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Lesser amberjack (Seriola fasciata): the amberjack that came through Gibraltar — in the Mediterranean since 1993 and often mistaken for a young greater amberjack

If you catch a small amberjack under floating debris or at a fish aggregating device in the Mediterranean, you’ll usually take it for a young *Seriola dumerili*, the greater amberjack (the Italians’ ricciola). Sometimes it is a different species: *Seriola fasciata* — in English lesser amberjack, also false amberjack or little amberjack (English Wikipedia, GBIF), in Italian ricciola fasciata (Italian Wikipedia), in French sériole babiane, in Spanish medregal listado, in Portuguese charuteiro, in Danish lille ravfisk (GBIF). Unlike many newcomers to the Mediterranean, it did not come through the Suez Canal but, according to the CIESM Atlas, through the Strait of Gibraltar from the warm Atlantic. Here is how you recognise it, how far it has spread, how it lives — and why it is probably missing from the catch statistics.

1993: the first record came from the Balearics

It was described by Marcus Elieser Bloch in 1793, originally as *Scomber fasciatus* (English Wikipedia). Its home is the warm Atlantic: in the west from Massachusetts and Bermuda to Brazil, in the east around the Azores, Madeira, the Canary Islands, Cape Verde and St Helena (CIESM Atlas). The first Mediterranean record was published by Massutí and Stefanescu in 1993 in the *Journal of Fish Biology* — from the Balearic Islands. Twelve years later, an Italian research group led by Andaloro already put the question in the title: *“A recent colonist?”*

How to recognise it

  • Small in the Mediterranean. Typical sizes here are 8–25 cm fork length; the largest Mediterranean specimen mentioned in the Atlas measured 29 cm. In the Atlantic it reaches 67.5 cm fork length and 4.6 kg (CIESM Atlas, FishBase).
  • Short lobe on the second dorsal fin. This is the key feature: in adults, the raised front lobe of the second dorsal fin is only 11–13 % of fork length and usually 10–15 % shorter than the pectoral fin. In *S. dumerili* it is about as long as the pectoral fin or slightly longer (13–18 %), in *S. rivoliana* longer still (19–22 %) (CIESM Atlas).
  • Narrow end of the upper jaw. The rear end of the upper jaw is relatively slender in *S. fasciata*, medium to broad in *S. dumerili* and very broad in *S. rivoliana* (CIESM Atlas). Italian Wikipedia puts it vividly: in the ricciola this end of the jaw is as high and wide as the eye, in *S. fasciata* it is low.
  • Juveniles barred — right into the fins. Below about 20 cm fork length they are yellow with seven dark, irregularly interrupted vertical bars; the third to seventh bars continue onto the membranes between the rays of the second dorsal and the anal fin, and an eighth, small bar sits at the end of the caudal peduncle. In young *S. dumerili* the bars, if present at all, do not extend onto these fin membranes (CIESM Atlas).
  • Adults dark pink to violet on the back, flanks lighter, belly white or silvery (CIESM Atlas). English Wikipedia also mentions a dark stripe from behind the eye to in front of the first dorsal fin and a relatively larger eye than in the greater amberjack.
  • No bony scutes along the lateral line, but moderately developed grooves on the caudal peduncle (CIESM Atlas) — this separates it from jacks and horse mackerels, whose lateral line is armoured.
  • More gill rakers: from about 20 cm fork length 23–27 in total, in *S. dumerili* and *S. carpenteri* 11–25 (CIESM Atlas). The ranges overlap — it is only a reliable sign at the upper end.

How far it has spread

After the Balearics, the CIESM Atlas lists records from the southern Tyrrhenian Sea, from Sicily and Lampedusa in the Strait of Sicily, from the Gulf of Lion, the Gulf of Gabès (Tunisia), from Sardinia, Rhodes, Israel (2009, the first record in the Levant), Malta, the Gulf of Antalya, Syria, Lebanon (both 2015) and Libya (2017). The years are those of the publications, not necessarily of the catches. English Wikipedia sums it up like this: in the western Mediterranean since 1993, from there eastwards from Sicily to the Levant.

