One Fish, Two Fish, Deep Fish, New Fish

No fear can stand up to hunger, no patience can wear it out.

—Joseph Conrad, Heart of Darkness

One of the fastest-growing seafood markets is for salmon, and sales of their appetizing, carrot-colored fillets are at an all-time high. Their routine of migrating between fresh and salt water, however, makes these fishes challenging to manage. Wild salmon are caught mostly at the onset of their spawning run, either by seines drawn behind boats or in gillnets deployed near shore. Once the fishes enter fresh water they begin to bloat, gradually spoiling the quality of their meat; to some Indigenous communities, a spawning salmon is categorically inedible once it has quit the ocean. Fisheries managers count fish entering the river mouth and wait until enough have passed—a number based on detailed estimations of current stock size and likely spawning success—to ensure the population will be sustained by their upstream reproduction. When enough salmon have crossed this freshwater starting line, boats and netters in the sea are given the green light. Even then, only a pre-ordained amount of fish can be harvested, approximately equal to the number who will enter the adult population that year. Much uncertainty exists, however, since it is impossible to count all the fish in the sea or determine the exact proportion of juveniles who graduate to adulthood. Estimation is a tricky business, halfway between art and science, but getting the numbers right is critical: catch too many fish, and the population could go bust. Since the collapse of a stock can be catastrophic, catch levels are usually set conservatively. But after the harvest target is decided, one whale-sized question remains: who gets to catch the fish?

For years, fisheries managers would set a simple quota—the total weight of salmon that could be caught in a season—then weigh the landings of each boat as they came to port. When the combined catches equaled the annual allocation, the season was promptly closed. This “total allowable catch” approach was intuitive, but deeply flawed. Fishing captains realized that the faster they landed fish, the greater share of the total catch they could claim. The race to fish was on. Each year, after fisheries scientists set the catch limit and starting date, boats would crew up, gear up, and dash onto the high seas for a “derby” of nonstop fishing. Weighed down by a hold overflowing with fish, seiners wallowed dangerously in northern Pacific waters that could turn ferocious, or deadly, in a matter of minutes. Even today, commercial fishing is one of the most hazardous occupations on Earth: in the first fifteen years of this century more than 700 fishers in the United States lost their lives, a fatality rate nearly thirty times the national average.⁷

Beyond the human tragedy, economic and biological catastrophes also resulted from the race to fish. While some boats, through skill or good fortune, might land hefty catches and earn huge paydays, others would limp into port with holds half empty. Meager paychecks might not cover the immense costs of fishing, from crew salaries and gear repair to insurance and loan payments; bankruptcy and unemployment beleaguered the industry. Meanwhile, overfishing routinely plagued derby fisheries because landings are measured only at port, while boats still at sea might have tons of fish on board, boosting the total catch over the limit. By 1974, nine-tenths of the world’s commercial fish stocks, salmon and otherwise, were drastically overfished, exploited “beyond biologically sustainable levels.”⁸ It was as plain as the horn on a unicornfish’s face. Our system for managing catches was failing, and fishes were disappearing.

To the rescue came a “tentative suggestion” published a year earlier by conservationist and adroit fly fisherman Frank Christy.⁹ Recognizing that “drastic steps” were required to remedy overfishing, he proposed that fishers or boat owners “be allocated a share of the yield from the fishery, expressed as a percent of the catch.” Christy’s tradable “fisherman quotas” were adopted by several Canadian and Icelandic fisheries in the 1970s, including Atlantic herring, and as a national policy by New Zealand in 1986. Soon, individual transferrable quotas (ITQs) would become the most widely used fishery management system in the world, but not without controversy.

At the outset, an initial allocation of shares is established, each representing a fixed percentage of the total catch. Shares are awarded to current boat owners, typically on the basis of their historical catch levels, and give them an exclusive right to land their quota. If you hold a one percent share, and the fisheries department sets the total allowable catch for salmon at 10 million fish, then your boat can catch 100,000. Operators who do not acquire a quota are denied access to the fishery, a painful but necessary side effect of trimming an oversized fishing fleet. The race to fish is now suspended, because each boat can land only its own quota and no more. Captains who come to port with too many fish cannot sell the excess catch and face stiff penalties. Share owners do not own the resource itself—the population of fish—only a right to land a proportion of the annual harvest. Their quota ownership, however, promotes stewardship of the fish and curbs competition with other fishers. Quota shares can be sold between boat owners (the “transfer” part of the ITQ acronym), their value set by the market between buyers and sellers. Fishers whose boats are too expensive to operate will eventually sell their share to other, more efficient operators. Whereas previously an unrestricted number of boats fished furiously for a few days, then sat idle after the annual harvest was exceeded, under an ITQ system a reduced fleet can fish steadily and safely until each boat’s share is landed and sold.

ITQs have generated success and controversy in equal measure. Broadly speaking, those who can hold onto quotas do well. Boats no longer overinvest in gear and crew, fish are landed in better quality, and harvests are more stable, helping push prices higher. Icelandic fisheries of demersal species like cod and haddock saw revenues jump by US$15 million in the first year after ITQs were implemented.¹⁰ But only shareholders are allowed to fish, which limits the number of boats that enjoy the economic revival. In the British Columbia fishery for bottom-dwelling sablefish (Anoplopoma fimbria), for example, a program initiated in 1990 led to the retirement of a third of the fleet. Such limitations on fleet size and fishing effort, plus improvements to efficiency and quality, have helped rebuild fisheries that adopted catch share systems. In one review of early ITQ adopters, twelve of twenty fisheries showed increases in the population size of the target fishes.¹¹ Today more than 100 fish species in the United States are managed through catch shares, like Gulf red snapper (Lutjanus campechanus), whose populations rebounded by 300 percent.¹² In Namibia, an ITQ system was implemented to revive an utterly collapsed hake fishery (Merluccius capensis and M. paradox); after ten years the population had grown by 30 percent, and profits climbed even more.¹³ Globally, the proportion of commercial fish populations that are harvested sustainably, once a distressing 10 percent of all fisheries, has swelled to 65 percent.¹⁴ Much more remains to be done, but ITQs have clearly made a positive impact on the health of wild fish populations.

As with any system of haves and have-nots, it is essential to listen to those who are left behind. In an ITQ system this happens in two ways: either you are unable to obtain an initial share, or you are later forced to sell it. Because quotas usually are applied to fisheries already in decline, there may be fishers who have temporarily retired their boats to wait out the downturn; unfortunately, they can be denied quotas, especially if the initial allocation emphasizes currently active fishers. In some cases, a few in-the-know fishers buy up boats and fishing permits prior to an ITQ’s launch, akin to insider trading, and snare for themselves an outsized number of shares. Such developments have disenfranchised Indigenous people and small-scale fishers, who lack the resources and connections to place a wager on the upcoming system. Still, some ITQ systems do emphasize enrolling Indigenous and artisanal fishers at the outset, to maintain ancestral livelihoods.

Once catch shares are distributed, however, they can be bought by other boat owners and even by people or corporations with no connection whatsoever to the region. Economic downturns that might be shrugged off by a large corporation could be calamitous for a small-scale fisher. When economic hardship strikes, often the most valuable possession in a captain’s household is their catch share. A medical emergency, a newborn son, or a daughter going to college may tempt, or compel, a lower-income fisher to sell their quota. The problem is, prices keep going up, and an artisanal fisher who sells their share is unlikely to be able to buy it back. In Australian waters, when an ITQ system was implemented for southern bluefin tuna (Thunnus maccoyii), an initial 143 shareholders shrank to just 63 after only four years.¹⁵ Little by little, fishery access has consolidated as catch shares of the minnows fatten the portfolios of market whales. Dishearteningly, shares are increasingly amassed by hedge fund managers, rather than boat owners, who view them only as “positive investment vehicles” in byzantine investment strategies, rather than as access rights to a noble profession.

Consolidation of shares into outside hands, especially when fisheries were originally dominated by artisanal or Indigenous fishers, has rightly been met with mistrust, frustration, and fury. In Alaskan halibut fisheries where ITQs and Indigenous rights ran headlong into one another, the native fishers lost. Across forty-four villages on southeastern islands, some two-thirds of boats were decommissioned, 82 percent of quotas vanished, and more than half the people who used to hold shares no longer have the right to fish.¹⁶ Poignantly, this troubling side effect was foreseen by Frank Christy, who had already counseled that “no fisherman could acquire through lease more than a certain percentage of the total yield. This provision would prevent monopoly controls.”¹⁷ Consolidation and loss of Indigenous fisher rights is not inevitable, it should be noted. In New Zealand, where Maori people retain rights to a mere fraction of their native lands (less than 6 percent), they control far more of the sea’s bounty, holding 40 percent of ITQ shares.¹⁸

Despite the gamut of arguments against quotas, and numerous case studies in which rights-based management has fallen short of expectations, one point cannot be denied. Fisheries from the 1970s to the 1990s were failing in their fundamental charge, to harvest fishes while ensuring that future generations would also find fish in the sea. The utter collapse of Atlantic cod fisheries off the eastern shore of North America offers a sobering example of just how badly a fishery can implode, putting thousands out of work, forever. While ITQs are by no means a faultless system, and many improvements are still needed, open-access fisheries are no longer feasible. There simply are too many people buying fish, and too many fishers catching fish, to permit unfettered access to the sea’s fragile bounty.

