Year in Review: Ocean changes upend North Coast fisheries
BODEGA BAY - In any other year, the large bins of Dungeness crab that are loaded dockside in this busy fishing village and rolled out by truck to be sold and served during the holidays would seem like no big deal.
But after an unprecedented delay in the 2015-16 commercial season forced local crabbers to leave their boats tied up through winter and on into spring, the tons of meaty crustaceans that landed in port this month have been a welcome sign of normalcy restored, if only for a moment.
For here on the edge of the Pacific, where commercial fishing remains a way of life, once reliable ocean rhythms have been seriously unsettled of late, confounding those who depend on predictable, seasonal cycles and highlighting future uncertainties.
Even the current Dungeness season lurched off to a bumpy start, with the fishery opening piecemeal and mostly behind schedule, a symptom of widespread marine anomalies that have prevailed for the past three years, threatening everything from seabirds and sea lions to treasured catches such as salmon and abalone.
“The ocean is changing,” one glum crabber aboard the vessel New Horizon said while waiting to unload his catch recently at Tides Wharf. Offshore a strong storm was building and the fisherman summed up the fishing industry’s environmental troubles with hard-earned experience.
Irregularity “is starting to look like the new normal,” he said.
Scientists and fishermen alike are unsure about the degree to which recent upheaval fits within the ocean’s normal rhythms - which are complex - or whether it is part of some longer-term trend, perhaps linked to global climate change and its many ripple effects.
It’s likely a bit of both, given the context of the Earth’s warming, though more immediate atmospheric conditions have been the primary suspect, scientists say.
“Climate change syndrome is definitely having an impact,” said John Largier, professor of coastal oceanography at the UC Davis Bodega Marine Laboratory. “What is very difficult to tell is how much.”
It appears that an expanse of high-temperature water along the coast of North American known as “the Warm Blob” is mostly to blame for recent disturbances affecting the coast of California, causing significant redistribution of wildlife, disruptions in the food web and large-scale mortality in a variety of animals.
First observed in the Gulf of Alaska in 2013, the blob was linked to a high pressure ridge parked over the north Pacific in 2011 that diverted winter storms, contributing to California’s drought and weakening winds that normally would help absorb heat from the ocean and stir up the cold water that makes the North Coast immensely productive breeding and feeding grounds for marine wildlife.
The blob was reinforced by warm El Niño waters driven north from the equatorial Pacific last year, contributing to what some scientists now think of as a “multi-year ocean heat wave,” with temperatures around 7 Fahrenheit above normal in some locations, but up to 10 degrees above normal in the most extreme examples, said Nate Mantua, a research scientist at the National Oceanic and Atmospheric Administration’s Southwest Fisheries Science Center in Santa Cruz.
“One of the things that is clear is there’s a lot of variation from year to year along the Pacific Coast, and some of that is tied into natural patterns, like El Niño,” Mantua said. “But what we saw in 2014, ’15 and the first part of ’16 was warmer than anything we’ve seen in our historical records, going back about 100 years.”
Notable impacts for the North Coast included last year’s persistent, widespread “red tide” - a bloom of Pseudo-nitzschia, a single-celled organism that thrives in warm water and produces a neurotoxin called domoic acid. In addition to contributing to fatalities among sea lions and other pinnipeds, the toxin shut down last year’s Dungeness crab fishery for 4½ months, including the lucrative holiday season, pushing many in the North Coast’s commercial fleet to the brink of insolvency.
The crisis isn’t over. Lingering toxicity along the California coast continued into early fall this year, though in a more localized distribution pattern, UC Santa Cruz professor of ocean health Raphael Kudela said during an October public hearing on fisheries and aquaculture.
Warmer-than-usual water also is believed to have contributed to the collapse of the bull kelp forest off Sonoma and Mendocino counties, along with an explosion of purple urchins that have devoured remaining plant life.
The urchins, in turn, are out-competing red abalone, the shellfish that attract thousands of sport divers and pickers each year to the Sonoma and Mendocino coast.