Habitat, prey, spawning season

  • Adults live close to the bottom. Near the seabed up to the open water above it (benthopelagic), according to English Wikipedia at 55–130 m depth. Italian Wikipedia describes it as more coastal and less oceanic than the other amberjacks.
  • Juveniles hold under floating debris. Small juveniles live at the surface under drifting objects in the open sea or in offshore shelf waters (CIESM Atlas, FishBase). In the Sicilian waters of the Ionian Sea, according to Italian Wikipedia, they are often caught at fish aggregating devices (FADs) during the lampuga (dolphinfish) season.
  • Prey: cephalopods and fish (CIESM Atlas); FishBase lists squid and fish.
  • Probably spawns in summer (CIESM Atlas). The Atlas mentions catches of small juveniles in October and November and of roughly one-year-old fish in various parts of the Mediterranean.
  • Conservation status: Least Concern on the IUCN Red List. FishBase rates its vulnerability to fishing as moderate to high (47 out of 100).

Probably underestimated in the catch

According to the CIESM Atlas, it is often caught with purse seines, but its share of the commercial catch is likely underestimated — because it is probably often landed as *S. dumerili*. The Atlas cautiously rates its establishment success as “occasionally reported”. Italian Wikipedia, by contrast, describes an apparently fairly large population off Lampedusa. If you have a small amberjack in your hand, two glances can help: at the lobe of the second dorsal fin and — in juveniles — at the bars in the fins.

Where the sources disagree

  • How big does it get? FishBase and CIESM Atlas: up to 67.5 cm fork length (in the Atlantic). Italian Wikipedia: up to 75 cm. For the Mediterranean the Atlas gives a maximum of 29 cm. The usual size also differs: FishBase 50 cm total length, the Atlas 8–25 cm fork length for the Mediterranean.
  • How many spines in the first dorsal fin? CIESM Atlas: 8. FishBase: 9.
  • How deep does it live? English Wikipedia: 55–130 m. FishBase: 55–348 m.
  • What colour is it? CIESM Atlas: back dark pink or violet; Italian Wikipedia: dark with violet reflections. English Wikipedia: olive green or brownish.
  • How many bars, up to what size? CIESM Atlas: seven bars plus a small eighth on the caudal peduncle, in juveniles below about 20 cm. Italian Wikipedia: eight bars up to about 30 cm.
  • Rare or established? CIESM Atlas: occasionally reported. Italian Wikipedia: a fairly large population off Lampedusa, juveniles common at fish aggregating devices.
  • Where does it live in the eastern Atlantic? English Wikipedia: from Spain to Ghana. FishBase considers its distribution in the eastern Atlantic uncertain, because it used to be confused with *Seriola carpenteri*.

Three name traps

  • “Ricciola” almost always means the large species. In Italian catches the name stands for *S. dumerili*. That is exactly why the CIESM Atlas suspects that *S. fasciata* gets lost in the statistics.
  • The Guinean amberjack. The Atlas places *Seriola carpenteri* alongside *S. dumerili* in terms of features — broad jaw end, long fin lobe. FishBase names it as the reason why the eastern Atlantic distribution of *S. fasciata* is unclear.
  • Collective names. GBIF also lists plain “Amberjack” for *S. fasciata* and, in Spanish, “medregal” — names used for several amberjacks. And the Spanish name “boquerón”, also listed, usually refers to the anchovy in Spain.

Which leaves the question every article in this series starts with: when. With a predator that holds under floating debris as a juvenile and hunts squid and fish near the bottom as an adult, the right day matters more than any rig. Habitat, prey and features are listed above, and they are fixed. What changes every day are the conditions on your water — StrikeAhead calculates them and tells you when the trip is worth it. And because you don’t know the edges and rules of unfamiliar water from day one, StrikeAhead Pathfinder tells you with whom you head out: curated guides and skippers, personally verified before listing — licence and insurance —, with verified catches instead of advertising photos, no paid ranking and, for you as an angler, no booking fee. The app says when, Pathfinder with whom.