Today, more than twenty countries rely on ITQs for management of hundreds of fish species. Christopher Costello, an economist at the University of California in Santa Barbara, reviewed more than 11,000 fisheries and confirmed that “implementation of catch shares halts, and even reverses, the global trend toward widespread collapse.”¹⁹ Another study, led by Duke University’s Anna Birkenbach, found that “catch shares slow the race to fish,” and she forcefully underscored a crucial point: “the alternative is no management, which leads to both overfishing and economic waste.”²⁰ Firm supervision of a fishery, via catch shares or other approaches, is essential. University of Washington marine biologist Ray Hilborn evaluated over 1000 fisheries and found that “in regions where fisheries are intensively managed, stock abundance is generally improving or remaining near fisheries management target levels,” and that those fishes are twice as abundant as in weakly managed areas.²¹

Salmon fisheries enjoy management benefits not shared by most fishes, thanks to a simple advantage: they can be counted. When spawning runs begin, salmon pass through narrow, shallow waters at the river’s mouth, where biologists can accurately assess their numbers. Salmon were once fantastically abundant on both coasts of North America, and along Europe’s western shores. But by the late twentieth century, most of those wild populations had collapsed, doomed by inland obstructions and overfishing on the high seas. Today, there are virtually no thriving Atlantic salmon runs in the eastern United States. Even after dam removals and other measures improved Maine’s Penobscot River, for example, just 1000 fish were counted there in 2019.²² Only in Alaska have US salmon runs remained strong, but as those stocks also began to decay, alarm bells tolled. Several decades later, Alaskan ITQ programs have been successful in restoring populations of chinook, sockeye, and coho. Some of the societal outcomes are unquestionably nettlesome, but for now salmon in the eastern Pacific may be spared a repeat performance of their Atlantic cousins’ demise.

While ITQs are capable of saving fish populations from overexploitation and extinction, one thing they cannot do is make more fish magically appear in the sea. To accomplish this, we are moving beyond the harvest of wild animals and turning instead to fish farming and ranching, to the realm of aquaculture.

Farmed Fins

We must plant the sea and herd its animals using the sea as farmers instead of hunters. That is what civilization is all about—farming replacing hunting.

—Jacques Cousteau, The Ocean World of Jacques Cousteau

At the dawn of human history, hunter-gatherer lifestyles gave way to farming when wild lands could no longer support our ancestors’ expanding populations. So, too, have fisheries turned to aquatic farming, to fill the gap between what oceans can deliver up and what people want to gobble down. Aquaculture, which includes saltwater fishes like tuna and salmon, freshwater species like carp and tilapia, as well as shrimp and other crustaceans, oysters and other mollusks, and a lot of edible algae, has seen explosive growth in the last few decades. Aquaculture farms now produce blue foods exceeding all wild-capture fisheries combined, an estimated 135 million tons in 2020 alone.²³ Even after luxuriant harvests of algae are shorn from the total, farmed marine and freshwater species (including shellfish) account for half of global aquatic animal production. Some 600 million people also rely on aquaculture and fisheries for their livelihoods. Blue foods, from ponds and seas, constitute a significant chunk of the world’s agricultural trade, generating annual revenues in excess of US$280 billion.

As far back as 4000 years ago, Chinese aquaculturists were raising fishes in ponds to meet the needs of a settled population far from the sea. Species like carp were, and remain, the most commonly farmed fish: freshwater pens are easier to maintain, carp reproduce obligingly in captivity, and they eat a vegetarian diet readily grown nearby. The first how-to manual on the subject recommended building a large pond with nine islands, stocking it with female and male carp, adding aquatic vegetation, and sprinkling in a few turtles for good measure. “The turtles are heavenly guards, guarding against the invasion of flying predators,” the booklet explains. “When the fish swim round and round the nine islands without finding the end, they would feel as if they are in natural rivers and lakes.”²⁴ Penned more than 2500 years ago, this brilliant handbook was authored by Fan Lee, a former politician whose surname fittingly means “carp.”

A couple hundred years later the Romans were rearing fishes in captivity too, mostly trout and carp, but they also experimented with farming saltwater fishes in lagoons connected to the Mediterranean. Variations on the two approaches, freshwater ponds and saltwater pens, spread across Europe into Africa, and soon the whole world was engaged in some form of aquaculture. By 1987, an estimated 11 million tons of fish and shellfish were being produced.²⁵ A decade later that amount had tripled, and by 2020 reached nearly 100 million tons.²⁶ From ancient beginnings in a pond with nine islands, today’s tidal wave of aquaculture has swept the planet, making commercial fish production the fastest growing food sector on Earth.²⁷ Blue farming has arrived, and it is here to stay.

Some three-quarters of all aquaculture fishes are freshwater species like tilapia, carp, and trout. Of the saltwater one-quarter, however, salmon are undeniably the kings: one-third of all mariculture fishes are Atlantic salmon, some 3 million tons of them in 2020. Also in the top ten mariculture species are coho salmon and rainbow trout (Oncorhynchus kisutch and O. mykiss), each at 200,000 tons annually. Captive salmon are born in laboratories and reared in cold freshwater tanks to mimic their upland nurseries. After a year or so, the youngsters are moved to pens floating in sheltered ocean bays or fjords. Norway, with its abundance of fjords, leads the world in salmon mariculture, raising a third of the global total. Fashioned from heavy netting, a salmon pen is a huge cylinder or cube that hangs from floats; its bottom, also a net, is anchored by cables to the seafloor below. Growing salmon are fed pellets of fish meal blended with soybean and other vegetable proteins. They are, after all, predatory fish and need plenty of protein to flourish.

There is great efficiency in the sea, however, when compared with the land. Because fishes live in a gravity-free medium, their bones need not support as much weight as terrestrial livestock, and their muscle-to-bone ratio is much higher than for a pig or cow. Most fishes also do not maintain a warm body temperature, something that forces livestock to burn additional fuel. Thanks to buoyancy and metabolic advantages, raising 1 pound of farmed salmon requires only around 2 pounds of feed,²⁸ whereas that same pound of ranched cattle will chew through 6 to 10 pounds of grass and feed.²⁹ Salmon aquaculture also generates fewer greenhouse gases than a comparable beef or pork operation, about on par with chicken farming.

As with all agriculture, fish farming must confront an array of challenges if it is to improve sustainability, environmental responsibility, and social equity. Mariculture corrals fishes in high densities, sometimes in the same waters as their free-swimming relatives. Disease can sweep through such crowded pens with terrifying speed and mortality, like the bacterial outbreaks of Piscirickettsia salmonis in Chile (the world’s second-largest salmon producer after Norway). Parasites also invade salmon pens, including blood-sucking copepods known as sea lice that attach to flanks, cheeks, gills, and even eyes. Wild fishes captured near fish pens are often afflicted by the same diseases and parasites. Recently, the government of Canada committed to banning open-pen salmon operations in British Columbia to reduce the spread of these maladies into wild populations. A more creative solution has emerged in the form of cleaner wrasses, who adore plucking parasites from larger fishes. Several wrasse species are being evaluated in Norwegian mariculture operations, and in early trials the 4-inch goldsinny wrasse (Ctenolabrus rupestris) was found to devour more than fifty large sea lice per day.³⁰ Even adding as few as one wrasse per every hundred salmon in a pen was effective at controlling infestations, significantly improving the health of the corral’s silvery livestock.³¹

Little by little we are refining our management of fish farming, in part by better understanding the fishes themselves. New York University biologist Becca Franks has studied salmon captive-breeding operations for years and found the fish can be “highly aggressive towards each other, taking chunks out of each other’s flesh when they’re in their recirculating systems on land.”³² Nobody would have guessed the cause. “At certain phases in their life they’re typically housed in these blue tanks,” Dr. Franks elaborates. “Perhaps not for any reason other than it’s just what they’ve done in the past couple of decades.” But when researchers finally challenged the color scheme, an invaluable discovery was made. “When you give them an option for a different background, their aggression drops to near zero.” During experimental trials in British Columbia, coho salmon strongly preferred black backgrounds, and in these tanks their aggressiveness fell by a factor of four.³³

In another aquaculture project, this time of a freshwater fish in Europe, managers could not induce females to release eggs, no matter how hard they tried. It turns out that all they needed to do was listen to the fish, literally. “They realized at some point that in this species the males vocalize to the females to lead to the spawning release,” Franks explains. “And if you allow the males to vocalize, and you allow the females to hear the vocalizations, they readily would release their eggs … and you could have fertilization within a captive environment.” The staff had been keeping males and females in separate ponds, thus preventing the gentlemen from serenading the ladies. These anecdotes reveal a truth about aquaculture: fish biology, natural history, and welfare all matter. In short, to grow a fish you have to know a fish.

