Bullet Tuna Fishing: The Smallest Tuna, Whose Name Means “To Grow”
Every article in this series answers the same question: how does the angler outwit the predator? With which bait, at what depth, at what time. With the bullet tuna, the answer begins with a contradiction in the name. Its genus is called *Auxis* — and by the most likely reading the word goes back to the Greek *auxo*: to grow. Yet it is one of the smallest tunas of all, usually around 35 centimetres in the catch. So the pole of this article is: the smallest tuna, whose name means “to grow”. The fish is *Auxis rochei*, the bullet tuna — melva in Spain, tombarello in Italy.
An ancient name for young tunny
The origins of scientific names are recorded by the ETYFish Project, an etymological register of fish names. There, the genus Auxis (Cuvier 1829) is an “ancient name for scombrid fishes”, “sometimes used to designate a young tunny”, “perhaps derived from auxo, grow”. ⚠️ The “perhaps” is in the source, and this article keeps it: the link to “grow” is a suggestion, not a finding. According to ETYFish, the species name rochei (Risso 1810) honours the Swiss physician and naturalist François-Étienne Delaroche (1780–1813), whose papers on Mediterranean fishes Risso cites several times. The Mediterranean subspecies is *Auxis rochei rochei*; a second one, *eudorax*, is named for its well-developed armour of scales behind the head, the so-called corselet.
What people call it is shown by the GBIF list for *Auxis rochei* (key 4286088, 188 entries). There is a frigate camp: German “Fregattmakrele”, English “frigate mackerel”, Danish “fregatmakrel”, Dutch “fregatmakreel”, Russian “макрель-фрегат”, Arabic “ماكريل الفرقاطة”. A bullet camp: English “bullet tuna”, Finnish “kuulamakrilli”, Dutch “kogeltonijn”, Arabic “تونة الرصاصة” — the tuna shaped like a projectile. A melva camp in the west: Spanish “melva” and “melvera”, Catalan “melva”, Portuguese “judeu melveira”. A tombarello camp in the centre and east: Italian “tombarello”, Maltese “Tumbarello” and “Tumbreall”, Turkish “gobene balığı” and, according to ICCAT, “tombik balığı”, Greek, according to the ICCAT manual, “Τουμπαρέλι” next to “Κοπάνι”. And a few languages simply take the genus: Swedish and Norwegian “auxid”, French “auxide” next to “bonitou”.
💣 Three name traps, each checked at the source. First, “frigate”. GBIF gives the same names to the sister species *Auxis thazard* (key 4286082), usually called “frigate tuna” in English — and conversely, “Frigate Tuna” also appears in the *A. rochei* list. The manual of ICCAT, the International Commission for the Conservation of Atlantic Tunas, writes that some authors treated both as a single species, that they often swim in the same school, and that unknown quantities of bullet tuna in landings are recorded as frigate tuna. Second, “bonito”. The GBIF list for *A. rochei* includes English “Bonito” and “Plain Bonito”, Spanish “Bonito”, French “bonite”, Arabic “بونيتو العادي” and German “Unechter Bonito” — but the bonito is *Sarda sarda*, and the “false bonito” is *Euthynnus alletteratus*, the little tunny; both have their own articles in this series. Third, “trup”. Croatia’s recreational sea-fishing regulation (NN 48/2026, Annex 1) lists “trup Auxis rochei” — yet in Albanian, “Trup” is, according to ICCAT and EUNIS, the little tunny, and the Slovenian “Trupec” is, according to ICCAT, the bullet tuna again. One word, three coasts, two fish.
Small, fast, without a swim bladder
The key facts, each with its source. The ICCAT manual (chapter 2.1.10.2, updated 30 June 2021) calls it “one of the smallest members of the Scombridae family”, the mackerel and tuna family. In the eastern Atlantic up to 51 centimetres fork length, in the Strait of Gibraltar up to 47 centimetres and about 1.9 kilograms; the common size is 35 centimetres. According to ICCAT it matures at 34 to 36.5 centimetres — roughly the size at which it is usually caught. FishBase gives a maximum of 50 centimetres and a maximum age of 5 years; IUCN status “Least Concern”, assessed on 1 March 2022. A name that means “grow” and a fish that barely does: that is the pole.
