Halfbeak

Hemiramphidae is a family of fishes that are commonly called halfbeaks, spipe fish or spipefish. They are a geographically widespread and numerically abundant family of epipelagic fish inhabiting warm waters around the world. The halfbeaks are named for their distinctive jaws, in which the lower jaws are significantly longer than the upper jaws. The similar viviparous halfbeaks (family Zenarchopteridae) have often been included in this family.

Though not commercially important themselves, these forage fish support artisanal fisheries and local markets worldwide. They are also fed upon by other commercially important predatory fishes, such as billfishes, mackerels, and sharks.

Taxonomy

thumb|250px|left|Oxyporhamphus micropterus has been considered either a halfbeak or a flyingfish.

In 1758, Carl Linnaeus was the first to scientifically describe a halfbeak, Esox brasiliensis (now Hemiramphus brasiliensis). In 1775 Peter Forsskål described two more species as Esox, Esox far and Esox marginatus. In 1816, Georges Cuvier created the genus Hemiramphus; from then on, all three were classified as Hemiramphus. In 1859, Theodore Nicholas Gill erected the Hemiramphidae, deriving their name from Hemiramphus, the family's type genus.

Currently, eight genera (including 60 species) are placed within the family Hemiramphidae:

Arrhamphus Günther, 1866
Chriodorus Goode & Bean, 1882
Euleptorhamphus Gill, 1859
Hemiramphus Cuvier, 1816
Hyporhamphus Gill, 1859
Melapedalion Fowler, 1934
Oxyporhamphus Gill, 1864
Rhynchorhamphus Fowler, 1928

This family is primarily marine and found in the Atlantic, Pacific, and Indian Oceans, though some inhabit estuaries and rivers.

Evolution

The halfbeaks' fossil record extends into the Lower Tertiary. Apart from differences in the length of the upper and lower jaws, recent and fossil halfbeaks are distinguished by the fusion of the third pair of upper pharyngeal bones into a plate. Traditionally, these four families have been taken to comprise the order Beloniformes.

On the other hand, recent studies have demonstrated that rather than forming a single monophyletic group (a clade), the halfbeak family actually includes a number of lineages ancestral to the flyingfishes and the needlefishes. In other words, as traditionally defined, the halfbeak family is paraphyletic.

Morphology

thumbnail|right|Preserved specimen

The halfbeaks are elongated, streamlined fish adapted to living in open water. They can grow to over in standard length in the case of Euleptorhampus viridis. Their scales are relatively large, cycloid (smooth), and easily detached. No spines are in the fins.

Range and habitat

thumb|250px|right|A marine halfbeak, Hemiramphus balao

Halfbeaks inhabit warm seas, predominantly at the surface, in the Atlantic, Indian, and Pacific Oceans. For some subtropical species, at least, juveniles are more predatory than adults. Some tropical species feed on animals during the day and plants at night, while other species alternate between carnivory in the summer and herbivory in the winter. They are, in turn, eaten by many ecologically and commercially important fish, such as billfish, mackerel, and sharks, so are a key link between trophic levels.

Behavior

Marine halfbeaks are typically pelagic, schooling, forage fish.

Reproduction

Hemiramphidae species are all external fertilizers. The eggs of Hemiramphus brasiliensis and H. balao are typically in diameter and have attaching filaments. They hatch when they grow to about in diameter. and the eastern sea garfish (Hyporhamphus australis). Halfbeaks are caught by a variety of methods, including seines and pelagic trawls, dip-netting under lights at night, and haul nets.

In some localities, significant bait fisheries exist to supply sport fishermen.