The sardine fishing boat Eileen motored slowly through moonlit waters from San Pedro to Santa Catalina Island, its weary-eyed captain growing more desperate as the night wore on. After 12 hours and $1,000 worth of fuel, Corbin Hanson and his crew returned to port without a single fish. 
 
 "Tonight's pretty reflective of how things have been going," Hanson said. "Not very well." 
 
 To blame is the biggest sardine crash in generations, which has made schools of the small, silvery fish a rarity on the West Coast. The decline has prompted steep cuts in the amount fishermen are allowed to catch, and scientists say the effects are probably radiating throughout the ecosystem, starving brown pelicans, sea lions and other predators that rely on the oily, energy-rich fish for food. 
 
 If sardines don't recover soon, experts warn, the West Coast's marine mammals, seabirds and fishermen could suffer for years. 
 
 The reason for the drop is unclear. Sardine populations are famously volatile, but the decline is the steepest since the collapse of the sardine fishery in the mid-20th century. And their numbers are projected to keep sliding. 
 
 One factor is a naturally occurring climate cycle known as the Pacific Decadal Oscillation, which in recent years has brought cold, nutrient-rich water to the West Coast. While those conditions have brought a boom in some species, such as market squid, they have repelled sardines. 
 
 If nature is responsible for the decline, history shows the fish will bounce back when ocean conditions improve. But without a full understanding of the causes, the crash is raising alarm. 
 
 An assessment last fall found the population had dropped 72% since its last peak in 2006. Spawning has taken a dive too. 
 
 In November, federal fishery managers slashed harvest limits by more than two-thirds, but some environmental groups have argued the catch should be halted outright. 
 
 "We shouldn't be harvesting sardines any time the population is this low," said Geoff Shester, California program director for the conservation group Oceana, which contends that continuing to fish for them could speed their decline and arrest any recovery. 
 
 The Pacific sardine is the ocean's quintessential boom-bust fish. It is short-lived and prolific, and its numbers are wildly unpredictable, surging up and down in decades-long cycles in response to natural shifts in the ocean environment. When conditions are poor, sardine populations plunge. When seas are favorable, they flourish in massive schools. 
 
 It was one of those seemingly inexhaustible swells that propelled California's sardine fishery to a zenith in the 1940s. Aggressive pursuit of the species transformed Monterey into one of the world's top fishing ports. 
 
 And then it collapsed. 
 
 By mid-century sardines had practically vanished, and in the 1960s California established a moratorium on sardine fishing that lasted 18 years. The population rebounded in the 1980s and fishing resumed, but never at the level of its heyday. 
 
 Since the 1940s scientists have debated how much of the collapse was caused by ocean conditions and how much by overfishing. Now, researchers are posing the same question. 
 
 "It's a terribly difficult scientific problem," said Russ Vetter, director of the Fisheries Resources Division at NOAA's Southwest Fisheries Science Center. 
 
 Separate sardine populations off Japan, Peru and Chile fluctuate in the same 50- to 70-year climate cycle but have been more heavily exploited, Vetter said. West Coast sardines are considered one of the most cautiously fished stocks in the world, a practice that could explain why their latest rebound lasted as long as it did. The West Coast's last sardine decline began in 1999, but the population shot back up by the mid-2000s. 
 
 In recent years scientists have gained a deeper understanding of sardines' value as "forage fish," small but nutrition-packed species such as herring and market squid that form the core of the ocean food web, funneling energy upward by eating tiny plankton and being preyed on by big fish, seabirds, seals and whales. 
 
 Now, they say, there is evidence some ocean predators are starving without sardines. Scarcity of prey is the leading theory behind the 1,600 malnourished sea lion pups that washed up along beaches from Santa Barbara to San Diego in early 2013, said Sharon Melin, a wildlife biologist at the National Marine Fisheries Service. 
 
 Melin's research indicates that nursing sea lion mothers could not find fatty sardines, so they fed on less nutritious market squid, rockfish and hake and produced less milk for their young in 2012. The following year their pups showed up on the coast in overwhelming numbers, stranded and emaciated. ||||| Resources Thank the PFMC for Protecting the West Coast Ecosystem 
 
 The Pacific coast of North America supports one of the most vibrant and diverse marine ecosystems on Earth, largely because of the presence of thick schools of small prey fish such as Pacific sardines. Unfortunately, this crucial forage fish appears to be in the midst of a severe population decline. Its absence will be felt by dozens of species of West Coast seabirds, whales, sharks, dolphins, and commercially important fish such as salmon and tuna that depend on sardines as a major food source. In addition, because sardines have been a staple of commercial purse-seine fishing on the West Coast, their decline raises the potential for fishing pressure to shift to similar, but more abundant, schooling species of forage fish. 
 
 
 
 The Pacific Fishery Management Council, which manages fishing in federal waters off California, Oregon, and Washington, should do two things to help maintain a healthy Pacific Ocean: 
 
 Set conservative catch limits on sardines when the population is so low. 
 
 Fulfill its September 2013 commitment to prohibit unregulated fishing on forage fish species such as sand lance, saury, and lanternfish that are not currently managed or monitored. 
 
 
 
 Cause for concern 
 
 Populations of forage fish along the West Coast fluctuate widely, so a species can be abundant one year and dwindle unexpectedly the next. That’s because forage fish are highly dependent on the upwelling of cold nutrient- rich waters to stimulate the growth of phytoplankton, their primary food source. 
 
 The Pacific sardine fishery, immortalized in John Steinbeck’s novel Cannery Row, collapsed notoriously the 1950s. The November 2013 population estimate of 378,000 tons is the lowest in more than a decade, far below the peak of 1.5 million tons estimated in 2000 and a major decline by historical standards. Geological records of fish scales deposited off Southern California indicate that the unfished sardine population fluctuated naturally between a low of 400,000 tons to as much as 16 million tons. 
 
 
 
 Keeping an eye on the big picture 
 
 Forage fish account for more than one-third of the global catch of marine fish and are mostly used for industrial purposes such as feed for livestock, poultry, and farmed fish rather than being directly eaten by people. Most forage fish landed on the West Coast are exported for purposes such as bait in tuna longlining in Asia or as feed for farmed fish. In 2012, the Lenfest Forage Fish Task Force, a group of eminent scientists from around the world, calculated that forage fish worldwide are worth twice as much when left in the water—about $11.3 billion—as they are when caught because of their value as food for commercially important predators. 
 
 For further information, please visit: pewenvironment.org/pacificfish 
 
 
 
 Write the Pacific Fishery Management Council at: pfmc.comments@noaa.gov
– 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.