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Striped marlin fishing: the marlin that lights up its stripes when it hunts

The striped marlin wears its name on its flanks: around a dozen to twenty vertical blue stripes run down its sides, and according to the English Wikipedia they remain visible even after death. While it is alive, they do more than that. Special pigment cells, the chromatophores, contract or expand, and when the fish is excited the stripes turn from bluish to lavender. This article is about the striped marlin, *Kajikia audax* — in German Gestreifter Marlin, in Spanish marlín rayado, in Italian marlin striato, in French marlin rayé, in Portuguese espadim-raiado, in Finnish raitamarliini, in Russian полосатый марлин, in Japanese マカジキ (makajiki).

The Pacific sister of the white marlin

The striped marlin belongs to the billfishes (Istiophoridae), like the blue marlin, the white marlin, the sailfish and the Mediterranean spearfish, to each of which this series devotes a group of its own. Its closest relative is the white marlin of the Atlantic: in 2006, after genetic studies, American scientists placed both in the new genus *Kajikia* (Russian Wikipedia); before that, the striped marlin stood in the genus *Tetrapturus*, and according to the Japanese Wikipedia much of the literature still uses that name. It was first described in 1887 by Rudolph Amandus Philippi, from a fish caught off Iquique in Chile. Its species name comes, according to the Russian Wikipedia, from Latin *audax*, bold — why, the author did not explain; perhaps because of the bold stripe pattern.

According to FishBase it is a pelagic, oceanic fish that lives between the surface and 200 m, usually above the thermocline, and it prefers cooler water than the black and the blue marlin. FishBase calls it the most widely distributed billfish; the German Wikipedia, the most common of the marlins. Its abundance increases with distance from the shelf; it comes close to the coast only where the bottom drops off steeply (German, Italian, Finnish Wikipedias). It is mostly solitary; in the spawning season it forms small schools of fish of similar size (FishBase, Italian Wikipedia).

Its prey: fish, squid and crustaceans (FishBase). The English Wikipedia names sardines, mackerel, small tunas and squid, above all the jumbo squid; a study off Mexico found that it preferred schooling fish such as the chub mackerel and the Pacific sardine. The Japanese Wikipedia adds flying fish and horse mackerel. According to the Japanese Wikipedia it swims with the upper half of its tail fin out of the water and sometimes leaps clear of the surface; it reaches 80 km/h.

How to recognise it

An elongated, laterally compressed body with a long, round, spear-like bill (FishBase, Italian and Russian Wikipedias). The surest feature is the first dorsal fin: at the front it rises into a high, pointed lobe that is as tall as or taller than the body is deep (FishBase, English, Russian and Japanese Wikipedias). FishBase gives the first dorsal fin 42 to 48 soft rays, the anal fin 18 to 24, the pectoral fins 18 to 22. The pectoral fins are long and narrow and, according to the Russian Wikipedia, lie close against the body. The back is dark blue, the belly silvery white; the first dorsal fin is blue-black without dark spots (FishBase). And then the stripes — how many, and what colour, the sources tell differently (see below).

According to the Japanese Wikipedia it resembles the blue marlin, but its first dorsal fin is taller than its body, its scales are finer, its body is paler and flatter and its bill is longer. Its sister, the white marlin, lives in the Atlantic; according to the German Wikipedia the striped marlin’s dorsal fin is higher than its body and without black spots.

  • Size: FishBase gives 420 cm total length as the maximum, 290 cm as the common length and 440 kg as the heaviest published weight. According to the Russian Wikipedia the largest fish recognised by the IGFA weighed 224.1 kg, caught off New Zealand on 16 January 1986.
  • Age and maturity: FishBase gives 9 years as the maximum reported age, the English Wikipedia up to 10 years. FishBase gives 210 cm as the length at first maturity.
  • Spawning: Females are batch spawners (FishBase). According to the English Wikipedia a female spawns 4 to 41 times in one season, with up to 120 million eggs; according to the Russian Wikipedia, off Taiwan, every 3 to 7 days.

Where it lives — and why not in the Mediterranean

FishBase: in tropical, subtropical and temperate waters of the Indo-Pacific, between 46° North and 49° South. In the Pacific its range forms a horseshoe, open towards Central America (FishBase, German and Russian Wikipedias); according to the German Wikipedia it runs from Japan via Ecuador and Peru to Australia, touches the north coast of New Zealand and is common around Hawaii. In the Indian Ocean it is densest off East Africa, in the western Arabian Sea, in the Bay of Bengal and off north-western Australia (FishBase, German Wikipedia). In Japanese waters, according to the Japanese Wikipedia, it occurs south of Hokkaido, more often on the Pacific side than in the Sea of Japan.

In the Mediterranean it is not found: none of the sources lists it there. Its Atlantic sister, the white marlin, is the one that turns up in the Mediterranean — rarely, and, according to FishBase, mostly as single strays. For an angler from Europe this means: the striped marlin is a travel fish. Where it is caught, the sources describe from the commercial side: with longlines (according to the Italian Wikipedia mostly as bycatch of tuna longlines), by trolling, with handlines and harpoons (Russian, Japanese Wikipedias); Japan and Taiwan land the most (Italian, Russian Wikipedias). According to the German Wikipedia sport anglers are encouraged to release fish that are not trophy-sized.

