Mackerel

• 1. Introduction

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  Mackerel are found in both temperate and tropical seas, and in 2009 alone, commercial fishermen hauled in over 5 million tons of them. That number makes mackerel one of the most intensively caught fish on earth. Yet for much of the 20th century in Britain, less than 10 percent of housewives surveyed had ever bought one. The same fish feeding whales off the coast of Madagascar, outrunning sharks with burst speeds that rival a highway car, had spent decades sitting invisible in the fishmonger's display case. How did a creature so central to ocean life become so overlooked on the dinner table? And what does a name derived from Old French, possibly meaning either "spotted" or "pimp", tell us about how people have related to these fish for centuries? Those are the threads this documentary will follow.

• 2. What Makes a Mackerel

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  Scomber scombrus, the Atlantic mackerel, is the type species for scombroid mackerels. Its iridescent blue-green back and near-vertical wavy black stripes make it one of the most recognizable fish in the North Atlantic. Those stripes have puzzled scientists, because mackerel live in open midwater environments with no background to hide against. The explanation that emerged is more elegant than simple camouflage. Fish have an optokinetic reflex sensitive to moving stripes, and the markings on a neighbouring fish serve as "schooling marks" that help each individual align itself and match speed with its companions.

  In 1998, E J Denton and D M Rowe proposed an additional function for a layer of thin, reflecting platelets visible on some of the stripes. As a fish's orientation shifts relative to a neighbour, the amount of light those platelets reflect also changes. Denton and Rowe argued this gives mackerel considerable advantages in reacting quickly while schooling and feeding. The lateral line system reinforces this coordination further.

  Beyond their markings, mackerel carry the hallmarks of their Scombridae family: scales so small they are nearly absent, fins that retract into grooves for streamlining, and no swim bladder. Atlantic mackerel can sustain a swimming speed of 0.98 metres per second and burst to 5.5 metres per second. The Wahoo, Acanthocybium solandri, reaches speeds of up to 78 kilometres per hour, placing it among the fastest fish alive. In the Latin family, the fish earned the nickname "punctualis piscis" for their reliable punctuality during migration season.

• 3. A Family of Thirty

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  Over 30 species carry the mackerel name, and that number conceals surprising variety. The tribe Scombrini, the true mackerels, contains just seven species split between the genera Scomber and Rastrelliger. The Atlantic chub mackerel and the Indo-Pacific chub mackerel were long treated as a single species. In 1999, Collette demonstrated through molecular and morphological analysis that they are in fact separate, a distinction that took decades of scrutiny to settle.

  The Spanish mackerels, tribe Scomberomorini, add 21 more species. The largest is the Chinese mackerel, Scomberomorus sinensis, which can reach 247 centimetres and 131 kilograms. The wahoo, classified within this tribe, lives in all oceans between 59 degrees North and 48 degrees South. The narrow-barred Spanish mackerel, Scomberomorus commerson, can stretch to 240 centimetres and is listed as near threatened on conservation assessments.

  Beyond the Scombridae, families including Carangidae and Gempylidae contribute further species to the mackerel roster, among them the Chilean jack mackerel and various snake mackerels. The blacksail snake mackerel, Thyrsitoides marleyi, can reach 200 centimetres. By extension, the mackerel name has also attached itself to cloud formations, a tabby cat pattern, and a variety of other fish from the mackerel shark to the mackerel tuna. The word's reach across biology and culture reflects just how embedded this fish became in the observations of people living near the sea.

• 4. Migration and the Open Sea

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  Spinner sharks follow migrating schools of mackerel off the coast of Madagascar. Bryde's whales intercept those same schools using skimming, lunging, and bubble net techniques. Flocks of seabirds, dolphins, and large predatory fish such as tuna and marlin also converge, attacking mackerel schools in coordinated and cooperative ways. The mackerel sits at a critical juncture in the food web, serving as forage for nearly every large marine predator.

  The migration patterns themselves are intricate. Some coastal stocks move in large schools along the shore to shallow spawning grounds, then return in smaller groups to feeding areas near zones of upwelling. From there they may push offshore into deeper water and spend winter in relative inactivity. Other stocks cross entire oceans. The Wahoo disperses across all major ocean basins.

