That Rattling Sound? It's The CA Coastal Food Chain Being Jerked By Warming
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Left high and dry in May was the Velella velella, crepe-paper-thin cousins of jellyfish equipped with sails that washed up by the millions on county beaches, pushed and pulled by wind and currents. They made a rare appearance last summer, too, and a gusty winter El Niño was also predicted — but fizzled out.
In June, beaches were red with piles of crimson tuna crabs drawn up from Baja to become fish food and selfie-fodder. Hot pink slugs called “nudibranchs” have been migrating from the south coast to populate the tide pools of Central and Northern California. Sea stars are still struggling with a wasting disease, which now seems to also be melting the spines off their prey; the urchins that have come out of hiding as sea stars disappear. Among the worst off is the sea lion. In Southern California, the “unusual mortality event” of 2013 is no longer unusual. Now it’s called the 2013-2015 Sea Lion Unusual Mortality Event. According to NOAA, last year’s sea-lion crash was likely due to food scarcity, “especially sardines.” And this year is worse.
The Pacific Fishery Management Council, which regulates the fishing industry here, closed the commercial sardine fishery due to an estimated 90 percent decline in the stock since 2007. It’s the first shutdown since the one in the 1950s (chronicled in Steinbeck’s Cannery Row). In both cases, overharvesting combined with natural boom-bust cycles created a worst-case scenario. But a mystery remains.
According to the fishery management council’s website, warmer temperatures favor sardines, yet “temperatures in the Southern California Bight have risen in the past two years, but we haven’t seen an increase in young sardines as expected.” Checkley, the Scripps professor, considers it a matter of timing. “The sardine population responds to long-term fluctuations in ocean conditions.” The recent warming is less important than a cyclical cooling phase (the “Pacific Decadal Oscillation”) that affected the North Pacific for the past 1-2 decades, says Checkley, who directs Scripps California Cooperative Oceanic Fisheries Investigations.
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http://www.sandiegoreader.com/news/2015/jul/11/ticker-rattling-sound-food-chain/#