Halfbeak
Encyclopedia
The halfbeaks are a geographically widespread and numerically abundant family
of epipelagic fish
inhabiting warm waters around the world. The family Hemiramphidae is divided into two subfamilies, the primarily marine
Hemiramphinae and the freshwater
or estuarine
Zenarchopterinae. The halfbeaks are named for their distinctive jaws, in which the lower jaws are significantly longer than the upper jaws. The halfbeaks show an exceptionally wide range of reproductive
modes. These include egg-laying
, ovoviviparity
, and true vivipary
where the mother is connected to the developing embryos via a placenta
-like structure. In some of the livebearing
species, developing embryo
s are also known to exhibit oophagy
or intrauterine cannibalism
, where developing embryos feed on eggs or other embryos within the uterus
.
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 billfish
es, mackerel
s, and shark
s. Some halfbeaks are maintained as aquarium
fish.
was the first to scientifically describe a halfbeak, Esox
brasiliensis. In 1775 Peter Forsskål
described two more species
as Esox, Esox far and Esox marginatus. It was not until 1816 that Georges Cuvier
created the genus
Hemiramphus; from then on, all three were classified as Hemiramphus. In 1859, Gill erected Hemiramphidae, deriving its name from Hemiramphus, the family's type genus
. The name comes from the Greek
hemi, meaning half, and rhamphos, meaning beak or bill.
The family Hemiramphidae is currently divided into two subfamilies, the Hemiramphinae and the Zenarchopterinae, each containing about half the known species. A 2004 review of the family recognized two subfamilies, 13 genera, and 117 species and subspecies. More recently, Hemiramphidae lost the genus Oxyporhamphus to Exocoetidae.
The Hemiramphinae are primarily marine
and found in the Atlantic, Pacific, and Indian Ocean
s, though some inhabit estuaries
and river
s. The Zenarchopterinae are confined to the Indo-West Pacific
zoogeographic
region, an area running from East Africa
to the Caroline Islands
. The Zenarchopterinaeexhibit strong sexual dimorphism
, practicing internal fertilisation, and in some cases ovoviviparous or viviparous. Three genera in this subfamily are exclusively freshwater fish
and several, such as the wrestling halfbeak
, have become commonly traded aquarium fish
. Some authors recognize Zenarchopterinae as a separate family (Zenarchopteridae).
at Monte Bolca, Italy. 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.
Phylogeny of the halfbeaks. The halfbeak family
Hemiramphidae (Zenarchopterinae + Hemirhamphinae) is paraphyletic.
The phylogeny of the halfbeaks is in a state of flux.
On the one hand, there is little question that they are most closely related to three other families of streamlined, surface water fishes: the flyingfish
es, needlefish
es, and sauries
. Traditionally, these four families have been taken to together comprise the order Beloniformes
. The halfbeaks and flyingfishes are considered to form one group, the superfamily Exocoetoidea, and the needlefishes and sauries another, the superfamily Scomberesocoidea.
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.
Within the subfamily Hemiramphinae, the "flying halfbeak" genus Oxyporhamphus has proved to be particularly problematic; while morphologically
closer to the flyingfishes, molecular evidence places it with Hemiramphus and Euleptorhamphus. Together, these three genera form the sister group
to the flyingfish family. The other two hemiramphine genera Hyporhamphus and Arrhamphus form another clade of less clear placement.
Rather than being closely related to the flyingfishes, the subfamily Zenarchopterinae appears to be the sister group of the needlefish
es and sauries
. These is based on the pharyngeal jaw apparatus, sperm
ultrastructure, and molecular evidence. However, this hypothesis has awkward implications for how the morphological evolution of the group is understood, because the fused pharyngeal plate has been considered reliably diagnostic of the halfbeak family. Furthermore, the existing theory that because juvenile needlefish pass through a developmental
stage where the lower jaw is longer than the upper jaw (the so-called "halfbeak stage") the theory that halfbeaks are paedomorphic needlefish is untenable. In fact the unequal lengths of the upper and lower jaws of halfbeaks appears to be the basal
condition, with needlefish being relatively derived
in comparison.
