The turning point for polar and marine scientist Angela Köhler came in 2005, when she attended a demonstration on caviar production in the Caspian Sea. Bringing out a two-metre female sturgeon in front of 150 conference guests, the caviar master beat the fish on the head to death before cutting its belly open. “The masters suddenly became extremely nervous,” she recalls. “They went on to say that the eggs were too close to spawning and so they couldn’t use them as caviar. They discarded the entire fish and began the process again with a new one.” The brutality of the...