What caused the collapse of the Peruvian anchovy industry?

Originally landed on: A Brief Introduction of El Niño

Fisheries management is about calculating exactly how much fish can be harvested in a given fishery without killing all of the fish. If all fish are caught, none are left to reproduce and make more fish to catch later. Fisheries ecology is about making models that take into account everything about the life cycle of the fish, from early life history to diet to habitat use to reproductive patterns - then figuring out fishing seasons, fishing gear, size and catch limits, etc. that will allow everyone to do some fishing while harming the overall population the least.

The fisheries model for the Peruvian anchovy fishery was originally devised in the 1950s, before the nature of El Niño was well-known. It did not take into account the effects El Niño had on the fish, which was that the population was smaller. Fishermen therefore fished for them at the same harvest limits as normal years - which, during an El Niño year, is not a sustainable rate.

There was a strong El Niño in 1972. The fishery collapsed shortly after that.

Learn more about the basics of El Niño, La Niña, and the Southern Oscillation (ENSO for short), from both a historical and a modern scientific perspective in this introductory article.