The halfbeaks are elongate, streamlined fish adapted to living in open water. Halfbeaks range in size from 4 centimetres (1.6 in) standard length (SL)
in Hemirhamphodon tengah to over 40 centimetres (15.7 in) SL in the case of Euleptorhampus viridis
. The scales
are relatively large, cycloid (smooth), and easily detached. There are no spines in the fins. A distinguishing characteristic is that the third pair of upper pharyngeal bones are anklylosed (fused) into a plate. Halfbeaks are one of several fish families that lack a stomach
, all of which possess a pharyngeal jaw apparatus (pharyngeal mill). Most species have an extended lower jaw, at least as juveniles, though this feature may be lost as the fish mature, as with Chriodorus
, for example.
As is typical for surface dwelling, open water fish, most species are silvery, darker above and lighter below, an example of countershading
. The tip of the lower jaw is bright red or orange in most species. Small colored patches, particularly among males, are only found on the fins and the tip of the beak.
Halfbeaks carry several adaptations to feeding at the water surface. The eyes and nostrils are at the top of the head and the upper jaw is mobile, but not the lower jaw. Combined with their streamlined shape and the concentration of fins towards the back (similar to that of a pike
), these adaptations allow halfbeaks to locate, catch, and swallow food items very effectively.
is apparent in some species. Males of the ovovivaparous and vivaparous species all have a modified anal fin, the andropodium, similar to the gonopodium of poecilid livebearers, used to deliver sperm to the females. Although most egg laying species mate by shedding the milt
externally, as is typical for bony fish, at least some practice internal fertilization: male Zenarchopterus
use a modified anal fin to direct sperm into the genital opening of the female prior to spawning.
Besides modifications to the anal fin, other differences include size, coloration, and the beak's length or shape. Female Normorhamphus are much larger than males but aren't as brightly colored and have shorter beaks. By contrast, male Hemirhamphodon
are larger than females, and some species, such as Hemirhamphodon pogonognathus, also have a long beard-like tassel on the end of the beak.
Halfbeaks inhabit warm seas, predominantly at the surface, in the Atlantic, Indian
, and Pacific oceans. A small number are found in estuaries
and some species, including all the species in the genera Dermogenys
, Hemirhamphodon
, Nomorhamphus
, and Tondanichthys are confined to freshwaters. Most species of marine halfbeaks are known from continental coastlines, but some extend into the western and central Pacific, and one species is endemic to New Zealand
. Hemiramphus is a worldwide marine genus.
The freshwater halfbeaks all occur in freshwater or estuaries in the Indo-West Pacific
region. There is a particularly high concentration of species on the island of Celebes
.
s feeding on algae
; marine plants such as seagrass
es; plankton
; invertebrates such as pteropods
and crustaceans; and smaller fishes. 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 shark
s, and so are a key link between trophic level
s.
The freshwater species are more predatory than the marine species, and typically orient themselves into the current and take aquatic insect larva
e, such as midge
larvae, and small insect
s, such as flies
that have fallen on the surface of the water, particularly mosquito
es and spider
s.
forage fish
. The southern sea garfish Hyporhamphus melanochir for example is found in sheltered bays, coastal seas, estuaries around southern Australia in waters down to a depth of 20 metres (65.6 ft). These fish school near the surface at night but swim closer to the sea floor during the day, particularly among beds of seagrass
es. Genetic analysis of the different sub-populations
of the eastern sea garfish Hyporhamphus melanochir in South Australia
n coastal waters reveals that there is a small but consistent migration of individuals among theme, sufficient to keep them genetically homogeneous.
