Seven years ago I was in New Zealand, sitting out a refresher course — the survival drills and firefighting that every ship's officer repeats whether or not he has spent the last decade at sea — when I fell into conversation with an older man near the back of the room. I am a career yacht captain; more than thirty years at sea have carried me across most of the world's oceans, often to the remote, little-travelled corners of them. He was a fisherman — an Australian who had spent the better part of thirty years running purse-seiners for one of the big Spanish companies operating out of the Seychelles. We did the usual sailor's accounting of weather and ports, and then we arrived, as seafarers always do whatever their trade, at the subject of what the ocean used to be.
I told him what I had seen in my earlier years at sea, from the late 1980s into the mid-1990s: tuna and dolphin moving in schools so vast they changed the colour of the water clear to the horizon, an abundance I took, at the time, to be simply the way the sea was. And then, somewhere in the mid-1990s, the sharp falling-off — the schools thinning, breaking apart, and finally not being there at all.
He nodded the whole way through, because he had watched precisely the same thing happen in the Indian Ocean, from the deck of a vessel whose entire purpose was to catch them. The great schools he had chased as a young man were gone. Not merely smaller — gone, in the form we had both known them. We had known different oceans, a hemisphere apart — he hauling fish from one, I crossing many under sail and command — and we were describing, almost word for word, the same disappearance.
What stayed with me was who he was. Not a campaigner, not a scientist with a thesis to defend, but a man whose living depended on the fish being there — an insider of the very industry that had done the catching — telling me, without any apparent agenda, that the ocean he had started his career in no longer existed.
I · The trouble with remembering
Two men remembering is not a dataset, and I want to be honest about that from the outset, because the gap between what sailors remember and what science can prove is the real subject of this essay.
There is a name for the trap. In 1995 the fisheries scientist Daniel Pauly described what he called "shifting baseline syndrome": the tendency of each generation to take the depleted ocean it inherits as the natural one. The young fisherman accepts his thin catch as normal; the old-timer, looking at the same water, sees the scraps of something that was once overwhelming. Because each generation resets the baseline a little lower, the long decline is quietly erased — not through any conspiracy, but through the simple failure of memory to outlive the people who hold it. Pauly's point was uncomfortable for his own profession: fisheries are often managed against a reference point that is already a ruin, so "recovery" can mean restoring a sea that was itself a shadow.
That is exactly why a fisherman and a ship's captain comparing notes is not nostalgia. Memory is not measurement — but in the absence of anyone counting the ocean before the industrial fleets arrived, the recollections of the people who were there are sometimes the only record of the older, fuller sea. The danger is not that we misremember the abundance. The danger is that no one will remember it at all, and the emptied ocean will become the one we defend as normal.
The danger is not that we misremember the abundance — it is that no one will remember it at all.
II · Ten fish in a hundred hooks
The science cannot confirm the absolute — that the great schools exist nowhere now — and an honest account should not pretend it can. What the science does confirm is a collapse steep enough to make the captain's memory entirely credible.
The landmark estimate came in 2003, when the marine biologists Ransom Myers and Boris Worm published an analysis in Nature drawing on half a century of catch records. They found that industrialised fishing typically stripped about eighty percent of a fish community's biomass within fifteen years of moving into new grounds, and estimated that large predatory fish — the tuna, swordfish, marlin and sharks — stood at roughly ten percent of their pre-industrial levels. Myers put it without hedging: there was, he said, no blue frontier left. Tellingly for anyone who has watched a fishery age, they noted that early longlines once brought up something like ten large fish for every hundred hooks, and that the steepest crashes happened in the first years after a fleet reached fresh water — usually before anyone realised what was being lost.
That ninety-percent figure became famous, and it deserves an asterisk. A number of tuna scientists challenged it hard: in a 2005 exchange in Nature, and in later work, researchers including John Hampton, John Sibert and Tom Polacheck argued that Myers and Worm had leaned too heavily on catch-per-hook as a stand-in for abundance, and that for some pelagic stocks the picture was overstated. The dispute was real and it was technical, and it was never fully resolved. But the direction was never seriously in doubt. Later assessments built on proper stock data found declines that were less apocalyptic and still profound. The argument was about the size of the catastrophe, not its existence.
