Anchovies prefer the warmer waters around the world, where they swim in massive schools. Anchovy production can vary widely from year to year. The fish can appear in large schools for decades and disappear the next year, and then reappear the year after that. For example, the U.S. harvested 48,000 metric tons in 1982 and 6,000 in 1992. In 1993 the anchovies reappeared in vast quantities.

"In recent years, scientists have become aware of a particular climatic pattern that occurs between one and ten year time scales. Known as ENSO, (the El Niño Southern Oscillation), this climate phenomenon -- an interannual variation of atmospheric and oceanic conditions in the equatorial Pacific -- has been described by climatologists as the largest single source of interannual climate variability on a global scale. . . . The classic example of ENSO's climatic clout is the 1982-83 El Niño event which had enormous economic impact on the fishing industries in Ecuador and Peru due to failed anchovy harvest that occurred when sardines unexpectedly migrated south into Chilean waters." For more on this, see the report "Climate Science: Investigating Climatic and Environmental Processes," published by the National Geophysical Data Center.

Since the warming often peaked in December, in the 1890s it was dubbed "El Niño," in honor of a previous December visitor, the infant Jesus. For more, see El Niño Rules!

Nature, not anglers, killed off bay’s great sardine runs, scientists report
Santa Cruz Sentinel staff and wire reports
January 10, 2003

SANTA CRUZ — It may be worldwide weather patterns — and not overzealous fishermen — that are responsible for the disappearance of sardines from local waters over the past century.

That’s the suggestion of a new report being released today in the journal Science, and it challenges the conventional wisdom that mankind had a big hand in killing off the Monterey Bay’s once plentiful sardine runs.

The research team reports that for 25 years or so, the ocean waters tend to be a bit warmer than average, which is best for sardines to thrive.

Then things cool somewhat, and the scale tilts toward the little anchovy for about another quarter century.

In fact, anchovies and sardines appear to take turns being plentiful across the Pacific Ocean.

If Francisco P. Chavez and his team of researchers at Monterey Bay Aquarium Research Center in Moss Landing are right, anchovies will be on the ascent for the next few decades, good news for lovers of Caesar salad, pizza, pasta and other foods that are often perked up with little fish.