Freshwater halfbeaks vary in social behavior from open water schooling fish similar to the marine halfbeaks, as with species of Zenarchopterus
, through to much more aggressive and combative fishes, as is best known from the "wrestling" halfbeaks of genus
Dermogenys
. These non-schoolers prefer to lurk among aquatic plant
s such as reeds
, dead trees, and artificial structures of various types; from where they wait for small prey animals to drift by or alight on the surface, before darting from their hiding place to hunt. Notably, they feed extensively on female mosquitoes that are laying their eggs in the water, making them much better at mosquito control that species like guppies and mosquitofish
that only take mosquito larvae.
Some marine halfbeaks, including Euleptorhamphus velox and Euleptorhamphus viridis, are known for their ability to jump out of the water and glide over the surface for considerable distances, and have consequently sometimes been called flying halfbeaks.
Halfbeaks exhibit a remarkably wide variety of reproductive modes ranging from straightforward egg-laying (oviparity) through to various form of livebearing
(ovoviviparity
and viviparity). There is a taxonomic split in this however: all Hemiramphinae are egg-layers, while many of the Zenarchopterinae are either ovoviviparous or viviparous.
meadows of Florida Bay
. The eggs of Hemiramphus brasiliensis and H. balao are typically 1.5–2.5 mm (0.0590551181102362–0.0984251968503937 in) in diameter and have attaching filaments. They hatch when they grow to about 4.8–11 mm (0.188976377952756–0.433070866141732 in) in diameter. Hyporhamphus melanochir eggs are slightly larger, around 2.9 mm (0.114173228346457 in) in diameter, and are unusually large when they hatch, being up to 8.5 mm (0.334645669291339 in) in size.
Relatively little is known about the ecology of juvenile marine halfbeaks, though estuarine habitats seem to be favored by at least some species. The southern sea garfish Hyporhamphus melanochir grows rapidly at first, attaining a length of up to 30 cm (11.8 in) in the first three years, after which point growth slows. This species lives for a maximum age of about 9 years, at which point the fish reach up to 40 cm (15.7 in) and weigh about 0.35 kg (0.771617917647071 lb).
The freshwater halfbeaks of the genera Dermogenys, Hemirhamphodon, and Nomorhamphus are all livebearers, that is, they produce well-developed free-swimming young. However, there is a great deal of variation in the details. Meisner and Burns identified no fewer than five distinct modes of viviparity and ovovivparity
in freshwater halfbeaks:
As with other livebearing fish, freshwater halfbeaks produce small broods of large offspring compared with egg-laying species of similar size, with broods of around ten to twenty, typically 10 – long.
, though small fisheries for them exist in some places, for example in South Australia
where fisheries target the southern sea garfish (Hyporhamphus melanochir). 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 with haul nets. They are utilized fresh, dried, smoked, or salted, and they are considered good eating. However, even where halfbeaks are targeted by fisheries, they tend to be of secondary importance compared with other edible fish species.
In some localities significant bait fish
eries exist to supply sport fishermen
. One study of a bait fishery in Florida that targets Hemiramphus brasiliensis and Hemiramphus balao suggests that despite increases in the size of the fishery the population is stable and the annual catch is valued at around $500,000.
, in particular fight vigorously. Battles may end in injuries. In some Asia
n countries gamblers bet on the outcomes, as they do with Siamese fighting fish
.
Some of the smaller freshwater species are kept as ornamental aquarium
fish., particularly genera Dermogenys and Nomorhamphus, but also Hemirhamphodon and Zenarchopterus, less commonly.
To be kept successfully, halfbeaks require an aquarium with plenty of space at the surface. Depth is not critical, so a wide tank is better than a deep one. They are sensitive to low oxygen levels
but are otherwise relatively hardy, except that they are intolerant of sudden changes in salinity
, pH
, hardness
, or temperature
. Consequently, they must be introduced to a new aquarium gently, and small but frequent water changes are best, so the water chemistry does not change suddenly. A few species, most notably Dermogenys pusillius, have traditionally been kept in slightly brackish water, though some authors aver that those found in brackish water are estuarine juveniles. Most traded species of Nomorhamphus and Hemirhamphodon prefer soft, neutral to slightly acidic, freshwater conditions.
