Excerpted from Kings of Their Own Ocean: Tuna, Obsession, and the Future of Our Seas by Karen Pinchin with permission from Dutton, an imprint of the Penguin Publishing Group, a division of Penguin Random House, LLC. Copyright © 2023 by Karen Pinchin.

More than 30,000 years ago, the Strait of Gibraltar was a broad plain. Lapping several kilometers from the limestone cliffs that now tower above its blue, continent‑splitting waters, sea levels were roughly 120 meters lower than those in modern times, a height difference about the size of the Great Pyramid of Giza. In spring, as they had for thousands of years before the earliest hominid evolved, bluefin tuna migrated from the cold, deep Atlantic inward toward the Mediterranean, drawn by instinct and ancient memories of spawning in the in‑land ocean’s shallower, warmer currents. At the time, the African and European continents were a mere 10 kilometers apart, separated by two distinct, deep channels that had not yet merged, and wouldn’t for thousands of years.

Throughout the fall and winter, huge schools of millions of bluefin prowled the chilly Atlantic Ocean, feasting on its bounty of fatty mackerel and herring, building fat stores and millions of eggs and spermatozoa that would help them complete their annual cycle. These ancient ancestors navigated using a combination of light, scent, and possibly electromagnetism. Each had a translucent pinhole atop its forehead, called a pineal window, which channeled light down a cartilaginous stalk to the pineal organ. That organ allowed each fish to sense light, possibly even beams from the moon and stars. Just before dawn and just after dusk, the fish plunged away from the ocean’s surface to recalibrate their internal compasses. By sensing light during the day and tracking the sun’s progress around the earth, they followed cosmic patterns that accompanied their ancestors and would guide their children. They oriented themselves in relation to polarized light in the water, and used shifts in temperature, salinity, and the directions of the currents they swam with and against to find their way. Some of their bones contained trace amounts of the iron‑ based mineral magnetite, hardly surprising on a planet beset with electromagnetic waves—waves that could provide clues on where the tuna were and where they were heading.

Heading eastward, the outflowing ocean current was strong, but so were they. In the open ocean they were kings, but in the narrowing bottleneck of the strait they were suddenly transformed into prey themselves, now pursued by pods of canny orca whales. It was a race some of them couldn’t win, their fast, stiff bodies darting and cornered, diving and leaping out of the water. At least they had their speed. That speed was their defense, but could also be their downfall. Blinded by an instinct to escape, some fish rocketed onto the shallow beaches and shoals, where, as they had for countless seasons, small groups of Neanderthals waited, arms outstretched, for a gift from the sea.

Starting in 1989, the Gibraltar Museum supervised excavations of Gorham’s Cave, part of a network of tunnels and chambers unearthed by colonial British engineers between 1782 and 1968, about an hour’s drive from Cádiz, Spain. In 1907, Captain A. Gorham explored the high‑ceilinged cave that would later bear his name. Tucking themselves into the Paleolithic caves, the modern researchers unearthed a trove of evidence of the Neanderthals who once sheltered there, covered by layers of sand gradually blown, grain by grain, into the cave by harsh easterly winds, drawn toward fires vented through the cave’s 80‑meter chimney. “Gorham’s Cave is a time machine,” evolutionary biologist Clive Finlayson told tuna writer and researcher Steven Adolf in his book Tuna Wars.

Throughout the 1990s, while exploring Gorham’s Cave and other neighboring caves within a 28‑hectare complex spanning the main ridge, researchers from around the world found charcoal, bone fragments, charred pine seeds, and what seemed to be blade fragments. They also found what they identified as “macro‑ichthyofauna identifiable by tuna vertebrae of medium and large size”—or, in other words, evidence that both medium and large bluefin had been eaten within the caves. Paired with later‑found evidence of fires and of tuna beachings caused by orca attacks in shallow waters, it signaled that even as the earliest modern humans spread across the globe, at least one hominid species already had figured out how to catch and consume tuna.

One of the researchers working in the field was a young professor at the Autonomous University of Madrid named Arturo Morales‑Muñiz. In the mid‑1990s Morales‑Muñiz was widely referred to by Madrid’s fishmongers as “the bone man.” He visited their central fish market, Mercamadrid, every few weeks searching for the carcasses and bodies of their strangest creatures. Sometimes he’d buy a whole fish or a bagful, paying with coins he pulled from a battered leather change purse. Other times the fish were too large, like tuna or swordfish, so he’d settle for stripped, bloody skeletons. He loaded them into his trunk in leakproof containers scavenged from the market’s garbage piles. His car stank, he knew, but it helped that he was “almost like a whale,” he said, in that he had very little sense of smell.

Kings their Own book cover with black and orange text and bluefin tuna illustrations
Courtesy of Dutton

In April 2022, I joined the tall, amiable Morales‑Muñiz on a predawn visit to Mercamadrid, home of the second‑largest fish market in the world after Tokyo’s. Since 1982, cars have flowed past its entrance hours before the sun rises. Within its cavernous fish warehouse, thousands of people working for more than 100 companies operate forklifts, butcher fish, and sort a dazzling array of marine creatures by weight and size, quality, and when they’ll spoil. Its aisles are closely packed with boxes of fish, cooler booths, and walk‑in refrigerators with offices above.

Seven days a week, the market echoes with the shouts of fish‑mongers, some clad in blood‑and-ichor‑stained aprons and ranging on a temperamental scale from furious to jolly. They’re closely flanked and constantly approached by insistent salesmen, competitors gathering intel, and cooks in chefs’ jackets looking for the day’s fish specials. The day I visited, the sellers of fish were only men—men with beards and mustaches, bald men, old men, young men—who used whetstone‑sharpened machetes, cleavers, and fine boning knives to separate bluefin flesh from bone and portion steaks. Their short, blunt fingernails scraped against the shells of shrimp and mussels as they weighed fish, shellfish, and a dizzying array of marine creatures on metal scales by the handful, the bucketful, the crateful.

Back in the early years, as Morales‑Muñiz pursued his mission to gather as many animal skeletons as he could, he often found himself in bizarre and sometimes dangerous situations. What he was doing seemed insane, he knew, scavenging carcasses of “strange beasts” from the side of the road and harassing fishmongers for their strangest, most far‑fetched and ‑flung fish. But it drove him crazy, how his country’s archeologists seemed to worship only the relics and old walls left behind by the Romans and ancient Phoenicians, ignoring any bone that wasn’t human. But if bluefin had indeed been the mortar of conquest and early Mediterranean civilizations, why hadn’t his colleagues yet identified the fish’s huge, arcing bones anywhere in the fossil record? For decades, historians and archeologists had insisted that the fish’s calorie‑rich body had fueled armies and provided early Europe with garum, a fish sauce that was one of its most expensive products. But if that was the case, why wasn’t evidence of the fish being found on dig sites?

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