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With a final folding of her cape this month, La Nina settles back into the equatorial Pacific depths and returns that cherished measure known to oceanographers as the “neutral ENSO,” or (sigh) “normal year” (http://www.cpc.ncep.noaa.gov/products/analysis_monitoring/enso_advisory/ensodisc.html).

On the central California coast at Santa Cruz, La Nina’s effect was a benign drought, or just a sunny winter. We enjoyed the beaches in January. The water has been cold, that’s all. Recently Tod, a local guy, recounted how he took his son out on such a blissful winter day off Cowell’s beach in his kayak and pulled up two 16-inch sand dabs in only eight feet of water. Sand dabs are generally “nice-sized” at 8-10 inches. I suspect these “giants” were spawning females.

Fishing is a great way to discover ongoing mysteries out in the water. Half the time it’s just as amazing at what you don’t catch as what you do. Of note for this season, has been the fine sand dab and Dungeness crab presence.

Climate-and-reservoir-wise, we need more rain, but that’s about it. The rest of the country cannot say the same. A cold wet sop north of us and a hot drought south of us stretch eastward.

More broadly, this tango of La Nina with her brother, El Nino, on winds issuing east to west across the Pacific has informed the modern world in the last few decades of the global significance of Pacific ocean wind, current, and temperature cycles. First to notice this were fishermen in the 1600s (http://www.esrl.noaa.gov/psd/enso/).

When for centuries the strange disappearance of anchovy schools off the coast of Peru every several years at Christmas time–with uncharacteristic warm water, lost wind, and heavy rains–remained a mystery, today it’s common knowledge that El Nino and La Nina cast spells on the weather, and maybe even your fate, from far away to your very lap.

Within brag-able memory (mine at least), this reality was especially felt here in Santa Cruz with the El Nino winter of 1997-8. Endless tropical storming punched out 60 Wharf pilings like molars in a brawl, and swaths of strangely warm water ushered big game fish like bluefin tuna, marlin, and barracuda to Monterey Bay.

How We Got to Here
The crucial connections in the story of the Pacific’s enormous weather cycles formed in the minds in just a few people over decades. In the 1920s Sir Gilbert Walker first matched seemingly dissimilar atmospheric pressures while trying to predict monsoons (or their failure) in India after a terrible famine in 1889. He noticed contradictory barometer recordings at Darwin in Australia vs. Tahiti in the Pacific. Every few years a rise at Darwin saw a fall at Tahiti, and vice versa. He gave it a name: the Southern Oscillation. He grew convinced droughts in Africa, South America, and mild winters in his native Canada were all somehow related to this hinge. Nobody believed him (http://www.earthgauge.net/wp-content/fact_sheets/CF_ENSO.pdf).

Decades later in the late 1960s, Jacob Bjerknes, a meteorologist, realized that far flung weather events (if not calamities) locally recorded in South America, Australia, and Asia were not separate but part of a dynamic between the sea and the atmosphere Pacific-wide. He coined it ENSO (El Nino Southern Oscillation). Since the mid 1970s scientists started looking and matching history to this pattern. This five-ten year dance cycle has proven linked to enormous weather spin offs in far away places, and has brushed fateful strokes through human history.

Crop failures in France from El Nino-linked winters in the 1780s had a hand inciting the French Revolution. The El Nino of 1998 is blamed for harsh drought in Africa, while dumping 10 times normal rainfall in Ecuador and Peru, with resulting floods. The 1972-3 El Nino has been tied to crushing droughts and crop failures as far away as the (then) Soviet Union, India, and the Sahel region of Africa. Generally, El Nino suppresses hurricane development in the central Atlantic while La Nina does the opposite, as our eastern seaboard has learned.

In Santa Cruz, La Nina’s effect as she leaves us has been cold water temperatures, and this reaches up coast to Canada. Here, the fishing surprise of the season has been the good Dungeness crab and sand dab catching.

Enter Decadal
The concept of ENSO is actually easy to grasp for our modern byte-sized attention spans. A cycle of 3-7 years fits nicely into research budgets and news bites. One can imagine a sea-saw along the equator with low pressure on one side and high pressure on the other that starts a wind rolling. Winds along the sea-saw pile water up at the destination end most years, which roll back when the winds stop in other years. Got it. Winds pushing water ahead while drawing up deeper water in replacement makes intuitive sense. Water interacting with air over it as it travels along is a Canterbury tale. But that is not the whole story this year.

In this spring into summer seasoning, we are facing a much grander ocean cycle. This cycle spans the entire north Pacific from the equator to Alaska, from Russia to Washington state. And it unfolds over a much longer newsbyte: 20-30, even 50 years. Like El Nino/La Nina, this cycle too was first realized by one person, Steven Hare, who in 1996 looked at the numbers with a few colleagues and saw a pattern. He was looking for a pattern to fit one mystery—the swings of salmon catches in the north Pacific.