Halfbeaks are sensitive and shocks like sudden changes in illumination can evoke frantic swimming activity. They may crash into the glass, injuring their beaks, or jump out of the tank. Such beak injuries usually heal within a few weeks. They will eat insect larvae such as bloodworms readily, as well as crustacean eggs, shrimp, fruit flies, and small pieces of chopped white fish. Halfbeaks sometimes eat flake foods as well. Some aquarists also offer them tiny pieces of algae wafer on the basis that most species are omnivorous in the wild, and so plant food probably suits them.
Halfbeaks breed in captivity, but despite being livebearers
not easily. Miscarriages are common, particularly if the females are stressed (for example, by being moved to another aquarium). Once the fry have been born, the large babies eat newly hatched brine shrimp
, small live foods such as daphnia
, and powdered flake
.
assessing their risk of extinction. None of these species are traded as aquarium fish. Most are simply rare in the wild, and consequently at particular risk from habitat destruction
.
Family (biology)
In biological classification, family is* a taxonomic rank. Other well-known ranks are life, domain, kingdom, phylum, class, order, genus, and species, with family fitting between order and genus. As for the other well-known ranks, there is the option of an immediately lower rank, indicated by the...
of epipelagic fish
Fish
Fish are a paraphyletic group of organisms that consist of all gill-bearing aquatic vertebrate animals that lack limbs with digits. Included in this definition are the living hagfish, lampreys, and cartilaginous and bony fish, as well as various extinct related groups...
inhabiting warm waters around the world. The family Hemiramphidae is divided into two subfamilies, the primarily marine
Marine (ocean)
Marine is an umbrella term. As an adjective it is usually applicable to things relating to the sea or ocean, such as marine biology, marine ecology and marine geology...
Hemiramphinae and the freshwater
Fresh Water
Fresh Water is the debut album by Australian rock and blues singer Alison McCallum, released in 1972. Rare for an Australian artist at the time, it came in a gatefold sleeve...
or estuarine
Estuary
An estuary is a partly enclosed coastal body of water with one or more rivers or streams flowing into it, and with a free connection to the open sea....
Zenarchopterinae. The halfbeaks are named for their distinctive jaws, in which the lower jaws are significantly longer than the upper jaws. The halfbeaks show an exceptionally wide range of reproductive
Biological reproduction
Reproduction is the biological process by which new "offspring" individual organisms are produced from their "parents". Reproduction is a fundamental feature of all known life; each individual organism exists as the result of reproduction...
modes. These include egg-laying
Oviparity
Oviparous animals are animals that lay eggs, with little or no other embryonic development within the mother. This is the reproductive method of most fish, amphibians, reptiles, all birds, the monotremes, and most insects, some molluscs and arachnids....
, ovoviviparity
Ovoviviparity
Ovoviviparity, ovovivipary, or ovivipary, is a mode of reproduction in animals in which embryos develop inside eggs that are retained within the mother's body until they are ready to hatch...
, and true vivipary
Vivipary
Vivipary has two different meanings. In animals, it means development of the embryo inside the body of the mother, eventually leading to live birth, as opposed to laying eggs...
where the mother is connected to the developing embryos via a placenta
Placenta
The placenta is an organ that connects the developing fetus to the uterine wall to allow nutrient uptake, waste elimination, and gas exchange via the mother's blood supply. "True" placentas are a defining characteristic of eutherian or "placental" mammals, but are also found in some snakes and...