For one ocean, though, we no longer have to rely on a contested global average. We can simply read the Indian Ocean's own ledger.
III · The belt that is being emptied
The Indian Ocean Tuna Commission — the intergovernmental body charged with managing these stocks — declared Indian Ocean yellowfin tuna overfished in 2015. For most of the decade since, its rebuilding measures were blunted by objections and missed targets, even as its scientists put the spawning biomass below half its unfished level. In 2024 a fresh assessment controversially reclassified the stock as no longer overfished — a reversal that observer groups and members of the European Parliament have openly disputed. Yet when the commission finally agreed its first binding catch limit and country-by-country quotas, in May 2026, it set the annual ceiling above the maximum its own scientists judge sustainable; and the conservation group Planet Tracker has warned the population could still begin to collapse this decade. WWF's Indian Ocean tuna specialist reduced it to a single line that any sailor would understand: when it comes to yellowfin, he said, we are eating our capital.
The commission's failure is not mysterious. The European purse-seine fleet has historically taken the largest share of Indian Ocean yellowfin and is the biggest deployer of drifting fish-aggregating devices — floating rafts, often satellite-buoyed, that draw tuna together to be scooped up wholesale, and that catch juvenile fish in their millions before they have ever spawned. When the commission has tried to limit those devices, European objections have helped gut the measures: under the rules, a member that objects need not comply. And the official catch is itself an undercount — catch reconstructions suggest the Indian Ocean's industrial fisheries for large pelagic species have under-reported their take by something approaching a quarter to a third for decades. The number on the page is the floor, not the ceiling.
This is the water the West African and European fleets call the "yellowfin tuna belt." It is being emptied with the meticulousness of an industry that knows exactly what it is doing, and a regulator that cannot, or will not, stop it.
IV · Further and further south
The detail that has stayed with me longest from that conversation in New Zealand was the captain's account of the chase moving south. Year on year, he said, the fleets had to push further into the southern Indian Ocean to find the schools — out of the warm equatorial water where the abundance had once been reliable, toward the cooler latitudes. It is the kind of observation that sounds like a single cause and turns out, on inspection, to be three braided together.
The first is the ocean itself moving. As surface waters warm, marine species tend to shift toward the poles and into deeper, cooler layers, and tuna — whose distribution is tightly governed by temperature — are a textbook case. A 2017 study of catch records from 1965 to 2011 found that the proportion of tropical tuna in subtropical catches rose over time even as tropical-zone catches of those same species fell in the Atlantic and Indian Oceans — consistent with populations drifting poleward. Models for the Indian Ocean specifically project the suitable habitat of albacore shifting southward through this century, and that of skipjack moving south and east, with the equatorial western Indian Ocean — the Somali and Mozambique waters — becoming less hospitable to surface schools after around mid-century. The schools the captain remembered may, in part, simply have left.
The second cause is plainer: a fished-out ground forces a fleet to range further for the same haul. This is the northern-Sri-Lankan fisherman's complaint rendered at industrial scale — the same fish, found only by steaming longer and burning more fuel. And the third cause is a caution against blaming everything on the climate. When researchers examined the southward drift of tropical-tuna fishing effort in the Atlantic, they found it could be explained substantially by technology and the shifting geometry of access agreements — bigger vessels, longer trips, FADs, and the political map of who is allowed to fish where — with temperature a contributing factor rather than the whole story. The fleet moves south for reasons of physics, of depletion, and of paperwork, all at once.
A fair essay has to add one more complication: the species do not all answer the same way. Some models expect bigeye and the temperate tunas to retreat poleward while skipjack and yellowfin persist, even concentrate, in certain tropical zones. The ocean is not emptying uniformly; it is being redistributed, and a redistribution that the fish can perform and the coastal fishing village cannot is its own kind of injustice.
