When herring return each year to Norway’s northern coast, orcas are right on their tail. These clever pods are famous for “carousel feeding,” where they encircle massive schools of herring and herd them into tight, swirling balls, taking turns feeding. Today, herring in these waters are plentiful, but that wasn’t always the case. From the 1960s through the early 1970s, the herring population collapsed due to overfishing. In response, Norway imposed strict catch limits and minimum size laws, and over time, the herring rebounded, helping restore balance to the ecosystem. When fish disappear, orcas, seabirds, and other animals lose a vital food source. Fishermen suffer dwindling catches, coastal economies weaken, and the entire ecosystem becomes unstable. Scientists have also recently discovered that fishing older, experienced herring disrupts their “cultural memory,” the migrational knowledge passed through generations. As a result, many now spawn hundreds of kilometers north, reshapin...