Black-barred halfbeak

The easiest way to identify this species is to look at its jaws. FishBase describes a greatly prolonged, beak-like lower jaw and a short, triangular upper jaw without scales; the dorsal and anal fins sit far back on the body, and the lower lobe of the tail fin is longer than the upper. The CIESM Atlas of Exotic Fishes in the Mediterranean Sea adds that the tip of the lower jaw is red and the upper lobe of the tail fin is yellow. FishBase gives the colour as a bluish back and silvery flanks, with 3 to 9, usually 4–6, vertical bars on the sides. This is where you need to be careful: the CIESM Atlas notes that in the Mediterranean population these blackish marks, commonly used to tell the species from its close relatives, are often faded or missing altogether. The distinguishing feature the atlas points to is the upper jaw: halfbeaks of the genus Hyporhamphus have scales on it, while in H. far it is naked. The same source notes that the first Mediterranean record was made under the name Hemiramphus marginatus. The Turkish name of this species in FishBase’s record for Türkiye is ‘yarımgaga balığı’, while WoRMS gives ‘ibikli çomak balığı’. ‘Külah balığı’ belongs to a different fish: FishBase lists that name for Fistularia commersonii, the bluespotted cornetfish (/en/turler/kulah-baligi).

WoRMS places the species in the family Hemiramphidae of the order Beloniformes, and its home range is the Indo-West Pacific. FishBase gives its distribution as running from the Red Sea and East Africa to Samoa, north to the Ryukyu Islands and south to northern Australia and New Caledonia, and notes that it has entered the eastern Mediterranean through the Suez Canal. According to the same source it lives in coastal waters, in areas rich in vegetation and on sand flats, at depths of 0–6 metres; the CIESM Atlas likewise describes it as a fish of inshore surface waters. The CIESM Atlas dates the first Mediterranean record to 1927, on the coast of Palestine; records from Syria, from Rhodes in 1938 and later from Egypt and Tunisia followed, and the species has also reached the coast of Algeria and Lampedusa in Italy. According to the atlas it is very abundant in the eastern basin as far as the Strait of Sicily; in the Levant its large schools are caught mainly with purse seines and occasionally with trammel nets. For Türkiye, the list of alien species that Çinar and colleagues published in PLOS ONE in 2021 gives the first observation year as 1942 for the Mediterranean (Levantine) coast and 2009 for the Aegean, and classes the species as ‘established’. The Aegean record is described in a note by Akça and Bilecenoğlu published in Mediterranean Marine Science in 2010: on 10 November 2009 a purse seiner caught a specimen of 14.6 centimetres standard length off Aslanburnu, Eski Foça, and seven more fish came from the same spot in December. The authors regard this as the northernmost record in the Aegean and a sign of an established population.

It is a schooling fish. The CIESM Atlas says it can leap out of the water and skitter across the surface with half of its body out of the water. On diet the sources diverge: FishBase says adults feed mainly on seagrasses and, to a lesser extent, on green algae and diatoms, while the CIESM Atlas gives its food as zooplankton and floating objects. On reproduction, CIESM writes that the eggs are large and attach to floating or bottom objects with adhesive filaments, while FishBase says the species breeds in estuaries. A study carried out in Egypt’s Bardawil lagoon and published in the Egyptian Journal of Aquatic Biology and Fisheries in 2019 found that spawning takes place between May and July and that the maximum lifespan is 4 years. FishBase records the species as one taken by commercial fisheries, targeted as a game fish and occasionally used as bait.