The Benguela region, off the coast of Namibia, is a shadow of its former self. In the first half of the 20th century, it was one of the world’s most productive ocean areas and supported a thriving fishing community. Today, the plentiful stocks of sardines and anchovies, and the industries that overexploited them, are gone. The water is choked of oxygen and swarming with jellyfish. Plumes of toxic gas frequently erupt from the ocean floor. But one fish, the bearded goby, is positively thriving in this inhospitable ecosystem. It’s a critical link in a food web that’s on the verge of collapse.

For every tonne of fish currently swimming in the Benguela waters, there are more than three tonnes of