-like structure. In some of the livebearing
Live-bearing aquarium fish
Live-bearing aquarium fish, often simply called livebearers, are fish that retain the eggs inside the body and give birth to live, free-swimming young.-Common aquarium livebearers:...
species, developing embryo
Embryo
An embryo is a multicellular diploid eukaryote in its earliest stage of development, from the time of first cell division until birth, hatching, or germination...
s are also known to exhibit oophagy
Oophagy
Oophagy , literally "egg eating", is the practice of embryos feeding on eggs produced by the ovary while still inside the mother's uterus. The word oophagy is formed from the classical Greek ᾠόν and classical Greek φᾱγεῖν ....
or intrauterine cannibalism
Intrauterine Cannibalism
Intrauterine Cannibalism is the first studio album by American brutal death metal band Malignancy.-Track listing:# "Rotten Seed" — 3:16# "Intrauterine Cannibalism" — 1:42# "Intestinal Sodomy" — 2:22# "Internal Corruption" — 1:48...
, where developing embryos feed on eggs or other embryos within the uterus
Uterus
The uterus or womb is a major female hormone-responsive reproductive sex organ of most mammals including humans. One end, the cervix, opens into the vagina, while the other is connected to one or both fallopian tubes, depending on the species...
.
Though not commercially important
Fishing
Fishing is the activity of trying to catch wild fish. Fish are normally caught in the wild. Techniques for catching fish include hand gathering, spearing, netting, angling and trapping....
themselves, these forage fish
Forage fish
Forage fish, also called prey fish or bait fish, are small fish which are preyed on by larger predators for food. Predators include other larger fish, seabirds and marine mammals. Typical ocean forage fish feed near the base of the food chain on plankton, often by filter feeding...
support artisanal fisheries
Artisan fishing
Artisan fishing is a term used to describe small scale low-technology commercial or subsistence fishing practices. The term particularly applies to coastal or island ethnic groups using traditional techniques such as rod and tackle, arrows and harpoons, throw nets and drag nets, and traditional...
and local markets worldwide. They are also fed upon by other commercially important predatory fishes, such as billfish
Billfish
The term billfish is applied to a number of different large, predatory fish characterised by their large size and their long, sword-like bill. Billfish include the sailfish and marlin, which make up the family Istiophoridae, and the swordfish, sole member of the family Xiphiidae...
es, mackerel
Mackerel
Mackerel is a common name applied to a number of different species of fish, mostly, but not exclusively, from the family Scombridae. They may be found in all tropical and temperate seas. Most live offshore in the oceanic environment but a few, like the Spanish mackerel , enter bays and can be...
s, and shark
Shark
Sharks are a type of fish with a full cartilaginous skeleton and a highly streamlined body. The earliest known sharks date from more than 420 million years ago....
s. Some halfbeaks are maintained as aquarium
Aquarium
An aquarium is a vivarium consisting of at least one transparent side in which water-dwelling plants or animals are kept. Fishkeepers use aquaria to keep fish, invertebrates, amphibians, marine mammals, turtles, and aquatic plants...
fish.
Taxonomy
In 1775, Carolus LinnaeusCarolus Linnaeus
Carl Linnaeus , also known after his ennoblement as , was a Swedish botanist, physician, and zoologist, who laid the foundations for the modern scheme of binomial nomenclature. He is known as the father of modern taxonomy, and is also considered one of the fathers of modern ecology...
was the first to scientifically describe a halfbeak, Esox
Esox
Esox is a genus of freshwater fish, the only living genus in the family Esocidae — the esocids which were endemic to North America, Europe and Eurasia during the Paleogene through present.The type species is E. lucius, the northern pike...
brasiliensis. In 1775 Peter Forsskål
Peter Forsskål
Peter Forsskål, sometimes spelled Pehr Forsskål, Peter Forskaol, Petrus Forskål or Pehr Forsskåhl, was a Swedish explorer, orientalist, naturalist and an apostle of Carl Linnaeus.-Early life:...
described two more species
Species
In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are...
as Esox, Esox far and Esox marginatus. It was not until 1816 that Georges Cuvier
Georges Cuvier
Georges Chrétien Léopold Dagobert Cuvier or Jean Léopold Nicolas Frédéric Cuvier , known as Georges Cuvier, was a French naturalist and zoologist...
created the genus
Genus
In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...