He found that good salmon years alternated with cold water on opposite sides of the Pacific from Oregon-Washington-Canada to Japan-Siberia. Like the ENSO sea-saw, when one side was up, the other was down. He called it decadal oscillation, or Pacific Decadal Oscillation (PDO). Unlike the sea-saw plank model of ENSO at the equator, PDO is shaped like a horseshoe with the rungs planted in Siberia and the top hoop almost, but not quite, reaching to the continental US (http://jisao.washington.edu/pdo/).

Also unlike ENSO, which is caused by winds stopping or re-blowing harder along one alley, the Pacific Decadal Oscillation results from several cycles spun from different sources pooled together. ENSO can affect the wider pattern, and PDO can affect the narrower pattern. Both repeat, but not exactly every time, or any time.

PDO displays a “positive” “warm” phase and a “negative” “cool” phase, with each playing out across the north Pacific. Hare seems to have pegged the prime reference to the US west coast. A negative (cold) phase is negative in Seattle and opposite in Tokyo; a positive (warm) phase is positive in Seattle and opposite in Tokyo. The bulk of the temperature mass inside the horseshoe for either phase is on the Japan/Russia side.

During the positive phase, the western Pacific is cool and the eastern (US) warm. During the negative phase, the opposite occurs. As it turns out, the El Nino/La Nina tango of 2008-11 occurred within a surrounding mantle of negative-phase decadal oscillation. The El Nino warming front popped up within a larger cold pool. The retreating La Nina reversal just slips “cool” back into “cold.” All this blowing and swirling, warming and cooling of vast ocean areas intimately affects biology in the ocean.

Most recently and locally, another researcher, Francisco Chavez from Monterey Bay Aquarium Research Institute (MBARI), matches the PDO cycle with the sardine and anchovy cycles in Monterey Bay and even Pacific-wide. He notes that sardines are plentiful in the warm phase, while anchovies are plentiful in the cold phase.

In the 1930s the fabled sardine fishery boomed in a warm phase and died out by the 1950s as the ocean shifted to a cold phase. In the cold phase anchovy populations boomed. Sardines appeared big time again during the 1970s and phased out in the mid 1990s as the waters cooled. Anchovies started filling the vacancy and flourishing. Chavez has found this has occurred in lock step all over the Pacific over the last 100 years (http://www.mbari.org/news/news_releases/2003/nr01-chavez.html).

So what fish schools do we have now? If my bait jigs are any measure, we have both. Over the last few years I have found sardine schools swimming next to anchovy schools. Both swim under the Wharf.

The Spell of Salmon
You might quiz a lot of people to find one who isn’t hypnotized by a film-clip of salmon leaping upstream. Even those who don’t crave the steaks or the omega-3 oil love the story of the migration upstream and beauty of the creature. The mighty salmon cuts across all political or philosophical camps. We modern humans are wound in a Sisyphusian bargain trashing habitat, while promoting hatcheries to restore dwindling populations. That’s a long slippery slope to push the boulder atop.

Determined efforts at hatchery production can be a thankless nearly hopeless task. Beyond the endless toil and quality control planning, the budgets and volunteering and hoping, hatchery successes can be quashed by ocean conditions. There are good years and not so good years. The wish of every hatchery hand is to help river-incubated smolts to a welcoming ocean where their numbers will grow to self sustaining returns and populations. This year seems to be just such a wish come true.

Salmon love cold water but more is happening than La Nina relinquishing her cold water to PDO cold water. Upwelling, presence of plankton and copepods, and krill, and salinity all have hands. The NOAA Fisheries Science Center reports as of January if cold conditions persist into spring (we’re there) this will be the “best observed in recent years” (http://www.nwfsc.noaa.gov/research/divisions/fed/oeip/g-forecast.cfm). But that is for juvenile fish just entering the ocean. What about the fat fish already making a living out there for this year?!
The California Department of Fish and Game recently held a public meeting to release their ocean abundance forecast in Santa Rosa. For once, it’s all good news, even colossal if you expect to fish the north coast (http://www.times-standard.com/fishingthenorthcoast/ci_20079602). Based on jack salmon returning to river stations in 2011 and using a multiplier to derive an estimate of the numbers that did not enter the river and are still out there, the world is rosy. They estimate a population of 1.6 million Klamath River salmon alone. The same sampling equations yield 819,400 Sacramento River salmon out there happily chasing down sardines and anchovies and squid.

For us the issue will be how many of those will find their way into Monterey Bay. If the recent stories of humpback whales lingering less than a mile out of Santa Cruz Harbor through October because they like the anchovies is any clue, look for a lot smiles. I can’t think the last whale ate the last anchovy.

So what about the poor salmon out there itching to go back upstream? What if you catch it before . . .? I have thought long and hard about that one. The dilemma is the same for hunters. How can you kill what you love? And then eat it? Ewww! That is a good question for moral living. How can you? The answer to that one is there are no easy answers. One might ask the fish in the sea to stop biting each other.

So light a candle and pop a beer for inertia. Pray for cold water into summer!

Personally, I’m dedicated to making the next great ocean discovery. One genius calls for another. There’s a whole quantum dynamic out there unserving dumb luck and bait recognition. I might call it the wishbone effect, but I don’t know.

I simply need more data!

Last updated: 3/16/2012 8:04:26 AM