The West Coast sardine population was down 72% since 2006 per a fall assessment—the worst crash since the mid-20th century, and one with far-reaching implications, particularly since the steep decline is expected to continue. One of those implications: Ocean predators that depend on sardines may be starving, the Los Angeles Times reports: Researchers think 1,600 malnourished sea lion pups that washed up onshore in Southern California last year were born to nursing mothers whose milk quality was compromised after they had to turn from fatty sardines to other fish; brown pelicans—which also depend on sardines for food—are also suffering. Neither species can turn to anchovies as an alternative food source, as they normally would, because their numbers are also down.
Fishermen, too, are affected; they're not allowed to catch as many sardines (harvest maximums have been dramatically cut)—and they often can't find any to catch (the LA Times follows one boat that caught zero fish in a 12-hour outing). So what's going on? Sardine populations often experience wild swings, booming when conditions are good and then dropping sharply when conditions shift. After the last bad collapse, which happened after a massive boom in the 1940s, sardine fishing was halted for 18 years beginning in the 1960s, and though the population bounced back in the 1980s, it was never the same. Scientists now, as then, aren't sure how to divide the blame between ocean conditions (the Pacific Decadal Oscillation, a climate cycle, has brought cold, sardine-unfriendly water to the area) and overfishing. Last month, Pew Charitable Trusts warned that dozens of species, including whales, sharks, dolphins, salmon, and tuna, could feel an impact.