Hemiramphus; from then on, all three were classified as Hemiramphus. In 1859, Gill erected Hemiramphidae, deriving its name from Hemiramphus, the family's type genus
Biological type
In biology, a type is one particular specimen of an organism to which the scientific name of that organism is formally attached...
. The name comes from the Greek
Ancient Greek
Ancient Greek is the stage of the Greek language in the periods spanning the times c. 9th–6th centuries BC, , c. 5th–4th centuries BC , and the c. 3rd century BC – 6th century AD of ancient Greece and the ancient world; being predated in the 2nd millennium BC by Mycenaean Greek...
hemi, meaning half, and rhamphos, meaning beak or bill.
The Hemiramphinae are primarily marine
Marine biology
Marine biology is the scientific study of organisms in the ocean or other marine or brackish bodies of water. Given that in biology many phyla, families and genera have some species that live in the sea and others that live on land, marine biology classifies species based on the environment rather...
and found in the Atlantic, Pacific, and Indian Ocean
Indian Ocean
The Indian Ocean is the third largest of the world's oceanic divisions, covering approximately 20% of the water on the Earth's surface. It is bounded on the north by the Indian Subcontinent and Arabian Peninsula ; on the west by eastern Africa; on the east by Indochina, the Sunda Islands, and...
s, though some inhabit estuaries
Estuary
An estuary is a partly enclosed coastal body of water with one or more rivers or streams flowing into it, and with a free connection to the open sea....
and river
River
A river is a natural watercourse, usually freshwater, flowing towards an ocean, a lake, a sea, or another river. In a few cases, a river simply flows into the ground or dries up completely before reaching another body of water. Small rivers may also be called by several other names, including...
s. The Zenarchopterinae are confined to the Indo-West Pacific
Indo-West Pacific
The Indo-West Pacific, or IWP, is a zoogeographical region spanning the entire Indian Ocean including the Red Sea and the Pacific Ocean as far as the Caroline Islands but short of the Marshall Islands...
zoogeographic
Zoogeography
Zoogeography is the branch of the science of biogeography that is concerned with the geographic distribution of animal species.-External links:*: A course outline and collection of Web resources by Dr. Taylor, UBC...
region, an area running from East Africa
East Africa
East Africa or Eastern Africa is the easterly region of the African continent, variably defined by geography or geopolitics. In the UN scheme of geographic regions, 19 territories constitute Eastern Africa:...
to the Caroline Islands
Caroline Islands
The Caroline Islands are a widely scattered archipelago of tiny islands in the western Pacific Ocean, to the north of New Guinea. Politically they are divided between the Federated States of Micronesia in the eastern part of the group, and Palau at the extreme western end...
. The Zenarchopterinaeexhibit strong sexual dimorphism
Sexual dimorphism
Sexual dimorphism is a phenotypic difference between males and females of the same species. Examples of such differences include differences in morphology, ornamentation, and behavior.-Examples:-Ornamentation / coloration:...
, practicing internal fertilisation, and in some cases ovoviviparous or viviparous. Three genera in this subfamily are exclusively freshwater fish
Freshwater fish
Freshwater fish are fish that spend some or all of their lives in freshwater, such as rivers and lakes, with a salinity of less than 0.05%. These environments differ from marine conditions in many ways, the most obvious being the difference in levels of salinity...
and several, such as the wrestling halfbeak
Wrestling halfbeak
The wrestling halfbeak, Dermogenys pusilla, also known as Malayan halfbeak is a member of the halfbeak family found in the fresh and brackish waters of rivers and coastal regions in South-East Asia, in Singapore, Thailand, Indonesia, Thailand, Malaysia, Borneo and Sumatra...
, have become commonly traded aquarium fish
Fishkeeping
Fishkeeping is a popular hobby concerned with keeping fish in a home aquarium or garden pond. There is also a fishkeeping industry, as a branch of agriculture.-Types of fishkeeping systems:...
. Some authors recognize Zenarchopterinae as a separate family (Zenarchopteridae).