  Individual females broadcast between 300,000 and 1,500,000 eggs near the water's surface, because the eggs float. Larvae and juveniles drift in the open ocean and feed on zooplankton. Adult snake mackerel conduct a diel vertical migration, spending the day in deep water and rising to the surface at night to feed. Their young reverse this pattern, staying near the surface by day and descending at night. This layered use of the water column allows multiple life stages to occupy the same ocean without directly competing.

• 5. The Catch

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  Chub mackerel, Scomber japonicus, account for roughly half the total capture production of scombroid mackerels. Together with Atlantic mackerel, the two species represent about 75 percent of the entire scombroid mackerel catch. Fishermen most commonly target chub mackerel at night using surround nets, drawing them in with lampara lamps that attract the fish to the surface.

  The North Sea has been overfished to the point where ecological balance has been disrupted and jobs in the fishing industry have been lost. In the Southeast United States, overfishing of king and Spanish mackerel in the 1980s prompted a regulatory response covering size limits, fishing locations, and bag limits for both recreational and commercial fishers. Gillnets were banned in Florida waters. By 2001, stocks had recovered.

  Chilean jack mackerel, among the most heavily fished non-scombroid species, have been overfished to a degree that puts the fishery at risk of collapsing. Purse seining is the dominant method for schooling surface species: large vessels use spotter planes to locate schools, then close in with sonar to track the school's shape before encircling it with fast auxiliary boats deploying purse seines. Trollers work mackerel near the surface using long booms and electric or hydraulic reels, while fish aggregating devices are deployed to concentrate the catch. Sport fishermen pursue the king mackerel specifically for its fighting ability.

• 6. Stinking Fish and Silver Tables

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  The authors of The Cambridge Economic History of Europe observed that there are more references to stinking mackerel in English literature than to any other fish. That reputation was earned honestly. Mackerel flesh spoils rapidly, especially in tropical conditions, and can trigger scombroid food poisoning if not eaten on the day of capture or properly refrigerated. Before canning arrived in the 19th century, English consumers faced a narrow window for fresh mackerel and no practical means of preservation beyond salting or smoking. Historically, the English did not preserve mackerel at all, consuming it only fresh, which made spoilage routine.

  France took a different approach. Mackerel was traditionally pickled in large amounts of salt, which allowed it to move widely across the country as a preserved product. The divergence in national habits shaped how each culture related to the fish for centuries.

  In Britain, folklore compounded the practical problem. Mackerel were considered unclean in some circles because of beliefs that they fed on the corpses of drowned sailors. A 1976 survey of 1,931 housewives conducted by the White Fish Authority found that fewer than 10 percent had ever purchased mackerel, and only 3 percent bought it with any regularity. Many UK fishmongers during that decade did not display or even stock it. The fish's omega-3 content and its abundance in British waters were irrelevant to consumers anchored to cod, haddock, and salmon.

• 7. A Name With Strange Roots

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  The word "mackerel" comes from Old French and may originally have meant either "marked, spotted" or "pimp, procurer." Medieval ideas about animal procreation allowed both readings to coexist. Mackerel spawn enthusiastically in shoals near the coast, and that conspicuous fertility apparently invited the more provocative interpretation, even if the precise logic is not fully clear from surviving sources.

  That same etymological flexibility persists in how the name is used today. It modifies clouds in the form of the altocumulus mackerel sky formation. It labels a coat pattern in the mackerel tabby cat. It appears in the names of the mackerel shark, the shortfin mako, and the mackerel tuna, Euthynnus affinis, species that share visual characteristics with the scombroid family. Even the mackerel pike and the mackerel icefish, Champsocephalus gunnari, carry the designation despite belonging to entirely different families. The name has travelled so far from its biological roots that it now functions as a loose descriptor for stripes, speed, and sea-going habit, an informal shorthand built up over centuries of fishermen, cooks, and naturalists reaching for a familiar reference point.