The Humboldt Current

The Humboldt's productivity comes from a simple mechanism operating unusually well, and one additional feature that makes the fish unusually catchable.

THE MECHANISM IS EKMAN TRANSPORT. Persistent southerly winds blow along the coast; the rotation of the earth deflects the wind-driven surface flow offshore; and water rises from depth to replace it. Because the water below is cold and rich in nitrate, phosphate and silicate, bringing it into the sunlit layer produces an enormous bloom of phytoplankton.

THE GEOMETRY IS FAVOURABLE. The coast runs roughly north-south, the prevailing wind runs along it, and the shelf is narrow so the upwelled water reaches the surface close inshore. Those three conditions together are what make this system more productive than the other three great eastern boundary upwellings.

THE FOOD CHAIN IS SHORT, WHICH IS THE SECOND REASON FOR THE YIELD. Anchoveta feed directly on phytoplankton and large zooplankton, so there are very few steps between primary production and a harvestable fish. Each step in a food chain loses most of the energy, so a short chain converts far more of the bloom into fish.

THE OXYGEN MINIMUM ZONE IS THE THIRD FACTOR AND IT IS UNDERRATED. A layer of extremely low-oxygen water sits unusually shallow and unusually intense here, and fish will not live in it. That compresses the habitable water column into a thin surface layer, concentrating the anchoveta where a purse seine can reach them. The system is productive and its product is unusually accessible, which is a combination.

THE COAST IS DESERT BECAUSE OF THE SAME COLD WATER. Cold surface water suppresses convection and rainfall, which is why some of the driest land on earth sits beside some of the richest sea. It also means very little river input, so the nutrients come entirely from below.

AND THE SOUTHERN END TRANSITIONS INTO SOMETHING ELSE. Towards southern Chile the coast breaks into fjords, channels and islands with high rainfall and freshwater influence, and the upwelling logic no longer applies.

The species picture in this system is dominated by a single fish to a degree that has no parallel anywhere.

ANCHOVETA IS THE SYSTEM. The Peruvian anchovy has repeatedly supported the largest single-species fishery in the world by weight. Its biomass fluctuates enormously with ocean conditions, and in good years it is measured in many millions of tonnes. Almost all of it is reduced to fishmeal and fish oil for animal feed and aquaculture rather than eaten directly, which is one of the more consequential facts in global food systems.

SARDINE ALTERNATES WITH IT ON A LONGER CYCLE. Across the eastern Pacific and elsewhere, sardine and anchovy populations have historically alternated in dominance over multi-decadal periods tied to ocean regime shifts. The catalogue's Pacific sardine record belongs to this pattern.

JACK MACKEREL AND HORSE MACKEREL occupy the water offshore of the anchoveta and support their own large fishery, and the South Pacific jack mackerel stock has been a significant international management case.

HAKE IS THE DEMERSAL FISHERY, worked on the shelf and heavily fished.

CORVINA, JACKS AND SEA BASS OCCUPY THE INSHORE GROUND and are what the artisanal fishery and the shore angler actually catch. These are the fish that reach a plate as fish rather than as feed.

OFFSHORE AND TO THE NORTH IT TURNS TROPICAL. Where the cold system meets warmer equatorial water at the northern end, billfish, tuna and dorado appear, and the boundary between the two water masses is a fishing feature in the same way the Agulhas front is.

THE INVERTEBRATE FISHERY IS LARGE AND HIGH-VALUE. Chilean abalone, sea urchin, mussels, scallops, squid and giant squid are all substantial fisheries, and the benthic invertebrate sector is the one managed through territorial user rights.

AND THE PREDATOR ASSEMBLAGE IS THE VISIBLE CONSEQUENCE. Enormous seabird colonies, sea lions and cetaceans all depend on anchoveta, and their mass mortality during El Niño events is the most visible signal that the system has failed.

The disciplines here span an industrial fishery of global scale and a small-boat sector working the same water for quite different fish.

INDUSTRIAL PURSE SEINING IS THE DOMINANT PRACTICE BY VOLUME. Large seiners locate anchoveta shoals acoustically, encircle them and pump the catch aboard, delivering to reduction plants ashore. It is a highly capitalised, highly regulated fishery operating in short intense openings decided by survey results.