Two traits from the ICCAT manual explain its behaviour. “Swim bladder absent” — it has no swim bladder and must keep swimming so as not to sink. And it forms “large schools of similarly sized individuals”. In appearance: an iridescent blue back turning deep purple to almost black on the head, 15 or more dark, oblique to nearly vertical wavy lines above the lateral line, a white belly without stripes, two widely separated dorsal fins and a broad corselet.
When and where it holds in the Mediterranean
According to ICCAT it is epipelagic and neritic — living in the upper water layer and over the continental shelf — with a seasonal coastal distribution in the Mediterranean. It is more abundant in the Strait of Gibraltar, along the North African coast and on the Spanish Mediterranean coast; according to the studies cited there, most *Auxis* caught in the Mediterranean may be *A. rochei*. A migration is described from the Atlantic through Gibraltar to the Balearic Islands and back out — “close to the shore”. According to ICCAT, spawning in the Mediterranean runs from June to September, in the Aegean from March to September according to Bök and Oray (2001). On the Algarve coast it is caught between May and November, linked to warmer water with the Levante wind. ⚠️ These are observations from studies, not a calendar for your bay.
What it eats — and what eats it
The ICCAT manual states: “Food is primarily selected by the size of gill rakers.” It eats fish, crustaceans and cephalopods; among fish mainly small pelagic fishes, particularly anchovies and other clupeoids, among crustaceans mainly larval stages (megalops and stomatopod larvae). FishBase adds squid. At the same time it is prey itself: ICCAT lists several tuna species, pelagic sharks, billfish and large pelagic fish such as dolphinfish (*Coryphaena hippurus*) and barracuda (*Sphyraena*) as its predators. It is considered “forage prey” — food for the big ones.
What that means on the water
- Think small. A predator that eats anchovies and crab larvae, and whose food is selected by its gill rakers, is not a case for big lures. As with the little tunny: size often beats action. None of the sources read here say exactly which lure size catches; this article promises none.
- One fish shows the school. Because it gathers in schools of similar size, the first fish tells you how big the others are — and whether your lure matches the fish that are there right now.
- It never stands still. Without a swim bladder, it has to swim. A school that was boiling on the surface a moment ago can be gone seconds later — quick casts beat long pauses.
- The season is the coast. The sources describe a seasonal coastal distribution, Mediterranean spawning from June to September and a migration close to the shore. When it is off your shore is not something a manual can tell you — the water can, and so can your catch log.
- Where it hunts, the big ones hunt. Dolphinfish, barracuda and tuna eat bullet tuna. A school on the surface can therefore also be the sign of a bigger fish below.
- You will hardly identify it with certainty. *A. rochei* and *A. thazard* often swim together and, according to ICCAT, look very alike; one difference is the width of the corselet below the second dorsal fin (in *rochei* more than 6, usually 10 to 15 scales). This article is not an identification key.
- Check the rules yourself. EU Regulation 2019/1241 (Annex IX, minimum sizes in the Mediterranean) lists no *Auxis* species; Croatia’s regulation NN 48/2026 lists “trup Auxis rochei” among species with a catch-record duty. Rules differ by country and change — the responsible authority is what counts; this is not legal advice.
The bullet tuna is the tuna that does not follow its name: it is supposed to mean “grow” and stays one of the smallest in its family, it shares its frigate name with its sister and its Croatian word with the Albanian little tunny. StrikeAhead reads conditions and depth and learns from your catches; the app tells you when it is worth it, and StrikeAhead Pathfinder tells you who to head out with on unfamiliar water — curated, personally vetted, with verified catches instead of promo photos.