National Geographic : 2016 Sep
68 national geographic • september 2016 Hawaii; tiny crustaceans with cobalt egg sacs. He cataloged nearly 20 new species that be- longed far away. Compared with krill, these zooplankton were limp-lettuce side salads: smaller and less nutritious. As this low-cal diet coursed through the food web, larval walleye pollock, common in the Gulf of Alaska, reached their lowest numbers in three decades. Halibut caught in Cook Inlet had mushy flesh—a syndrome associated with poor nutrition. Coho salmon returned to West Coast streams as malnour- ished runts. These changes coincided with other shifts. Sardines, already in decline, de- creased so much that an industry made famous by John Steinbeck’s novel Cannery Row shut down for the first time since rebounding from its collapse in the 1950s. Sardine and anchovy populations are cyclical; their precipitous drop likely had little to do with warm water. But the impact was more pronounced because the un- usual heat redistributed the remaining fish. shrimps, they are gobbled by auklets, cohos, basking sharks, and whales. Anchovies and sardines eat them and then get wolfed by big- ger fish and sea lions. At this time of year, krill should be abundant, but Peterson’s haul re- veals mostly soupy algae and small jellyfish, which provide little sustenance. His team hasn’t seen krill in months. “It’s been like this nonstop,” he says. Higher ocean temperatures have thrown this system out of whack. Not long after the warmth arrived, shelled octopuses more com- mon in the South Pacific appeared off Southern California. Tropical sunfish and blue sharks were caught in the North Pacific. Market squid, common off California, laid eggs in southeast Alaska. A few venomous yellow-bellied sea snakes from Central America slithered across beaches near Los Angeles. Peterson’s team caught tropical or subtropical zooplankton he’d never seen: rainbow-hued, beetle-shaped copepods; minuscule iridescent creatures from A mola, or ocean sunfish, chases a by-the-wind sailor. With temperatures in some places reaching seven degrees Fahrenheit above average, many subtropical marine animals, such as this sunfish, came close to Pacific shores.