves onto the Bahamas (nice work if you can get it); to Panama, a birthing hotspot where toxic meat is passed off as cheap eats in less than scrupulous eateries (lifehack: avoid the "rock salmon"); to Cabo Verde, a geographical loophole facilitating the import and export of boatloads of fins; and finally back to the U.S., where Stewart's inquiries see him being shot at by aggrieved trawlermen. It's one of those digest-docs that packs in and hops around a lot, but it quickly identifies a recurring suspect in deregulated capitalism, all but given up when a hunter wearing a sharktooth necklace declares "Show me the money".
For all the ugly and underhand behaviour Extinction uncovers, it remains a film of considerable, at times shimmering beauty. Early on, Stewart states his aim as being "to make people fall a little bit in love with" his sharp-toothed subject, and thereby encourage us to look out for sharks as we traditionally have lions, elephants and pandas. The underwater photography he commissions is properly mollifying, bringing us closer than ever to the immense grace of these creatures, and vividly illustrating their ability to co-exist peaceably with other species. When Stewart, mid-dive, extends a gloveless hand to one such creature, as if he were in a petting zoo rather than the middle of the deep blue sea, he may as well be holding an olive branch. (The film entire stands as testament to the ways lightweight digital cameras have brought a new immediacy to reportage, on both land and sea: the tech carries Stewart and viewers closer to these sharks than Cousteau ever got, and - in its surveillance application - to those shark-corpses being flung into the back of vans to be sold onto restaurants.)
It transpires, however, that these jaws were the least of Stewart's worries. It's jolting when voices other than our established narrator's flood the soundtrack some way into the film, and more than a little disconcerting when the camera suddenly lingers on our host as he makes preparations for what, in the course of events, looks set to be a routine dive. These were editorial choices imposed on Extinction during post-production, for Stewart drowned during that dive in January 2017. (The pre-dive close-ups correlate to those shots in Asif Kapadia's Senna of the racing driver ahead of his final green-for-go; it's footage transformed by hindsight.) The shock occasioned is at least partly down to the fact that, for the preceding hour-and-a-bit, Stewart has been so present, so visibly alive (as folk on camera tend to be), and the development seems to catch the film offguard, as it does us; suddenly rudderless, it stitches together a tribute montage before prematurely fading to black. (Stewart retains the director's credit; a wrongful-death lawsuit is currently being argued over.) Clearly, this isn't the ending anybody associated with this project wanted, yet by folding in these tragic events with a notable sensitivity, editor Nick Hector ensures Sharkwater Extinction emerges as a thematic continuation of Stewart's conservation work. It's a reminder that all life is precious and fragile, and that we'll miss it when it's gone.
Sharkwater Extinction opens in selected cinemas from tomorrow.