ARTISANAL SMALL-BOAT FISHING IS THE OTHER SECTOR AND IT FEEDS PEOPLE. Gillnets, lines, traps and pots worked from small boats within the inshore band reserved for them, targeting corvina, jacks, hake, octopus and shellfish for fresh consumption. This is the fishery a visitor sees at a harbour.

DIVING FOR BENTHIC INVERTEBRATES IS A MAJOR DISCIPLINE, particularly in Chile. Divers working from small boats harvest abalone-like gastropods, urchins and other high-value invertebrates from defined areas of seabed under territorial user rights. It is skilled, physically demanding and dangerous work, and decompression injury among these divers is a documented occupational health problem.

SHORE ANGLING WORKS THE ROCK AND SURF of a desert coastline, for corvina and jacks, in conditions where Pacific swell is the governing variable.

OFFSHORE SPORT FISHING CONCENTRATES AT THE NORTHERN END where the cold system meets tropical water, for billfish, tuna and dorado. This is a small fishery with a serious historical reputation.

KELP HARVESTING is a genuine coastal industry along the rocky shore, and it interacts with the invertebrate fisheries that depend on kelp habitat.

AND THE SEPARATION BETWEEN INDUSTRIAL AND ARTISANAL IS SPATIAL AND LEGALLY DEFINED, which is a comparatively rare degree of clarity in world fisheries and is the reason the two sectors coexist as directly as they do.

Seasonality here works on three timescales at once, and the longest one matters most.

THE ANNUAL CYCLE IS UPWELLING-DRIVEN. Southerly winds strengthen and weaken seasonally, and the upwelling with them, so production has an annual rhythm. But it is a modest signal compared with what sits on top of it.

THE FISHING SEASONS ARE ADMINISTRATIVE RATHER THAN NATURAL. The anchoveta fishery operates in openings — typically two main ones a year — whose start dates, lengths and quotas are decided from acoustic surveys rather than fixed in advance. Within an opening, the fishery can be closed at short notice if juveniles dominate the catch. The season is therefore a management output rather than a calendar fact, which is a genuinely unusual situation.

SPAWNING CLOSURES PROTECT THE MAIN SPAWNING PERIODS, and the timing is assessed rather than assumed.

EL NIÑO OVERRIDES EVERYTHING ON A TIMESCALE OF YEARS. When the warm phase arrives, the thermocline deepens, upwelled water is no longer nutrient-rich, production collapses, anchoveta biomass falls dramatically and the fishery may be closed entirely. Recovery follows the return of cool conditions. This is not a bad season; it is the system switching off.

LA NIÑA IS THE OPPOSITE PHASE and generally produces cold, strongly upwelled, highly productive conditions.

REGIME SHIFTS OPERATE ON DECADES. Longer-period changes in Pacific ocean state have historically flipped dominance between sardine and anchovy across the eastern Pacific, and a fishery built entirely on one of them is exposed to that.

AND THE PRACTICAL LESSON IS THE MANAGEMENT ONE. A stock that can change by an order of magnitude between years cannot be managed by a fixed annual quota set in advance, and the in-season survey-and-close approach used here is a direct response to that variability. It is one of the more instructive fisheries management stories anywhere.

Fisheries governance in this system contains two arrangements that are genuinely instructive and worth explaining rather than listing.

MANAGEMENT IS IN-SEASON AND SURVEY-DRIVEN. Rather than setting an annual catch limit in advance, the authorities run acoustic surveys, set a catch limit for a defined opening from the survey result, monitor the composition of the catch during it, and close the fishery at short notice if juveniles dominate. That is an adaptive system built for a stock whose abundance is genuinely unpredictable, and it is the structural response to El Niño.

INDIVIDUAL VESSEL QUOTAS REPLACED A RACE. Before quota allocation, the fishery was a competitive scramble within a season, which produced overcapacity, waste and unsafe operation. Allocating shares to vessels changed the incentive from speed to value, and the effects on capacity and safety are a documented case study.

TERRITORIAL USER RIGHTS FOR BENTHIC RESOURCES ARE THE OTHER NOTABLE SYSTEM. Defined areas of seabed are allocated to artisanal fishing organisations, which hold exclusive harvesting rights and management responsibility for their own area for shellfish and invertebrates. The theory is that a group with secure rights to a specific patch has reason to look after it, and the evidence from this coast is broadly supportive.