Other pitfalls in aquaculture are more imperceptible than tank color or fish song. Farmed salmon are painstakingly bred for rapid growth in captivity, at the expense of all other concerns. Speed and maneuverability are of secondary interest, as is eyesight, fecundity, and the determination to struggle upstream and mate. But ocean storms occasionally rupture pens, releasing lab-reared fish into the open sea. Once they breed with their wild cousins, the genes of captivity may be passed on, carrying those same shortcomings with unknown consequences for wild populations who very much need speed, maneuverability, good eyesight, and a healthy libido. In Alaska’s Prince William Sound, an estimated 25–30 percent of wild-caught salmon carry genes bred in captivity.³⁴ Farmed salmon also tend to produce fillets with higher concentrations of toxins, such as PCBs and dioxins, than their wild relatives.³⁵ While levels generally remain within European and US safety standards, such findings are prompting concern over the wisdom of eating farmed salmon, the sources of their feeds, and the management of their water and wastes.³⁶

Whether aquaculture is carried out on land or at sea, fish waste poses a significant dilemma. Fish ponds accumulate enormous quantities of feces which are eventually pumped to the ocean when pond water is exchanged. Excessive outflow of nutrients leads to local algae blooms, smothering of bottom habitats, even red tides and marine dead zones. When pens are sited in the ocean, waste accumulates beneath them, as one might expect from a corral holding 200,000 fish or more. Raining from above, fish feces radically alter seafloor habitat, changing the benthic fauna and harming wild fishes who rely on a healthy bottom environment. But the most significant challenge plaguing salmon aquaculture, and farms of tuna, seabass, and other predatory species, is not the pollution that rains out of their cages. It is the food that goes in.

Sardines, anchoveta, herring, and other small schoolers are caught in astounding numbers by encircling seine nets. Every year, more than 10 billion pounds of anchoveta are pulled from South American waters alone.³⁷ The majority of that catch is ground and pressed into fish meal and oil, to be used in animal feeds and fertilizers (continuing an agricultural tradition that began with bird guano 200 years ago). Peruvian anchoveta alone account for about half the worldwide production of fish meal, and a third of its fish oil.³⁸ Much of the resulting animal feed is eaten by terrestrial livestock, household pets, and so forth, but almost half the planet’s fish meal, and three-quarters of its fish oil, are destined for aquaculture.³⁹ Where anchoveta once fertilized the fields of Europe, now they nourish the farms of the sea. Caged carnivores are accustomed to eating fish for dinner, but the use of captured fishes to feed farmed salmon is problematic. Rather than reducing fishing pressure on wild ocean populations, mariculture may simply be shifting overfishing from salmon stocks to anchoveta schools.

Today, anchoveta harvests are only about a third of their 1970s peak: overfishing has taken its toll as demand for fish meal soared in the 1980s and 1990s. Fisheries that target small schoolers are also tested by the deeply cyclical nature of their populations: when upwellings go slack, fewer nutrients are delivered to the surface, and fish abundance plummets. If catch allocations are not adroitly reduced, the fleet can gravely depress the population. In response, Peru imposed rights-based management in 2009, allocating catch shares and compensating or retraining those fishers who left the fishery, about a quarter of the fleet. With fewer boats in the water, overfishing has been reined in, incomes have gone up, and fish meal quality has improved. Furthermore, the fishery has adopted principles of adaptive management, in which real-time assessments of anchoveta abundance are used to set the total catch.⁴⁰ This management system is flexible, allowing catch limits to expand in good seasons, or shrink when waters are less productive. Despite the hardship such fluctuations can impose on fishers, who have to get by with less in lean years, it is the only option for highly variable populations like the Peruvian anchoveta and may ultimately safeguard the fishery against climate change and erratic shifts in life-giving upwellings.

While better management can improve the sustainability of small schooler fisheries, better husbandry of farmed fish can reduce the demand for fish meal. Urged by vocal environmentalists and squeezed by rising feed prices, aquaculture has responded. Today, farmed fishes grow faster with less feed, their food is made with alternative oil and protein ingredients, and fish meal is increasingly manufactured from formerly discarded bycatch and fish-processing wastes. Salmon feeds now use wild-caught fishes for only half their fish meal, as little as 10 percent in some operations, and trimmings (the cast-aside scraps of seafood processing operations) supply a third of the world’s fish meal production.⁴¹ Globally, one pound of farmed fish now requires just a quarter-pound of wild fish in its feed. That fish-in:fish-out metric is higher for salmon and eels but has improved substantially. In 1997 a captive eel guzzled nearly 5 pounds of wild-caught fish meal to produce a pound of farmed eel, today just 3 pounds; meanwhile salmon once gulped more than 3 pounds, nearly double their intake today.⁴²

“Insects to the rescue!” is not a slogan trumpeted by summertime mosquito-slappers, but aquaculturists have been singing the praises of bugs for years. Predatory fishes need protein to grow, and they prefer the taste of fish. But just as alternative nonmeats like Impossible Burger and Tofurky have shown that the public’s palate can be fooled, fish farmers too have turned to alternate protein sources to feed their marine livestock. Formerly an obscure insect of tropical forests, the pint-sized black soldier fly (Hermetia illucens) has grown into a colossal hero for aquaculture. Black soldier fly eggs hatch into larvae called maggots, which feed in the wild on decaying leaves, fruits, and all manner of rotting vegetation. But in commercial insect-rearing facilities they can be served virtually any kind of vegetable food, including compost. In as little as a month, a mountain of compost collected from restaurants, farms, and households transmutes into a seething pile of inch-long larvae which can convert up to 70 percent of the compost into maggot meat.⁴³ And fortunately for aquaculture, farmed salmon love maggot meat. Tests carried out in Norway’s Institute of Marine Research (home to cod-trusting Bjarte Bogstad) proved that salmon grew just as swiftly on feed prepared from black soldier fly larvae as from fish meal, and the resulting fillets were identical in nutrition and flavor.⁴⁴ If scaled up, insect factories could digest much of the world’s organic waste into feed for farmed predatory fishes, while also relieving the overfishing pressure on wild small schoolers like anchoveta.

Corralling the Tiger

Mediterranean sardines, like their South American anchoveta cousins, swim in immense schools and are seined in vast numbers, frequently destined to become fish food. So heavy is their overfishing that so-called common dolphins (Delphinus delphis), who rely on wild sardines as a prime food source, are now downright rare. All those sardines are being harvested for a single purpose: to feed captive tuna as they are fattened for market. Tuna are so staggeringly valuable, to diners and to fisheries, that many attempts to rescue their dwindling populations have been defeated by the power of the dollar and demand of the dinner fork. Wild tuna are often caught using baited longlines, despite the appalling levels of bycatch (a polite word for collateral damage) snagged by this indiscriminate method, including sea turtles and toothed whales. Advances have been made, however, by using weights to sink the longline hooks below typical turtle depths and limit their bycatch.⁴⁵ Nets also encircle schools of tuna when they can be found, by spotter planes or by taking advantage of tuna’s penchant for swimming under pods of spinner and spotted dolphins. In the 1960s, San Diego tuna boats began setting nets on dolphin pods and killed an estimated 4.8 million dolphin between 1959 and 1970.⁴⁶ In one of the earliest public movements to protect oceanic wildlife, outraged citizens rose up in protest, and in 1972 the Marine Mammal Protection Act made it illegal to harm whales and dolphins in US waters. Expanding their reach, environmental groups and consumers made a global push for dolphin-safe tuna and have succeeded in changing an industry. Today more than 800 tuna companies in the United States and beyond, including 95 percent of canned tuna, adhere to dolphin-safe standards.⁴⁷ Among other advances that have been won, purse-seining boats can no longer intentionally set on dolphins, and they are required to “back down” their nets, leaving an explicit escape route. Public protest remains a powerful tool to compel change.

As a result of increasingly sophisticated fishing operations, however, and swelling desire for top-dollar seafood, catches of most species of tuna have been declining for years. In 2019 alone, fishing fleets landed over 6 million tons of tuna; mackerel and other tuna-like relatives raised that total to 9 million.⁴⁸ Sadly, more than 40 percent of commercial tuna stocks are being harvested beyond biologically sustainable levels. The largest tuna species are so heavily hunted that all are listed as threatened or endangered. In the case of southern bluefin tuna, an estimated 95 percent of its population has already been fished out.⁴⁹ Still, there is cause for optimism: about 10 percent of tuna stocks are actually increasing, due to smarter management and firmer control of fishing pressure.⁵⁰ Skipjack, boasting the highest reproductive rate of any tuna, has yielded stable catches around 3 billion pounds annually, making it the third-most harvested fish species for eleven straight years.⁵¹

In response to shrinking tuna populations and rising consumption (or at least rising prices), tuna ranching has galloped onto the scene. In a typical ranching operation, juvenile tuna are caught in the open ocean, transferred to a cage of netting, then towed to the mainland. When the cage reaches nearshore waters sheltered from storms and swells, they are transferred to a permanent ranching pen, a hockey puck–shaped cage some 150 feet across and 30 feet deep. Inside, the tuna are fed twice a day for up to eight months, until their weight doubles. Food consists of a mixture of raw and frozen baitfish, commonly sardines captured in the waters of the Mediterranean and beyond. Ranching of bluefin tuna alone, an aquaculture target thanks to the lofty prices they command, yielded a whopping 28,000 tons in 2018 worth a jaw-dropping 1 billion dollars.⁵²

Tuna ranching is plagued with problems, however, and while some of the current challenges have solutions at hand, others are only a glimmer on the horizon. Whereas aquacultured salmon can be bred from eggs in a lab, tuna ranching depends on young tuna captured in the wild. Because those fishes are not landed at a seafood processing dock, they often are not registered nor counted against fisheries catch limits, hampering managers tasked with setting sustainable catch levels. Furthermore, tuna taken from the sea at a young age are robbed of the chance to reproduce. Targeting youngsters therefore is a double hammer blow, removing current fish from the population and blocking future fish from hatching.