On the plate — and the mercury

In Japan, according to the Japanese Wikipedia, the striped marlin is the highest-grade of all billfishes; its red flesh is eaten as sashimi and sushi, and FishBase and the Italian Wikipedia call it the best of all marlins for that. FishBase puts it in the price category very high. But the Japanese Wikipedia also warns of the mercury in its flesh: in 2005 the Japanese Ministry of Health listed it among the fish whose intake pregnant women should watch, with a guideline of twice a week at about 80 g a portion. The German Wikipedia writes that the mercury content is pointed out deliberately, to dampen demand.

Eight contradictions, left standing

  • How big does it get? FishBase and the French, Italian and Russian Wikipedias: up to 420 cm and 440 kg. The German: 4.4 m and 420 kg (females; males stay smaller). The Finnish: 4 m. The English: 4.2 m, but only 220 kg — close to the 224.1 kg that the Russian Wikipedia gives as the IGFA record.
  • How many stripes? The English Wikipedia: 12 to 20. The German: usually 18 to 22. The Italian: up to 15. The Russian: 15 to 20 rows, each made of round dots or narrow stripes. FishBase itself gives both: about 20 and about 15 rows. The Japanese: a dozen or more.
  • What colour are the stripes? The English Wikipedia: bluish, turning lavender when it is excited. The German: light blue, paler or fainter with its mood. The Russian: cobalt. The Japanese: light blue. The Finnish: light green.
  • How deep does it swim? FishBase and the German Wikipedia: 0 to 200 m. The Finnish: usually less than 100 m. The French: usually 0 to 5 m, rarely deeper than 100 m. The English Wikipedia says it hunts by day in the top 100 m, often near the surface — and in the same article cites a study in which it stayed deeper by day and gathered near the surface at night.
  • When is it mature? The English Wikipedia: males at 1 to 2, females at 1.5 to 2.5 years. The French: at 2 to 4 years. The Russian: females off Taiwan at 4 to 8 years. And the maximum age: 9 years (FishBase) or 10 years (English Wikipedia).
  • How warm does it like it? FishBase: 20 to 25 °C. The German Wikipedia: 20 to 26 °C. The English: its largest populations at 20 to 28 °C surface temperature. For spawning, the Italian gives at least 25 °C, FishBase a lower limit of about 24 °C for the larvae, the Russian a spawning peak at 24.8 to 28.3 °C.
  • Is it threatened? FishBase and the Italian Wikipedia: Least Concern on the IUCN Red List. The Finnish and Swedish Wikipedias: Near Threatened. The German: in the USA it was declared a threatened species in 2008; around 2005 the catch was well below what the species could bear. The Italian: stocks fell by 20 to 25 % in 16 years. The English: in 2010 Greenpeace put it on its red seafood list.
  • Does it reach the Atlantic? FishBase and the German Wikipedia: Indo-Pacific; according to the German, contact with the white marlin off the Cape of Good Hope is too slight to stop the two species evolving apart. The Italian and the Russian: rare strays on the Atlantic side of South Africa, the Russian also off West Africa — they do not spawn there. The Finnish: sometimes in the Atlantic. The opening line of the Russian Wikipedia simply counts the Atlantic among its oceans.

Five names that lead to the wrong fish

  • “Spearfish”, “spjutfisk”, “копьеносец”. GBIF also lists it in English as high-finned spearfish, the Swedish Wikipedia calls it strimmig spjutfisk, the Russian полосатый копьеносец — each literally a spearfish. But spearfishes in the narrower sense are the genus *Tetrapturus*, in which the striped marlin stood until 2006 — among them the Mediterranean spearfish, to which this series devotes a group of its own.
  • “Pez espada” and “pez vela”. GBIF also lists both, without a language. But pez espada is the Spanish for the swordfish, and pez vela for the sailfish — two other billfishes, to each of which this series devotes a group of its own.
  • “Aguja”, “agujón”. GBIF also lists it in Spanish as pez aguja and agujón. But in Spanish aguja also stands for the garfish, to which this series devotes a group of its own — a fish of barely a metre, with no relation to the marlins.
  • “Empereur”. GBIF also lists it in French as empereur and empéreux. But the sailfish, too, is called empereur éventail in French — the same “emperor” for two different billfishes.
  • “マカジキ” and “メカジキ”. In Japanese, マカジキ (makajiki, “true marlin”) is the striped marlin, メカジキ (mekajiki) the swordfish: one character apart. And the white marlin, its sister, is called ニシマカジキ (nishi-makajiki, “western makajiki”) according to the Japanese Wikipedia.

That leaves the question every article in this series starts with: when. Habitat, prey and habits are above, and they are fixed. What changes every day is everything else — and whether a day on the water is worth it is decided right there. That is what StrikeAhead works out: it takes the conditions on your water and tells you when the trip is worth it. And because nobody reads drop-offs, bait schools and the blue of the open sea from day one, StrikeAhead Pathfinder tells you who to go out with: curated guides and skippers, personally checked before listing — licence and insurance —, with verified catches instead of promo photos, no paid ranking, and for you as an angler no booking fee.

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