AN INSHORE BAND IS RESERVED FOR ARTISANAL FISHING in both countries, excluding industrial vessels, which is the spatial separation that lets the two sectors coexist.

SHARED AND STRADDLING STOCKS SIT WITH A REGIONAL ORGANISATION for the wider South Pacific, which was established in part because jack mackerel stocks straddle national and high-seas waters.

RECREATIONAL FISHING IS A SMALL CONSIDERATION IN THIS FRAMEWORK, generally subject to national rules on species and gear and, where it happens from a boat, to maritime requirements.

AND FISHINGHQ DOES NOT STATE WHAT ANY OF THIS CURRENTLY PERMITS. In a fishery whose openings are decided within a season, that would be a claim with a shelf life of days.

This system gave the world one of its most-used environmental terms, and its working vocabulary explains its management.

EL NIÑO IS A PERUVIAN FISHING WORD THAT BECAME A GLOBAL SCIENTIFIC TERM. Fishers on this coast named the periodic appearance of warm water around Christmas after the Christ child. The name was later attached to the whole Pacific-wide climate oscillation, which is now one of the most studied phenomena in earth science. Very few pieces of fishing vocabulary have travelled that far.

ANCHOVETA NAMES THE FISH AND, IN PRACTICE, THE FISHERY. When people on this coast talk about the fishery without qualification, this is what they mean.

VEDA MEANS CLOSURE and it covers both scheduled closed seasons and the short-notice in-season closures that are the characteristic instrument here. A reader following this fishery will meet the word constantly and should understand it as an active management decision rather than a fixed date.

OXYGEN MINIMUM ZONE IS A TECHNICAL TERM WORTH CARRYING because it explains why the fish are concentrated near the surface. Without it, the catchability of the anchoveta fishery is hard to account for.

TERRITORIAL USER RIGHTS IS A FISHERIES-POLICY TERM that this coast has made concrete. Reading about rights-based management anywhere in the world will bring a reader back to the benthic areas allocated along this shore.

AND REDUCTION IS THE INDUSTRIAL TERM THAT MATTERS ETHICALLY. It names the conversion of whole fish into meal and oil, and understanding that most of the world's largest fishery is a reduction fishery rather than a food fishery is the single most important thing to grasp about what this system's productivity is used for.

The history of this system is a sequence of booms built on the same production, and one of the most instructive collapses in fisheries science.

GUANO CAME FIRST. Seabird colonies fed by anchoveta deposited guano on the offshore islands over millennia, and in the nineteenth century it became an internationally traded fertiliser of enormous value. It was the first industry built on this system's productivity, and it was extracted faster than it accumulated.

THE ANCHOVETA FISHERY GREW EXPLOSIVELY IN THE MID-TWENTIETH CENTURY. Within two decades, Peru went from a minor fishing nation to the largest by tonnage in the world, on one species, mostly for fishmeal.

THE 1970s COLLAPSE IS A FOUNDATIONAL CASE IN FISHERIES SCIENCE. Heavy fishing coincided with a strong El Niño, and the stock collapsed dramatically. The fishery took many years to recover and the episode became one of the standard illustrations of what happens when a fishery is managed as though a variable stock were a stable one.

THE MANAGEMENT RESPONSE IS THE INTERESTING PART. Rather than concluding that the fishery was unmanageable, the response over subsequent decades built the in-season survey-and-close system, vessel quotas and juvenile-protection rules that now govern it. The fishery is still enormous, still volatile, and considerably better managed than it was.

CHILE'S BENTHIC FISHERIES WENT THROUGH A PARALLEL CYCLE. Serial depletion of high-value shellfish under open access led to the development of the territorial user rights system, which is now studied internationally.

EL NIÑO SCIENCE GREW OUT OF THIS COAST. What began as a local fishers' name for a warm current became, through the twentieth century, a central object of climate science, and its global teleconnections are now standard.

AND THE ETHICAL QUESTION HAS ARRIVED RECENTLY. Whether the world's largest fishery should be reducing edible fish to animal feed, on a coast where food security is not universal, is a live public argument rather than a settled matter.

The fishing culture of this coast has two quite separate halves, and only one of them is visible from the fishmeal statistics.