To address this dilemma, researchers in Japan and Europe are laboriously studying every aspect of tuna reproduction. By controlling water temperature and light levels while simultaneously manipulating hormones, they have succeeded in rearing tuna from eggs entirely in captivity.⁵³ If their experimental technique becomes standard across tuna ranching, the possibilities are staggering: a single bluefin female weighing about 200 pounds is estimated to produce 9 million eggs in just one spawning event.⁵⁴ If just one in a hundred of those eggs could be fattened up to the size of the mother, the resulting 9000 tons of tuna would exceed the annual bluefin catch of the nation of Japan.

Still, fattening a captive tuna requires prodigious amounts of food. Tuna’s hot-blooded bodies burn a lot of energy just to stay warm, far more than a cooler-blooded salmon: a bluefin tuna requires about 15 pounds of feed to put on a single pound of flesh, seven times more than a salmon.⁵⁵ Unfortunately, switching to insect larvae–based food is not an option, as tuna turn up their snouts at any meal but fish. Much will have to be done if the growing tuna ranching industry is to avoid starving the seas to fatten the livestock. In 1995, one southern Australia sardine fishery collapsed precisely because of overharvesting for tuna ranches: in a single year of overfishing, sardine numbers plummeted to a mere quarter of their former abundance.⁵⁶

Like salmon, tuna held in dense captivity also suffer high rates of parasitism and disease. Sea lice are perhaps the most troublesome pests. In captive tuna, it is not uncommon to find one type of sea louse (Caligus chiastos) attached to the eyes where they gnaw at the cornea, damaging the keen vision on which a tuna relies for hunting.⁵⁷ Infestations can be extreme: Craig Hayward and his Australian colleagues studied southern bluefin enclosures and found three-quarters of the penned fish were infected, with a skin-crawling average of 265 lice spiked to each fish.⁵⁸ Heavy infestations, if left unchecked, can cause tuna to waste and die after just a couple months in a ranching pen. This particular louse has an alternate host, a scavenger fish called Degen’s leatherjacket (Thamnaconus degeni) who feeds on the scraps and waste that accumulate beneath the crowded pen.⁵⁹ The lice are thus perfectly poised to leap into action as soon as a new herd of tuna are corralled and infect the entire group. Infection levels can be reduced, though, by shifting the pens into deeper waters and limiting overfeeding, actions that reduce the excess food accumulating under the pen so leatherjackets (aka lice launching pads) no longer congregate.

Cramming hundreds of tuna into a ranching pen can damage not only their well-being, but also the health of the environment nearby. Beneath and around the cages, dense snowstorms of falling food, scales, and feces have significant impacts. Even studies commissioned by the Tuna Boat Owners Association in Australia revealed harmful impacts on the seafloor up to 500 feet away from the pens.⁶⁰ As nitrogen and phosphorus-rich wastes fall from pens, they settle on the bottom at rates fourteen times higher than are found in nature.⁶¹ Dense fish farming operations risk triggering eruptions of algae, disease, and dead zones around their cages. These effects are made worse by the relative calm of inshore waters; farther out to sea, currents carry away more of the waste and dilute the cage’s effect. On the other hand, moving pens to deeper waters leaves them vulnerable to lashing storms, and at greater risk of catastrophic failure.

Seafood buyers and sushi lovers may just have to accept some fundamental limits of eating the largest of the ocean’s top predators. Tuna are fast moving, far ranging, have a searing metabolism, and require vast amounts of prey fishes to reach adulthood. History has shown that they endure only modest annual harvests. While smaller species like skipjack and albacore can tolerate the predations of a robust fishery, the true kings of the sea—bluefin and bigeye—may never withstand more than the lightest of fishing pressure. Though the supply may be augmented by production from aquaculture operations, restrictions on the capture of food fishes must, for the moment, limit the scale of those ranches. Big tuna, like lions and tigers and bears, may just be animals that are better admired in their native waters than dispatched to a dinner plate.

Too Much of a Good Thing

Atlantic cod (Gadus morhua) was for many years a mainstay of Indigenous peoples in North America, and new arrivals from Europe, but the bounty did not last long. A few centuries after English settlers established themselves on the shore, Canadian and American cod stocks had wholly collapsed. Why did this happen? The answer is the same around the world: too many boats and nets, buoyed by government incentives, are chasing too few fish. Economists have a word for this imbalance, overcapitalization, and its effects have been devastating. A global analysis led by renowned fisheries biologist Boris Worm (and man most likely to lend his name to the next James Bond villain) estimated in 2012 that two-thirds of marine stocks were being fished beyond their capacity to recover. Incredibly, more than 100 of them faced fishing pressure ten times higher than their sustainable target.⁶² His frequent collaborator Daniel Pauly asserts that the global fleet is double or triple the size that fish stocks can bear. Government support of this fleet is unbending, despite fisheries making “a miniscule contribution to the GDP of advanced economies—in the United States, even less than that of the hair salon industry.”⁶³

In part to sustain the employment historically provided by fishing, nations continue to prop up fisheries. “The world’s governments provide over US$30 billion in subsidies each year,” writes Pauly, “about one-third the value of the global catch.”⁶⁴ That is a shocking statistic, and it is difficult to imagine another industry that could rely on governmental support equal to a third of its revenue. But fishing has always been a noble occupation, and it holds a soft spot in our collective heart—otherwise known as a blind spot that obscures the judgment of industry and government. In the case of cod in the western Atlantic, it was a blind spot that led to permanent closure of a once-booming fishery. Boat owners, crew members, fish buyers, and government representatives refused to accept that the cod fleet was far too large, and nobody had the courage to take the first step back from the precipice. So, over the cliff went the entire industry, never to return.

Overcapitalization is rampant in world fisheries. Subsidies to the North Atlantic fishing industry alone add up to over US$2.5 billion per year. Those free dollars encourage new boats to enter a fishery, and ageing boats to remain active, even after fish populations are overtaxed. Profligate subsidies also undermine cooperation, as fishers in the same fleet view one another as rivals to be outspent rather than as partners with whom fishes must be justly shared. In 2021, a group of nearly 300 scientists from forty-six countries published a challenge to the World Trade Organization, urging that “WTO members must prohibit fisheries subsidies.”⁶⁵ The authors highlighted the threat posed by foreign fleets, which exploit weaknesses in international treaties governing the high seas to flaunt national management regulations. “Subsidies to distant-water fishing fleets,” they railed, “threaten lower-income countries that rely on fish for food sovereignty.” Even worse, some of those fleets subject their crews to abysmal wages, appalling work conditions, forced labor, and shocking abuse; they have rightly been accused of modern-day slavery.⁶⁶

Auspiciously, the WTO passed a historic agreement in 2022, with all 164 members agreeing to prohibit “fisheries subsidies that contribute to overcapacity and overfishing, and eliminate subsidies that contribute to IUU [illegal, unreported, unregulated] fishing.”⁶⁷ The WTO manifested commendable empathy to developing nations, noting that “improving the sustainability of fisheries is critical … especially to the millions of mostly poor people who make their living by fishing.” Hard work remains: two-thirds of member nations must ratify the agreement, negotiations to protect fisheries in developing countries must be concluded fairly, and subsidy-free fleets across the globe must adapt to new financial realities. Shrinking a fishing fleet puts captains and crew out of work, along with a network of associated laborers, while retraining programs and boat buybacks only partially offset the hardship. But if the bitter prescription of eliminating subsidies can be swallowed, it could finally cure a syndrome of overcapitalization that has plagued fish and fisheries for more than fifty years.