V · Who empties the belt
If the first essay in this pair has a sequel, it is here, because the Indian Ocean is being worked by the same playbook — only the gear and the flags have changed.
Consider the Seychelles fleet. On paper, the islands field a purse-seine fleet to rival Spain's. In practice, investigators have shown that the Seychelles-flagged vessels are effectively in European hands — owned by Basque Spanish companies such as Pevasa, Albacora and Echebastar, and the French firm SAPMER — frequently held through nominal shell owners registered in tax havens like Belize, a structure whose only purpose is to obscure who truly profits. The catch, on the order of two hundred and ninety thousand tonnes a year, lands through just three ports: Victoria in the Seychelles, Port Louis in Mauritius, and Diego Suarez in Madagascar. Access runs through European fisheries agreements with the coastal states, paid for in fees that loom large in small national budgets and buy a quiet acquiescence.
And the manoeuvres are the ones we have already met. As the commission has, belatedly, begun forcing modest catch cuts — the EU agreed to trim its own yellowfin take by around a fifth — a Blue Marine Foundation investigation reported in 2026 that European firms have begun reflagging purse-seiners to Mauritius, Tanzania and Oman, tapping those nations' quotas and the concessions granted to smaller states to keep their own catch up. The same fleet, Blue Marine found, has a habit of going dark: more than three-quarters of the EU-owned vessels studied switched off their satellite transponders for stretches longer than a month, one for over a hundred days at a stretch, often in exactly the waters where the richest catches were reported. The head of those investigations described the trend in three words that could serve as an epitaph for the whole region: the Indian Ocean, she said, is becoming increasingly opaque.
Reflagging to small island states. Beneficial ownership hidden in tax-haven shells. Transponders switched off over the best fishing. A regional commission whose decisions any member can veto by simply objecting. It is the high-seas playbook of the first essay, transplanted into national waters and dressed in development agreements — the same architecture of plausible deniability, built this time around a body that was supposed to be the solution.
VI · The voices on the shore
The captain saw it from the bridge of a purse-seiner. The clearest accounts, though, come from the people left holding the empty nets when the industrial fleet has moved on.
In the Kenyan border village of Vanga, a sixty-five-year-old handline fisherman named Chapoka Miongo, three decades on the water, summed up the new scarcity in four words: tuna is not for everyone. A fellow Vanga fisherman described the impossibility of the contest directly — the small wooden boats simply cannot compete with the large European and Asian vessels that use satellite technology to track the tuna shoals across the whole ocean. The structural squeeze can be counted: in Tanzania, dwindling inshore stocks have already pushed an estimated three-quarters of fishers to venture further offshore, into water their boats were never built for, while Kenya's marine fish biomass is projected to fall by as much as forty percent by 2050. WWF has estimated that five Western Indian Ocean nations — Kenya, Tanzania, Mozambique, South Africa and Madagascar — were losing as much as a hundred and forty million dollars a year to illegal fishing alone in the years to 2021.
This is the part the catch statistics never quite capture. The tuna that leaves the belt does not leave evenly. The industrial fleet, flexible and far-ranging, follows the fish south or simply buys access to the next country's water. The handline fisherman in Vanga cannot follow. He is left on a shrinking patch of a depleting sea, watching boats he will never board chase fish he can no longer reach — and absorbing, in his own lifetime, the full violence of a baseline shifting downward.
VII · What the witnesses keep
I have thought often about that conversation in New Zealand, and about how easily it could have been mistaken for two sailors exaggerating the past. That is the precise reflex shifting-baseline syndrome predicts: discount the witnesses, accept the diminished present, and let the memory of abundance die with the people who carry it.
