Little Tunny: The Predator Your Lure Is Too Big For
There is a scene everyone knows who fishes the Mediterranean from a jetty or a small boat: the water boils. A hundred metres of surface breaks open, gulls drop in, baitfish fly. You cast straight into it — and nothing. Not one touch. Faster. Then slower. Then a different colour. And the sea keeps boiling without you. ⚠️ It is almost always the same fish, and almost always the same mistake. The fish is the little tunny, *Euthynnus alletteratus* (Rafinesque, 1810) — GBIF 5208565, family Scombridae, ICCAT species code LTA. And the mistake is not your speed. Your lure is too big. For forty-one articles this series has been about place, timing and retrieve. This predator asks the question that has never come up: how big is the mouthful?
The tuna that stands at your feet
First, why you get this close to a tuna at all. The ICCAT manual (chapter 2.1.10.5 LTA) separates it from every other tuna in this series in one sentence: “Atlantic little tuna is an epipelagic and neritic fish that typically occurs in inshore waters, being more coastal than other tuna species.” Bluefin needs authorisation, timing and a boat; albacore sits far out with no signs at all. This one is at the breakwater. ICCAT also says exactly where: “usually found in coastal waters with swift currents, near shoals, around the warmer waters of thermal fronts and upwellings” — coastal water with strong current, over shoals, on the warmer side of thermal fronts and upwellings; most abundant between 24 and 30 °C. It schools “according to size” and scatters at certain times of the year. In the Mediterranean it reaches roughly 100 cm fork length and about 12 kg (Collette and Nauen), with a maximum age of eight years. And one anatomical line from the same chapter explains its whole behaviour: “Swim bladder absent.” No swim bladder. It cannot stop, cannot hover, cannot hang there and inspect. It decides while passing — or not at all.
What it actually eats
Now the part that saves fishing days. In 2007 Falautano, Castriota, Finoia and Andaloro examined the stomachs of 187 little tunny from the central Mediterranean in the *Journal of the Marine Biological Association of the UK* (87: 999–1005), fish of 26.8 to 50.3 cm. The result: the diet was “predominately composed of fish, mainly *Maurolicus muelleri* and larval stages of teleost” — mostly fish, and above all Mueller’s pearlside (*Maurolicus muelleri*, a deep-sea hatchetfish of at most eight centimetres) and larval teleosts. Alongside them, well represented by frequency of occurrence, hyperiid amphipods (*Anchylomera blossevillei*, *Phrosina semilunata*). Read that again: a half-metre fish leading a school of a thousand and tearing the surface open had a stomach full of prey shorter than the leader knot on your plug. ⚠️ And then comes the line that makes it usable: “The smaller specimens feed mainly on adults of clupeiformes and larvae or other juvenile teleosts. For larger specimens, adult teleosts, crustaceans and cephalopods dominate.” Prey size grows with the fish. So there is no single correct lure size — there is one that fits the fish hunting in front of you.
How big is answered by where you stand
The second study turns the picture around, and that is exactly why it belongs here. Hajjej and colleagues worked through 622 stomachs from the Tunisian Mediterranean coast, fish of 19.2 to 97.8 cm fork length, taken in coastal areas. There teleosts occurred in the majority of stomachs with a total relative importance of 97.3 %, and the most important prey was the round sardinella *Sardinella aurita*, followed by *Boops boops* and *Sardina pilchardus*. That is a completely different order of size from pearlsides and amphipods — and it is the same species. The difference is not biology, it is location: out in open water it eats what drifts there (small); close inshore it eats what swims there (considerably bigger). For you that means the question “what lure size?” has no catalogue answer. It has a place answer. Look at what is actually fleeing along your edge, and put yourself next to that, not above it. García and Posada also showed in 2013 that the species is a daytime feeder (“daylight feed behaviour”) and sits at a trophic level of 4.49: a genuine apex predator that lives on small stuff all its life.
- One size down beats any amount of extra action. When the water boils and nothing happens, the first thing to change is not speed and not colour — it is size. Go down until the lure looks like whatever is dying out there.
- Do not count your lure, count the bait. The studies do not hand you a shop measurement, they hand you a method: watch what comes out of the water and match its size before you match anything else.
- Bigger fish, bigger prey. A school of smaller tunny is on larvae and juveniles; a school of big ones will also take adult fish, crustaceans and squid. When the backs are broad you may go up — not before.
- No swim bladder, so it decides in passing. It cannot stop and inspect. A lure that stalls or flutters does not become “more interesting”, it gets missed. Pull it through, evenly, without a pause.
- Current before area. ICCAT names swift currents, shoals, thermal fronts and upwellings. The seam where two waters meet is worth more with this fish than any wide open bay.
- Daylight, not dusk. García and Posada describe daytime feeding. Fish this predator like a pike-perch and you are out by several hours.
And now the paperwork, because there is an asymmetry here that hardly anyone knows. ⚠️ EU: Regulation (EU) 2019/1241 lists the minimum conservation reference sizes for the Mediterranean in Annex IX Part A. Among them: mackerel (*Scomber* spp.) 18 cm, horse mackerel (*Trachurus* spp.) 15 cm, anchovy 9 cm, sardine 11 cm — almost exactly the fish this predator hunts. Euthynnus is not there. Neither is *Sarda*, nor *Auxis*. In the Mediterranean the EU therefore protects the prey with a minimum size and the predator with none. That is not a licence; it is a pointer that national rules are what count. Croatia shows how fine-grained they get — with two lists and two different answers for the same fish. The *Pravilnik o sportskom i rekreacijskom ribolovu na moru*, NN 48/2026 (8 May 2026, in force since 1 June 2026), requires in Article 11(1) that 23 species be marked by cutting off the lower part of the tail fin (“Ribe … koje se zadržavaju, a moraju se označiti odsijecanjem donjeg dijela repne peraje su:”) — among them *Sarda sarda* (palamida), but ⚠️ luc (*Euthynnus alletteratus*) is not on that list. In Annex 1, Table 1, by contrast — the species for which a catch record must be kept — it appears explicitly: “luc *Euthynnus alletteratus*”, right next to “palamida *Sarda sarda*” and “trup *Auxis rochei*”. And Article 8(1) still binds: “Maksimalno ograničenje ulova po ribolovcu propisano je Zakonom te je zabranjeno nastaviti obavljati ribolov nakon dostizanja tog ograničenja” — the maximum per angler is set in the Act, and after that you stop. ⚠️ One footnote on names that costs real fines: “trup” in Croatia means *Auxis rochei*, in Albania it means *Euthynnus alletteratus* — one word, two fish, two neighbouring coasts. And in Spanish bacoreta is this fish while melva is *Auxis*. Report by name instead of by species and you report the wrong thing.
Not the speed — the size
With this predator the question is not whether you are fast enough, but whether what you offer fits its prey image. One size down, pulled through evenly, on a current seam, in daylight — that is the whole difference between a boiling sea that ignores you and one that takes you along. Whether an edge produces at all today depends on water temperature, current, wind, fronts and season: on a lot of things that change hourly while the chart stays the same. That is exactly what the StrikeAhead app is built for: it reads your water with bite windows, weather and marine data, chart and depth contours, and learns from your catches so you fish the moment instead of guessing it. And because on this coast half the answer is knowing which bait is running right now, the second part is the shortcut — that knowledge is on no chart, it sits in somebody’s head. The app tells you when. StrikeAhead Pathfinder tells you with whom: our curated directory of fishing guides and skippers — every expert personally vetted, licence and insurance checked before listing, profiles built from real, verified catches out of the StrikeAhead logbook instead of advertising photos, no paid ranking, and no booking fee for you as an angler.