If fishing pressure is restrained, cod and other demersals can provide a sustainable source of food for the world, and a steady source of income for coldwater fishers. Countries like Norway have solved many of the core problems, and their carefully managed fisheries appear healthy. Today, cod and haddock and hake constitute 10 percent of the world’s aquatic export market, a robust share that can be maintained for years as long as appropriate measures are taken.⁶⁸ Management of northern Pacific schools of haddock, halibut, and others has been admirably successful, according to the Food and Agriculture Organization, although salmon are singled out for some declines in Canadian and Californian waters. “Most species except salmon stocks in this region are healthy and well managed, primarily due to science-based advice … and to good governance that has helped reduce fishing pressure from distant water fishing nations.”⁶⁹

Even when fishing pressure is reined in to match the productivity of slow-growing fishes like cod, the gear used to catch them can cause long-term damage. For demersal fishes, the invention of the otter trawl was once a brilliant idea. Dragging a net along the seafloor was a surefire way to capture fishes that hugged the bottom. But cameras on remote submersibles have shown the extent of the devastation caused by bottom trawling. In many regions, such trawlers rake a single patch of seabed dozens of times each year. There is no chance for the essential elements of healthy habitat to recover, a protracted process that can take years, and soon there is nowhere for fish to forage, dodge predation, court, and breed.⁷⁰ All too quickly, life-sustaining sea floors can be converted into biological deserts, evicting demersal fishes from their seafloor homes. The ecological collapse also releases approximately 1 billion tons of planet-warming carbon dioxide every year, equivalent to the entire aviation industry.⁷¹

Bottom trawling is particularly problematic for artisanal fishers, and nowhere is this more evident than in tropical waters. There, small-scale fishers have for years earned an honorable living from their boats, nets, and hooks. But when industrial trawlers begin assaulting the ecosystem, dozens of species suffer, and artisanal boats come to port empty. One reason is that marine productivity in tropical waters drops off steeply with depth: near to shore, the sea is full of life, but sail just a few miles out and the waters are largely empty. This abrupt gradient encourages trawlers to ply their nets very close to the coast, precisely in the waters that artisanal fishers have used for centuries. Clashes inevitably occur, of the David versus Goliath variety. In Indonesia, an uproar of violence and protest prompted the federal government to ban nearshore trawling throughout the archipelago. Although the trawlers yielded huge catches of shrimp, invaluable to a developing nation hungry for seafood export income, they were catastrophic for artisanal fishers. Shortly after the ban went into effect, small-scale fisheries rebounded dramatically, and lost fishing employment was revived.⁷²

In warm, shallow waters around the world’s tropics, coral reefs, seagrass beds, and mangrove fringes have sustained small-scale fishers for millennia. But rapid growth of coastal communities is now weighing on tropical seas. Displaced farmers from interior lands often migrate to coastlines, where fish ostensibly are easily caught for dinner. Entry of large numbers of untrained fishers into a small fishery, however, can be disastrous. While the responsibility does not fall to the landless individual, but rather to the global market forces that displaced them, the effect on the ocean is the same: too many hooks for too few fish. And not only hooks are employed. Whether due to desperation or to avarice, tropical waters have been assaulted by scandalous forms of fishing, including lobbing dynamite or even cyanide into the water. Such methods are indiscriminate, killing large numbers of nontarget species, and they have been responsible for the near-total destruction of reefs around Jamaica and other tropical sites.

Unfortunately, in developing nations we often do not know how many hooks, nor how many fish, are involved in a fishery. For a wide range of systemic reasons, reporting of fish harvests is spotty in many tropical countries, which handcuffs proper fisheries management. Dirk Zeller of the University of British Columbia studied the artisanal harvests of American Samoa in the 1980s and 1990s and estimated that true catches were seven times larger than reported in official statistics. Furthermore, their contribution to the local economy was an astonishing nine times larger than reflected in government ledgers.⁷³ With this degree of underreporting, accurate monitoring and management of tropical fishes, and their benefits to local fishers, can be as murky as squid ink. It is nearly impossible to administer a fishery in the dark, especially when those who most need the livelihood—artisanal and small-scale fishers—are underrepresented or absent from official records.

Even with accurate assessments, applying fisheries management tools developed in the temperate zone to the peculiarities (and delights) of tropical waters can be challenging. ITQs, for example, are predominantly designed to manage single-species fisheries. But tropical waters are gloriously rich in species, the very reason they are revered by snorkelers and scuba divers. Management systems must be adapted to handle fisheries that catch many species at once, and even the loudest of cheerleaders admit ITQs are a tool that does not apply well to tropical multispecies fisheries. When poorly managed artisanal and unregulated commercial fishing collide, it is the ocean’s creatures who suffer most. By some estimates, fish abundance in tropical Asian countries is now less than 10 percent of historical levels, thanks to mismanagement and overfishing.⁷⁴

The solution to overfishing, according to fishers, community members, and conservationists, will involve a combination of gear restrictions, catch limit enforcement, but also meaningful stakeholder participation. Old models of top-down fisheries management, with remote scientists setting catch allocations and governments handing out quotas, evoke disturbing reminders of painful colonial legacies. Moreover, such models often do not help sustain fish populations nor support the livelihoods of fishers. Instead, advocates of a bottom-up approach, like Vandick Batista of the Federal University of Alagoas in Brazil, recommend “engaging stakeholders, especially those that are involved in the day-to-day use of a resource, such as artisanal fishers and their families.”⁷⁵ Approaches to participatory governance as diverse as the fishes they manage are being trialed in countries throughout the tropics. Central to their success is acknowledgment that input from local fishers must be sought long before gear and catch limits are implemented, and that cooperation must be emphasized throughout the process. What is referred to as an ecosystem management approach, something that pairs well with the flexibility of adaptive management, works best when it accepts that ecological, social, and economic fluctuations are bound to occur. In Batista’s words these advanced systems, “more fully embrace the inherent uncertainty and complexity of both the fisheries and the communities that exploit them.”

Sanctuary in the Sea

One touch of nature makes the whole world kin.

—John Muir, Our National Parks

As developed and developing nations make demonstrable progress toward improved fisheries management, it remains evident that achieving sustainable ocean stewardship on a global scale will require a mosaic of solutions. One key piece of the marine conservation puzzle is a protective measure dating back to John Muir and the establishment of the US National Park System. Setting aside land—or water—is critical to preserving diversity and abundance in sensitive habitats. The most effective tools we have in the struggle to save the seas are marine protected areas, and the United Nations recently set an ambitious goal of placing 30 percent of the marine realm into protected areas. Currently the United States has enrolled a quarter of its seas,⁷⁶ but the standout leader is Australia, where nearly half of national waters fall within marine protected areas.⁷⁷ The planet, however, has some work ahead of it: just 8 percent of the world’s oceans are currently protected, and assigning seas to a marine reserve does not automatically constitute a guarantee that those waters are fully safeguarded.

Marine protected areas (or MPAs) bestow a diversity of benefits so broad that resistance to their establishment is receding like an outgoing tide. Currently, the main opposition comes from what Daniel Pauly refers to scornfully as the “fishing-industrial complex,” an echo of outgoing US President Dwight D. Eisenhower’s warning about the outsized power of the military-industrial complex.⁷⁸ The former president’s words, uttered in 1961, were prescient and apply just as well to the fisheries of today: “we—you and I, and our government—must avoid the impulse to live only for today, plundering, for our own ease and convenience, the precious resources of tomorrow.”⁷⁹ Industrial fishers often oppose marine protected areas since they view them as closures of former fishing grounds. This is usually true, because protected areas tend to be enacted in locations with high fish abundance, diversity, and productivity: precisely the spots where boat captains would like to fish. But the benefits of closing down those sites outweigh the lost harvests. Marine protected areas offer vital refuges and usually enhance fisheries and local economies by ensuring fish live longer and grow larger, amplifying reproduction (often immensely), exporting juveniles who recharge harvested populations nearby, and establishing tourism destinations that yield beneficial new sources of revenue.

Marine protected areas have a long enough history to assess their contribution to maintaining healthy oceans. More than 1600 protected areas have been inaugurated in US waters alone, including the tongue-twistingly named Papaha¯naumokua¯kea National Monument north of Hawaii which encompasses nearly 600,000 square miles. Within its safeguarded waters, fishes like bird-nabbing giant trevally, graceful silky sharks, and hundreds more enjoy a respite from fishing vessels that pursue them elsewhere on the high seas. Around the globe, a flood of MPAs have been declared since the 1970s, more than 11,000 sites and counting, including ten massive reserves each covering over 100,000 square miles.⁸⁰

Marine protected areas, particularly those that include no-take zones where all extractive activities are prohibited, are good for both fishes and their habitat. Within reserves, seafloor environments recover more swiftly, even after trawling.⁸¹ Fishes and other marine life increase in number and size, as does their diversity. A review of 124 reserves around the globe, coordinated by Sarah Lester from the University of California, revealed that biomass within reserve borders swelled to five times that of pre-establishment levels.⁸² In some cases the gains were extraordinary. Large predatory fishes including snappers and groupers were a remarkable twenty-eight times more abundant in the Philippines’ Bongalonan Reserve. In the Governor’s Island reserve of Australia, rock lobsters (made famous by the B-52s hit song) were twenty-three times more plentiful. Perhaps of greatest importance was Lester’s confirmation of the so-called “spillover” effect, whereby animals that reproduce within the shelter of a marine reserve eventually disperse, revitalizing populations in nearby waters and sustaining fishery harvests. Biomass in sites lying beyond reserve boundaries nearly tripled after protections were put into place, and animal densities doubled, benefiting both fish and fishers. In the Caribbean nation of St. Lucia, even modest-sized marine reserves promptly lifted catches by artisanal fishers in nearby waters by 46–90 percent.⁸³ Back in Hawaiian waters around the world’s largest no-take reserve, spillover has boosted yellowfin tuna catches by 54 percent, showing that even highly mobile predators benefit from marine reserves.⁸⁴

One of the most significant contributions of marine protected areas is made by females who call them home, or more specifically, by their eggs. Fishes of both genders grow significantly bigger within a reserve, where the abundance of large fishes can increase tenfold after establishment.⁸⁵ Outside the reserve, the heftiest individuals are usually prime targets for fishers because they command the highest prices, and because fisheries management is often structured around minimum-size limits. But catching large fishes, especially large females, can drastically impair a population’s capacity to reproduce. Big females produce more eggs, so landing the largest individuals removes the best breeders. The relationship between female size and egg production can be mind-boggling: a single 24-inch red snapper (Lutjanus campecheanus) carries over 9 million eggs, more than could be deposited by a team of 200 females each 16 inches in length.⁸⁶ The vast productivity of large fishes is one of the key shortcomings of size-based management, but the bounty of eggs they release into the sea is an outsized advantage of marine protected areas.

