Sardine (Sardinops spp.) and anchovy (Engraulis spp.) populations around the world have exhibited extreme fluctuations, often varying a thousandfold in abundance from one decade to the next, accompanied by economic boom-and-bust cycles that have become legendary. In nearly every case, fortunes are made during times of abundance, not only by the fishing and processing industries, but also by secondary industries such as poultry ranching and fish rearing—industries made possible by convenient large quantities of inexpensive, high-protein animal food. Yet the prosperity typically lasts for little more than a decade, and suddenly the fish stocks mysteriously disappear. In some cases, alternative fisheries are eventually developed. However, in nearly every instance of stock collapse, the social and economic damage is severe. Once prosperous fishing communities become ghost towns: processing plants are boarded up, equipment is sold, and large fleets of fishing vessels slowly rust away.