THE CALETA IS THE SOCIAL UNIT. Small fishing coves and landing places along the coast, with their boats, their sheds, their unions and their market stalls, are where the artisanal fishery lives. The organisations attached to them are also the bodies that hold benthic harvesting rights in Chile, so a caleta is an economic and a legal entity as well as a place.

THE FOOD CULTURE IS FISH-CENTRED AND SPECIFIC. Cebiche — raw fish cured in citrus — is a national dish on this coast, and it is built on exactly the inshore species the artisanal fishery lands. That gives fresh fish a cultural status quite separate from the industrial fishery's product, and it is one reason the artisanal sector's protected inshore band is politically durable.

THE TWO FISHERIES BARELY MEET. The industrial anchoveta fleet supplies a global feed industry; the artisanal fleet supplies a domestic food culture. They fish the same water and have almost no shared social world.

DIVING IS A DANGEROUS OCCUPATION HERE AND IS TREATED AS ONE. The invertebrate diving fishery has a documented record of decompression injury, and occupational safety in that sector is a real and continuing concern rather than a theoretical one.

RECREATIONAL ANGLING IS MODEST AND SHORE-BASED IN THE MAIN, with an offshore billfish fishery at the northern end that has a longer reputation than its current size suggests.

SEABIRDS AND SEA LIONS ARE PART OF THE DAILY EXPERIENCE of fishing here, in numbers that a visitor from a depleted coast finds startling, and their fluctuations are the most visible index of what the ocean is doing.

AND THE SEA IS TREATED WITH RESPECT FOR TWO REASONS: the swell, and the earthquakes. Leaving the shore immediately after a strong shake, without waiting for a warning, is ordinary coastal knowledge on this coast and is worth stating as such.

This coast breaks the single strongest correlation most people carry about the sea — that latitude predicts temperature — and it does so at exactly the latitudes where the assumption is most confident.

THE WATER IS COLD AND THE MAP SAYS IT SHOULD NOT BE. Upwelling drags deep water to the surface along this entire coast, so a sea at subtropical and tropical latitudes runs at temperatures a northern European would recognise. A visitor who has flown to a warm country and stands on a warm beach has no cue whatever that immersion will produce an involuntary gasp and loss of breathing control in the first seconds. That first minute is where cold-water drownings happen, and being a strong swimmer does not address it, because the failure is of breathing rather than of swimming.

THE SWELL HAS THE LONGEST FETCH ON EARTH BEHIND IT. Waves reaching this coast have crossed the open Pacific, so they arrive as long-period energy, in irregular sets, breaking heavily on exposed rock and steep beach. The clearest available evidence of the scale is operational rather than anecdotal: ports along parts of this coast close for SWELL rather than for wind. When a working port shuts because of waves on a calm day, that is the whole argument about ground swell made by people with money at stake.

WHICH MAKES THE SHORE MECHANISM THE FAMILIAR ONE. A platform that has been comfortable for an hour receives a wave substantially larger than everything preceding it, and the angler goes into cold, deep, moving water beside rock. Watch a mark for several full set cycles before committing. Choose a position with a way up. Wear flotation. Do not fish exposed rock alone.

THE SUN IS THE SECOND INVERSION. Low latitude, high altitude in places, clear desert air and a cool sea breeze produce severe ultraviolet exposure with none of the heat that normally prompts anybody to do something about it. Burning and dehydration develop quickly on a coast that does not feel hot, and dehydration degrades judgement before it produces symptoms a person notices.

AND THERE IS A HAZARD HERE THAT APPEARS NOWHERE ELSE IN THIS CATALOGUE AS SAFETY ADVICE. This is a seismically active coast, and a strong earthquake near it can generate a tsunami with very little travel time. The local rule — and it is genuine local safety knowledge rather than folklore — is that a strong shake felt at the coast is itself the warning: move inland and uphill immediately, and do not wait for an official alert, because on a near-field event the alert may arrive after the wave. Anybody fishing this coast should know where the high ground behind them is, in the same way they would know where the exit from a platform is.

AND THE COAST IS ARID, EXPOSED AND IN PLACES REMOTE, with long distances between towns and limited rescue capacity. Check current marine forecasts and local warnings, tell somebody the plan, and treat the cold water as a fact rather than a surprise.