Like many solutions, marine reserves are not a perfect remedy for all problems. They can be costly to implement, their establishment may be met by opposition, and their placement may inadvertently favor certain fishers over others. As climate change warms the oceans, fishes are shifting their distributions and may permanently migrate beyond a fixed boundary. Variations in reserve size, degree of protection, pre-establishment degradation, nearby fishing pressure, and other circumstances can also temper their effectiveness. In the northwest Mediterranean, for example, the Medes Islands MPA has shown mixed outcomes. Established in 1983, six of the reserve’s fish populations have been surveyed annually for nearly twenty years.⁸⁷ Five of them, all heavily targeted by fishers, have steadily increased in abundance, though it may take up to thirty years for their numbers to fully recover. Gilthead seabream (Sparus aurata), a delectable porgy who favors seagrass beds, sadly has not recuperated. An initial recovery stalled, likely because fishers were targeting spawning areas unfortunately located near the reserve’s border. Judicious expansion of the reserve would seem to be called for. Marine reserves that are too small, or that suffer from inadequate monitoring and enforcement—a direct result of underfunding—often show fewer and weaker benefits than larger and better protected areas.

In the Caribbean nation of Belize, Glovers Reef Marine Reserve spans more than 30,000 acres (about 50 square miles) of turquoise waters and rich coral reefs. By the mid-1990s a large no-take zone had been established, but monitoring is chronically underfunded. While the resident population of Caribbean reef shark (Carcharhinus perezi) remained stable from 2000 to 2013,⁸⁸ parrotfishes gradually became more scarce.⁸⁹ Recovery of these colorful coral-eaters may have been hampered by algal overgrowth, which built up during years when overfishing decimated herbivorous fishes who normally keep algae under control. Researchers from the Smithsonian Institute who conduct regular studies in the reserve suspect both legal and illegal fishing are hampering the reef’s revival (artisanal fishing is still permitted in broad zones).⁹⁰ Shark conservation studies in Australia underscored that no-take zones, where fishing bans can be challenging to enforce, are outperformed by no-entry zones that strictly prohibit boat traffic of any kind.⁹¹ Despite parrotfish declines in Belize, however, tourism to Glovers Reef has soared, bringing much-needed revenue to a country with the smallest economy in Central America.

The world-famous Galápagos Islands are encircled by an enormous marine reserve covering some 50,000 square miles of Pacific Ocean, a watery expanse nearly impossible to adequately police. National and distant-water fishing vessels sit on the reserve’s border waiting for tuna to cross, a (legal) tactic known as “fishing the line.” According to Jorge Ramírez, fisheries biologist with the Charles Darwin Foundation, fishers from mainland Ecuador (to which the islands belong) are increasingly supportive of the reserve. “Right now the tuna fishers are more aware about the importance of the Galápagos Marine Reserve,” he explains, “they understand the reserve is like a nursery for tuna … and they declared publicly the importance of the Galápagos reserve.”⁹² Distant-water fleets, however, are another story. When a school nears the border, disreputable boats may switch off their satellite tracking systems, meant to control incursions, and sneak into the reserve. In 2017 a Chinese vessel emblazoned with the overly long name of Fu Yuan Yu Leng 999 was nabbed by the Ecuadorian coast guard. Inside they found more than 300 tons of fish taken illegally from the reserve’s waters.⁹³ Worse, critically endangered scalloped hammerhead sharks (Sphyrna lewini), who travel to the waters of Galápagos to breed, made up most of the illicit catch.

For organisms that tend to stay put, a marine reserve can be a fabulous place to live. Highly mobile creatures like sharks, however, are more difficult to conserve. To find food, especially in an increasingly depleted ocean, they must travel great distances, wandering in and out of reserve boundaries. Sharks are particularly at risk, since a vigorous market in Asia for shark fins has painted a target on the backs of these magnificent animals. Vast smuggling networks have sprung up to move dried shark fins illegally across borders, often the same networks that traffic illicit tropical timber, weapons, drugs, and even human beings. So valuable are the fins that they are frequently sliced from the shark while still on the high seas, the body then dumped overboard to hide the evidence. Fortunately, a strong alliance to denounce shark finning has emerged between marine conservationists and Asian business leaders. No longer is shark fin soup considered standard fare for weddings, especially among younger couples, and the purchase of fins is increasingly reviled. Despite the exceptional mobility of sharks, marine protected areas located sufficiently far from fin marketplaces (800 miles or more) have been shown to effectively protect them from slaughter.⁹⁴

One nation has gone so far as to ban shark fishing entirely. As one of the world’s foremost destinations for snorkelers and scuba divers, the Republic of Palau believed there was greater value in viewing undersea wildlife than in harvesting it. Economic analyses in 2010 revealed that shark diving generated an estimated US$18 million every year, nearly one-tenth of the country’s gross domestic product.⁹⁵ Much of the proceeds go directly into local salaries and domestic tax revenues. Conversely, if all those sharks were harvested and sold, the earnings would total a paltry $10,800. Palau has long practiced a fishing management strategy, rooted in Indigenous wisdom, that sets aside large areas for spawning. The shark fishing ban was viewed as an extension of that philosophy, known as “bul.” Now a no-take zone covers 80 percent of Palau’s waters, nearly 200,000 square miles of ocean, an area larger than France; local fishers retain access to the remaining 20 percent. President Tommy Remengesau, Jr., explained the true meaning of bul: “It is prohibition in the sense that you’re doing this to benefit your children, because you have to think about tomorrow and the day after and the years coming.”⁹⁶

Comparably huge marine reserves like Australia’s Great Barrier Reef have also shown that tourism revenue can compete with the sums generated by fishing. Visitors to the Great Barrier Reef support some 64,000 jobs, making the sector one of Australia’s largest employers.⁹⁷ Around the planet, coral reef tourism contributes some US$36 million to the world’s economy.⁹⁸ That income may be just a blenny-sized fraction of the revenue of global fisheries ($151 billion in 2020), but when all types of coastal and marine sites are included the figure jumps like a marlin.⁹⁹ In Europe alone, this blue tourism generates an estimated $180 billion per year, and employs more than 3 million people in meaningful, safe, and rewarding careers.¹⁰⁰ Whether large or small, marine protected areas have shown undeniable success at achieving a trident of goals. They can protect wild fishes and their habitats, provide solid sources of local employment, and guarantee the future of fisheries, for tomorrow and the day after and years to come.

Sea of Confusion

How do you know what you are eating? On land, this is a pretty simple question: chicken looks like chicken, beef tastes like beef. But when it comes to seafood, it is discouraging how frequently fraud and impersonation are perpetrated. The label on a fish you buy at a seafood counter or seaside market may bear little relationship to the fish you are about to eat. By some accounts, as much as one-third of seafood sold in the United States was mislabeled.¹⁰¹ Another study suggested this number may be as low as 8 percent,¹⁰² while still a third investigation tested sushi sold in Los Angeles restaurants and found nearly half of the fish was mislabeled.¹⁰³ In some cases, mistakes in handling and shipping can lead to honest labeling errors; in others downright fraud is being committed to dodge import bans, mislead investigators, or overcharge buyers. Regardless of the cause, the result is the same: consumers may inadvertently finance disreputable fisheries while trying to support sustainable sources. Mislabeling can be particularly damaging to wild populations because the fishes substituted for well-known species most often come from fisheries whose cheap prices reflect shoddy, short-sighted management that perpetrates overfishing, habitat damage, and high bycatch.

