>On that day the swell and wind were formidable, but we were determined to get offshore. We hoped to get a good look at the hammerhead sharks — typically a subtropical species — that had been spotted at the surface by one or two multiday dive boats over the past few weeks. We couldn't believe our luck when one showed up and interacted closely (at times, very closely) with us for three hours.
>Among divers the rumored cause for the oddities of the summer of 2014 was El Niño (the warm phase of the El Niño Southern Oscillation), an ocean-atmosphere interaction in the east-central equatorial Pacific that strongly influences ocean conditions and weather patterns. However, the U.S. National Oceanic and Atmospheric Administration (NOAA) had not confirmed the presence of El Niño conditions. Meanwhile, Washington state climatologist Nick Bond had already come up with an alternate name for the odd patch of warmer-than-usual ocean off the coast of the Pacific Northwest: "The Blob." This phenomenon, thought to be the result of locally persistent high pressure that inhibited normal wind-driven oceanic upwelling and cooling, had spread along the West Coast and encompassed multiple stretches of ocean from Alaska to Mexico.
>By the time NOAA confirmed the arrival of El Niño conditions in March 2015, it was hard to believe that things could get any stranger, but they did. Sea bird and California sea lion populations began experiencing devastating die-offs. In April 2015, strong west-to-east surface winds blew masses of violet-blue Velella velella, open-ocean hydrozoans related to jellyfish, onto beaches in California, Oregon and Washington. And in June 2015 I watched in amazement as pelagic red tuna crabs (a squat lobster-like crustacean normally found near central Baja California) swarmed one of our few remaining local kelp beds and ultimately littered the coastline from San Diego to Los Angeles.
>The peculiarities didn't stop there. In July and August 2015, smooth hammerhead sharks were bumping near-shore kayak fishermen so commonly and assertively that local beaches were closed on multiple occasions. On the docks, anglers posed proudly next to bluefin tuna, caught only 10 miles offshore, and local photographs of finescale triggerfish and Guadalupe cardinalfish became commonplace. In September 2015, I hovered in disbelief next to the barren propeller of the HMCS Yukon, a San Diego-area artificial reef that had been thickly encrusted with giant plumose anemones only 12 months prior. And only a month after that, a cluster of wahoo passed me at a Catalina Island dive site days before I photographed a pulsing Australian spotted jellyfish near the San Diego harbor. The world — at least, the underwater world I frequented on a regular basis — seemed to have gone stark raving mad.
>Parnell's key concern is further overgrowth of invasive Sargassum horneri. "Two years ago, we were seeing isolated pockets of it, but now it's popping up everywhere," he said. "If we lose the kelp in an area completely, sargassum can easily take over because it will no longer be suppressed by giant kelp shading."
>Parnell, however, says this may be one of the biggest reasons to remain optimistic. "Strong storms can revamp the bottom structure, remove urchin barrens and clear out the understory kelps, providing renewed areas for giant kelp to grow," he said. "El Niño may bring a series of storms, but we need to remember that those large storms act as a reset button for kelp forests in Southern California."
>© Alert Diver — Q1 Winter 2016