But the witnesses, in this case, were right, and the ocean's own ledger has caught up with them. The Indian Ocean's signature tuna was officially overfished for a decade, its rebuilding plans blunted by objection; its spawning stock fell below half its former weight; the limit finally agreed for it was set above the science; the fleets that empty it hide behind flags of convenience, shell companies and darkened transponders, and the body meant to govern them can be neutered by a single objection. The captain who told me the great schools were gone was not romanticising. He was reporting — as accurately as any instrument — the difference between the sea he began his life in and the one he would end it in.
The first of these essays asked why, knowing what we know, we still permit the industrial plunder of the commons. This one asks something quieter and, in the long run, more dangerous to ignore: whether we will even remember that there was more. Because the schools that stretched to the horizon were real. They were the baseline. And a generation that never saw them will, unless someone keeps insisting otherwise, grow up believing the thin and guarded sea we have made is simply the way the ocean has always been.
It is not. Hold that in mind, the way the old man at the back of the room held it — quietly, stubbornly, against the forgetting.
Sources
Shifting baselines (I): Daniel Pauly, "Anecdotes and the shifting baseline syndrome of fisheries" (Trends in Ecology & Evolution, 1995); the Oceana / George Monbiot interview on shifting baselines.
Predator decline and the ninety-percent debate (II): Ransom Myers and Boris Worm, "Rapid worldwide depletion of predatory fish communities" (Nature, 2003), with the rebuttals by Hampton, Sibert et al. (Nature, 2005) and Polacheck (Marine Policy, 2006).
Indian Ocean yellowfin (III): Indian Ocean Tuna Commission Scientific Committee assessments, with reporting by Mongabay, SeafoodSource and WWF on the overfishing declaration, the halving of spawning biomass and the catch-cut advice; the Frontiers in Marine Science (2023) catch-reconstruction study on under-reporting.
The chase moving south (IV): Monllor-Hurtado et al. (PLOS ONE, 2017) on poleward shifts; Mondal et al. (2023) and Dueri et al. on Indian Ocean habitat projections; Rubio et al. (Fish and Fisheries, 2020) on technological and management drivers.
The Seychelles fleet, reflagging and going dark (V): Mongabay and the Blue Marine Foundation on European beneficial ownership, FADs, reflagging and AIS "going dark," with Associated Press (2026) coverage; the IDDRI Indian Ocean tuna report on fleet structure.
The voices on the shore (VI): The Christian Science Monitor (2022) for the Vanga, Kenya testimony; Standard Media (2026) on Tanzanian displacement and Kenyan biomass projections; WWF estimates of Western Indian Ocean losses to illegal fishing.
On testimony: Personal testimony from the author and from an unnamed Australian purse-seine master is presented as eyewitness recollection, corroborated by — not substituted for — the published record. Academic papers are cited by title and journal for lookup; institutional and news sources are linked.
Further Reading
This essay argues a position. Readers who want to test it against the other framings — the body that manages the fishery, the coastal states pressing for a fairer share, the distant-water fleet it indicts, the certifiers, and the independent investigators — will find the following starting points useful. Reasonable people in this field disagree, sometimes sharply.
The body that governs the fishery: the Indian Ocean Tuna Commission — its stock assessments, conservation resolutions, and the catch limits adopted at the May 2026 session, read directly.
The coastal states' own case: the G16 group of like-minded Indian Ocean coastal states, on why the distant-water nations should carry the conservation burden.
The distant-water fleet's framing: the Europêche Tuna Group, the EU purse-seine sector's own account of the same meetings and measures.
The EU's official position: the European Commission, DG Maritime Affairs and Fisheries, on its Sustainable Fisheries Partnership Agreements and catch-cut record.
The industry-engaged sustainability view: the International Seafood Sustainability Foundation, a body of processors, scientists and WWF.
What a sustainable fishery looks like: the Marine Stewardship Council and the International Pole & Line Foundation — the Maldives one-by-one model as the low-impact counter-example.
The global data baseline: the FAO, The State of World Fisheries and Aquaculture.
Independent investigative work: the Blue Marine Foundation, Follow the Money, and The Outlaw Ocean Project.