Sharks and deepwater species are mislabeled with disturbing frequency. Shark meat is often sold in South Africa under the vague moniker of “ocean fillets,”¹⁰⁴ and in Greece more than half the shark meat samples identified by DNA barcoding were labeled as other, less objectionable fish species.¹⁰⁵ Orange roughy was the recipient of a deliberate rebranding campaign (changing the name from slimehead), but other fishes of seamounts and the deep sea are fictitiously renamed in an effort to boost their marketability. This practice is fraught, since such fishes are often exceptionally slow to reproduce and cannot withstand more than very light fishing pressure. Patagonian toothfish (Dissostichus eleginoides) is now listed on menus as Chilean seabass, though it is not a bass but rather inhabits deep waters near the Antarctic ice shelf. Another popular restaurant item is marketed as monkfish but properly known as a goosefish (Lophius americanus) for its homely, even terrifying appearance.

If diners do not know what they are eating, they do not know what fishery they are financing. Absent this information, consumers cannot vote with their dollars for fisheries that are sustainable, whose fish stocks are not overexploited, whose gear does not damage habitat or ensnare bycatch, and whose fishers enjoy stable income and decent working conditions. To provide such data, independent certification systems now evaluate fisheries on behalf of buyers. A number of options exist, but the most prevalent—and sometimes the most controversial—is the blue checkmark label of the Marine Stewardship Council (MSC).

Brian Perkins spent six years as the MSC’s regional director for the Americas, retiring in 2021. A native Mainer, his voice betrays occasional traces of New England as he relates his personal introduction to the seafood industry, on the Icelandic island of Grímsey. “I landed as a hitchhiker backpacker, then twenty-one years old, and in the summertime went up to see the midnight sun.”¹⁰⁶ Remote and tiny, Grímsey is home to a hardworking fishing community, which Perkins joined. “One of the boat owners asked me if I wanted to work on his fishing boat that winter, and I agreed.” About his lack of preparation, he confesses, “I don’t come from a fishing background at all.” With endearing understatement, he recaps the challenge of working in Iceland’s stormiest months: “it was an interesting experience to fish on a 35-foot wooden boat on the ocean in the wintertime.”

Founded in 1996, the Marine Stewardship Council is, in Perkins’ words, “the gold standard” of sustainability certification. Fisheries seeking the blue checkmark label undergo a rigorous assessment process that lasts a year or more, testing their performance against twenty-eight indicators of stock status, habitat impacts, and fishery management. Evaluations are conducted by third-party assessors, paid by the fishery itself. The MSC may grant immediate certification, as was the case with well-managed fisheries in Norway and Iceland. “Think of us like the Good Housekeeping seal of approval … of the good job that the fishers and the management are doing.” Or a conditional certification may be offered if the fishery is not yet up to par but shows improvement on the indicators. “One of the things that does is rather than only being able to certify the very best fisheries, we are able to certify fisheries that are doing a very good job but have a few areas that need improvement, and this provides the incentive and the encouragement to improve.”

An example comes from South Africa, where a small fleet fishing for shallow-water hake (Merluccius capensis) applied for certification. “There were five vessels that wanted to sell into the European marketplace,” Perkins explains, “and in order to do that they needed to get certified because the European market is quite particular about only selling MSC certified fish.” Bycatch, however, was a serious problem. “That fishery, when it went into assessment, was killing about 20,000 seabirds a year in bycatch. And that is obviously not a sustainable practice. A chunk of those birds were albatross, which is particularly endangered.” At the MSC’s urging, the fleet consulted with the nonprofit BirdLife International, which recommended adoption of tori lines, “basically long nylon streamers that stream off the stern of the boat and prevent the birds from getting to the hooks while they’re still on the surface.” The streamers worked and spread through the industry. “They reduced the bird bycatch from 20,000 to 200 by using that system,” Perkins proudly reports. “South African fisheries management, looking at those five boats that were using the tori streamers, made it mandatory on all longline vessels.”

MSC certification opens the door to new and larger markets and allows seafood buyers to support a sustainable fishery which can then charge more for its fish. In this they resemble the Forest Stewardship Council, whose certification of responsible timber operations gives consumers of wood and paper the opportunity to put their money where their hearts are and reward well-managed suppliers. In the United States, companies like Kroger, Whole Foods, Walmart, and Target promote the sale of sustainable fish; in the Netherlands, more than 85 percent of all fish sold is certified.¹⁰⁷ Ideally, the certification should allow fish buyers—from individual shoppers to restaurant buyers to commercial distributors—to check whether a fleet, no matter where they operate, is fishing conscientiously and then decide whether to pay a higher per-pound price for that sustainability. Currently more than 80 percent of US fishery landings are MSC certified,¹⁰⁸ while 15 percent of the globe’s wild marine catch has netted the seal of approval.¹⁰⁹ US numbers can be a little misleading, though, since the majority of fish caught in the United States is shipped overseas,¹¹⁰ while paradoxically the preponderance of the seafood eaten by Americans is imported.¹¹¹

Despite the MSC’s noble aims and significant achievements, facets of the certification process have rankled marine conservationists. The nonprofit is funded by donations, but also from licensing fees paid by fisheries to display the coveted blue label. Some argue this arrangement creates an incentive to certify substandard fisheries so the MSC reels in more income. Others have objected to the organization’s certification of fisheries using damaging gear, like bottom trawlers. Perkins defends the practice, suggesting that such gear can be employed under strict conditions. “We have a number of trawl fisheries that are certified. Some of them take place on sandy bottoms where the impact is minimal. Some of them are in places if they get into a sensitive environment they have ‘move on’ rules. So if the trawl pulls up a piece of deep water coral … they agree to avoid that area.”¹¹² Even sandy sea floors, however, can be home to diverse and vulnerable invertebrate communities, and remote submersibles have documented damage where an MSC-certified fishery trawls for Greenland halibut (Reinhardtius hippoglossoides).¹¹³

Other fishing techniques with poor track records have also been certified. The organization awarded their checkmark label to several tuna fisheries that rely on floating aggregation devices, despite the distressing bycatch of this tactic, estimated at five times greater than in the open sea.¹¹⁴ When it comes to deepwater fishes, like the Chilean seabass (née Patagonian toothfish), marine biologists argue that we lack data fundamental to assessing the fishery. Jennifer Jacquet, professor of environmental studies at New York University points out, “nothing is known about this fish: no eggs or larvae have ever been collected.”¹¹⁵ In this case, market opportunity rather than demand seems to be steering the ship. “One guy starts catching them, starts experimenting with cooking them,” Dr. Jacquet narrates, before swatting aside the fallacy that all fisheries are helping feed the hungry. “[He] introduces this fillet into New York high-end markets where you could sell fish for thirty or forty dollars a pound. There’s no argument that you could make that this is a food security item.”¹¹⁶ Despite the paucity of scientific data, in 2009 certification was granted. Recently, MSC also awarded its label to the highly controversial Antarctic krill fishery, which has been accused of robbing the sea of a resource critical to polar communities of seals, penguins, and great whales.

More broadly, Jacquet argues that “the incentives of the market have led the MSC certification scheme away from its original goal, toward promoting the certification of ever-larger, capital-intensive operations. Small fisheries that use highly selective, low-impact techniques, such as hook-and-line fishing or hand picking, are often sustainable, but make up only a tiny fraction of MSC-certified fisheries.” Given that around half of all fishes landed worldwide are caught by small-scale fishers, who lack the resources needed to apply for certification, the process effectively shuts the door on a giant fraction of the global catch. Brian Perkins openly admits, “it’s one of the things that we’re struggling with as an organization … to try to figure out how can we adapt to better serve the small-scale fisheries.”¹¹⁷ In the past few years improvements have been made, and fisheries in the developing world now comprise about 7 percent of certified stocks.¹¹⁸ Policy experts have suggested that small-scale fishers could achieve certification more readily by sharing expensive assessment costs between different fisheries targeting the same species, certifying multi-species fisheries as a single unit, and by promoting domestic support so certified fishes can also be sold locally.¹¹⁹

Another objection leveled at the MSC is that the certification process does not always lead to healthier fish stocks. An independent analysis of MSC-certified stocks in the northeast Atlantic found more than half of them still were “exploited above the maximum sustainable level” in their first year of certification.¹²⁰ An earlier review had found just 31 percent of globally certified stocks were overfished.¹²¹ Lead author Rainer Froese, of Germany’s Helmholtz Centre for Ocean Research, underscored that countries need not rely solely on the MSC and can independently ban sales of overexploited fishes. Certainly customers can also consult other seafood sustainability rating programs, such as those led by the World Wide Fund for Nature, the Marine Conservation Society, and Seafood Watch. And it would be unfair to place the burden of rescuing all declining fishery stocks, a planetwide problem, on the shoulders of any one of these organizations. Froese emphasized that certified stocks, despite their problems, remain a better option for the consumer: “it is still reasonable to buy certified seafood because the percentage of moderately exploited, healthy stocks is three to four times higher in certified than in noncertified seafood.”¹²²

In spite of all the challenges to comprehensively assessing a fishery, the MSC courageously waded into a shadowy labyrinth of mislabeled fishes and misleading claims and is trying to shed a little light. Certainly not all MSC certified fisheries are perfectly sustainable. But there are success stories. Alaska pollock (Gadus chalcogrammus) is fished throughout the Bering Sea and constitutes the second-largest fishery in the world. The Gulf of Alaska and Aleutian Islands fleet was awarded MSC certification in 2005 and recertified several times since. Worldwide catches had fallen from a peak of 9 million tons per year in the 1990s but stabilized by 2002 and have sustainably yielded some 5 million tons every year since.¹²³ The fishery, one of the first to be managed with transferrable catch shares, accounts for some 30,000 jobs in the United States alone. Sold in fish sticks, fast food, and countless other products, more often than not pollock is the first seafood a person tries as a child. Employing midwater trawls—nets pulled below the surface, but high above the bottom—the fishery boasts a laudably low bycatch rate estimated by NOAA Fisheries at less than 1 percent.¹²⁴ Because there are no agricultural inputs, pollock fishing also has an enviably small carbon footprint, on par with tofu; meanwhile, beef’s carbon hoofprint is a hundred times larger.¹²⁵ Alaska pollock seems to be just the kind of fishery that deserves to be certified by organizations like the Marine Stewardship Council, and purchased by consumers intent on supporting sustainability, employment, and the environment.

