Chaos theory’s potential for fisheries management
© Ralph A. Clevenger/CORBIS
There’s something fishy going on with Pacific sardines. The pint-size swimmers, whose abundance sustained California’s famed Cannery Row for decades, all but disappeared from coastal waters in the 1950s. Numbers remained low until the late 1980s, when enough fish finally reappeared to make commercial harvesting worthwhile again. By then, sardines in the highly productive California Current were carefully managed: Nobody wanted another crash.
Scientists still debate what causes sardine numbers to rise and fall. Overfishing certainly played a part in the collapse; the first catch limits weren’t set until the 1960s, after the population had already declined steeply. Research suggests that a cooling of the eastern Pacific Ocean also played a key role in the 1950s crash. Sardines like warm water, and the eastern Pacific flips between cooler and warmer conditions every few decades. The thinking goes that a cool period starting in the mid-1940s, combined with