Invisible, Extraordinary, Indispensable

When you finally see what goes on underwater, you realize that you’ve been missing the whole point of the ocean. Staying on the surface all the time is like going to the circus and staring at the outside of the tent.

—Dave Barry, Miami Herald

While the oceans may seem invisible beneath the waves, many of our deeds on land are felt all too keenly by the sea. Diadromous and coastal fishes, whose habitats are directly connected to continents, are particularly at risk. Although the sight of oil spills on the ocean is heart-wrenching, as is the harm done when petroleum smears bird rookeries and sea otters, their direct impact pales in comparison to the indirect effects of runoff from land. The Mississippi River alone drains nearly half the continental United States, delivering a brew of silt, fertilizers, pesticides, and industrial chemicals into the Gulf of Mexico. Algal blooms are one inevitable result of too much runoff, and their decay can lead to anoxic dead zones, particularly when overfishing has decimated seafloor scavengers who would otherwise digest the excess algae instead of leaving it to rot. Tarpon and menhaden and bonefish are affected by runoff plumes and dead zones, as are Gulf shrimp and the fishers who toil to deliver them to our tables. Shoreline development and the elimination of key breeding habitats like salt marshes and mangroves, whether for high-rise hotels or aquaculture ponds, is kneecapping the ability of many nearshore fishes to reproduce. Inland factories, even backyard fire pits, release trace amounts of persistent organic pollutants like dioxins and PCBs that can be concentrated in the bodies of large and predatory fishes, affecting their wellbeing and ours.¹²⁶ The choices we make in our green third of the planet increasingly impact fish health in the blue two-thirds.

Far out in the Indian Ocean, more than a thousand miles from land, the Chagos Islands offer an illuminating, and encouraging, tale of the connections between land and sea. Many islands in the archipelago were invaded by rats that scuttled from seafaring boats while docked or beached. Rats are notoriously malign for seabirds, who have few defenses against terrestrial predators (the main reason they nest on remote islands). But not all islands in the archipelago were infested, and intensive removal programs have eradicated rats from several of the isles, setting in motion a natural experiment that reveals how readily we can restore the oceans through better land stewardship.

The differences between the rat-free and rat-infested islands could not be more stark. Where nest-raiding rats are present, seabird populations plummet. With them, a key source of nutrition vanishes: seabirds feed bountifully at sea, then defecate copiously on land, transporting marine nutrients to the islands. But as those nutrients disappear, a complex web of interactions begins to unravel. Trees and native vegetation decline by a factor of four, then nitrogen in soil and leaf litter fades.¹²⁷ Less natural nutrition reaches the sea, with nitrogen inputs falling nearly twentyfold, and nearshore algae are deprived of fertilizer. Algae crops suffer, and damselfish farmers decline in health and diminish in number. The abundance of zooplankton, which also depend on nitrogen inputs, sinks by two-thirds. When plankton is scarce, giant manta rays who normally feed near the islands are forced to quit the coastlines in search of richer pastures: manta sightings near affected islands tumbled from one every 14 minutes to precisely zero.¹²⁸

On islands where rats are absent, however, studies by Nicholas Graham from the UK’s Lancaster University revealed an ecosystem that was vastly healthier. Seabirds were 750 times more abundant, and soil nitrogen was 250 times higher than on rat-infested islands.¹²⁹ Damselfish and other fishes, thanks to more luxurious algal pastures, grew faster and saw their combined biomass increase by almost 50 percent. Algae grazing rates, a key determinant of coral recovery, were also boosted, improving the reef’s ability to withstand storms and climate change. Dr. Graham fingered the culprit and underscored what we can do to support the sea: “rat removal should be a conservation priority for coral reef islands. The return of seabirds would benefit not only the island, but also adjacent nearshore marine ecosystems.” Protecting damselfish, seabirds, coral reefs, and manta rays is well within our grasp, but it is a job that starts on land.

Meanwhile, out at sea, a future of stable fish populations and sustainable seafood is now visible on the horizon. Many of the solutions have been identified already and are supported by years of scientific evidence. What remains is the heavy lift of achieving publicly acceptable remedies, ones that policy makers and fishers and consumers alike can embrace. Our planet is not going to stop eating salmon, cod, snapper, and tuna. Fisheries already harvest food from an area four times larger than terrestrial agriculture.¹³⁰ But the world can reduce overfishing by shrinking catch quotas, modifying gear, and limiting subsidies that prop up today’s overcrowded fishing fleets. Despite some resistance from fisheries, it is clear that healthy and well-managed seafood stocks will actually be more, not less, productive in the long term. Some estimates suggest that if all the world’s fisheries were managed properly, the rebuilt stocks would yield an astonishing 18 million tons more seafood than we are producing right now.¹³¹ As it is, more than 80 percent of all seafood landings today come from stable stocks, including two-thirds of the ten most landed species, so the dream of sustainability is within reach.

Much of the work of repairing fisheries will need to be done by governments. Daniel Pauly, 2023 co-recipient of the distinguished Tyler Prize for Environmental Achievement (with fisheries economist Rashid Sumaila), lays the responsibility for saving the fishing industry from itself directly at the doorstep of the world’s legislative bodies. “Governments are the only entities that can prevent the end of fish. For one thing, once freed from their allegiance to the fishing-industrial complex, they are the ones with the research infrastructure capable of prudently managing fisheries. For another, it is they who provide billions of dollars in annual subsidies that allow fisheries to persist despite the lousy economics of the industry.”¹³² The sea can bounce back from overfishing, and will, but only after fisheries are compelled to slacken their grip on the sea. Rashid Sumaila coined the term “infinity fish” to describe what the oceans could then provide: “If we manage them well, if we use them wisely—they can continue to deliver fish to us for food, for income, for jobs—forever.”¹³³

Individual people can also contribute much to sustaining wild fish populations, today and into the future. Adopting a vegetarian diet is a healthy option and immediately alleviates pressure on wild fishes. Those who do choose to eat seafood can carefully select which species and fisheries they support. Households can become better informed and purchase fish from well-managed fisheries, following guidelines from auditors like the Marine Stewardship Council and Seafood Watch. These organizations should be pressed, like all organizations, to improve their methods, their accuracy, and their equity. But such votes by pocketbook nourish those fishers who are sustaining their stocks, while starving unlicensed and unregulated operators who decimate theirs. Catch-share systems can be improved, so artisanal fishers are treated fairly, and so quotas are no longer concentrated in too few hands. Government agencies can require fisheries and distributors to faithfully record the chain of custody of every fish caught in the sea. Novel approaches, like the block-chain system piloted in Mauritius, show new technologies can provide that traceability from net to plate. Consumers can patronize fish farming and ranching while at the same time urging the reduction of wild-capture fish meal, the adoption of creative new feed stocks, and a stronger emphasis on farming nonpredatory species. These improvements can alleviate the strain on wild fish populations and supply people with healthy seafood, a source of protein better in many ways for the planet than terrestrial livestock.

And no matter what you eat, you can enjoy blue tourism, visiting some of the majestic and awe-inspiring sites the sea has to offer. Snorkeling and scuba diving offer a ticket to the world beneath the waves, making visible what was formerly invisible; so do glass-bottom boat tours, sea kayaking, paddle boarding, and trips to an aquarium. Blue tourism provides invaluable support for marine protected areas and sustains the local economies that surround and depend on them. Sharing the rapture of swimming with whale sharks, snorkeling over coral reefs, or watching fishes behind glass will foster that delight in others, from naturalist guides to government ministers, and even school groups you might bump into at the aquarium.

By assembling a stained-glass window of these myriad solutions, we can complete our evolution from hunter-gatherers, who hauled wild animals from the sea, to farmers and ranchers who responsibly cultivate food for a hungry planet. The oceans are magnificently resilient, they have rebounded many times before, and they will recover again when given a chance. Above all, we must understand and respect the nature of fishes, lest we ask of them more than they can give and test them more than they can bear. Our vast blue seas, which harbor some of the most extraordinary and indispensable animals on Earth, deserve nothing less.