Evolution
The halfbeaks' fossil record extends into the Lower Tertiary. The earliest known halfbeak is Brachyrhamphus bolcensis from the EoceneEocene
The Eocene Epoch, lasting from about 56 to 34 million years ago , is a major division of the geologic timescale and the second epoch of the Paleogene Period in the Cenozoic Era. The Eocene spans the time from the end of the Palaeocene Epoch to the beginning of the Oligocene Epoch. The start of the...
at Monte Bolca, Italy. Apart from differences in the length of the upper and lower jaws, recent
Holocene
The Holocene is a geological epoch which began at the end of the Pleistocene and continues to the present. The Holocene is part of the Quaternary period. Its name comes from the Greek words and , meaning "entirely recent"...
and fossil halfbeaks are distinguished by the fusion of the third pair of upper pharyngeal
Pharyngeal
The word pharyngeal, meaning to do with the pharynx or throat, may refer to:* Pharynx, for pharyngeal anatomy* Pharyngeal muscles**Superior pharyngeal constrictor muscle** Middle pharyngeal constrictor muscle** Inferior pharyngeal constrictor muscle...
bones into a plate.
Phylogeny
Family (biology)
In biological classification, family is* a taxonomic rank. Other well-known ranks are life, domain, kingdom, phylum, class, order, genus, and species, with family fitting between order and genus. As for the other well-known ranks, there is the option of an immediately lower rank, indicated by the...
Hemiramphidae (Zenarchopterinae + Hemirhamphinae) is paraphyletic.
The phylogeny of the halfbeaks is in a state of flux.
On the one hand, there is little question that they are most closely related to three other families of streamlined, surface water fishes: the flyingfish
Flyingfish
Exocoetidae, is a family of marine fish in the order Beloniformes of class Actinopterygii. Fish of this family are known as flying fish. There are about 64 species grouped in seven to nine genera.- Etymology :...
es, needlefish
Needlefish
Needlefish are piscivorous fishes primarily associated with very shallow marine habitats or the surface of the open sea. Some genera include species found in marine, brackish, and freshwater environments while a few genera are confined to freshwater rivers and streams, including Belonion,...
es, and sauries
Saury
Sauries are fish of the family Scomberesocidae. There are two genera, each containing two species. The name Scomberesocidae is derived from the Greek, skombros = tuna/mackerel, and esox = nursery of salmon....
. Traditionally, these four families have been taken to together comprise the order Beloniformes
Beloniformes
The Beloniformes are an order of five families of freshwater and marine ray-finned fish: the Adrianichthyidae ; Belonidae ; Exocoetidae ; Hemiramphidae ; and the Scomberesocidae...
. The halfbeaks and flyingfishes are considered to form one group, the superfamily Exocoetoidea, and the needlefishes and sauries another, the superfamily Scomberesocoidea.
On the other hand, recent studies have demonstrated that rather than forming a single monophyletic group (a clade
Clade
A clade is a group consisting of a species and all its descendants. In the terms of biological systematics, a clade is a single "branch" on the "tree of life". The idea that such a "natural group" of organisms should be grouped together and given a taxonomic name is central to biological...
), 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.
Within the subfamily Hemiramphinae, the "flying halfbeak" genus Oxyporhamphus has proved to be particularly problematic; while morphologically
Morphology (biology)
In biology, morphology is a branch of bioscience dealing with the study of the form and structure of organisms and their specific structural features....
closer to the flyingfishes, molecular evidence places it with Hemiramphus and Euleptorhamphus. Together, these three genera form the sister group
Cladistics
Cladistics is a method of classifying species of organisms into groups called clades, which consist of an ancestor organism and all its descendants . For example, birds, dinosaurs, crocodiles, and all descendants of their most recent common ancestor form a clade...
to the flyingfish family. The other two hemiramphine genera Hyporhamphus and Arrhamphus form another clade of less clear placement.
Rather than being closely related to the flyingfishes, the subfamily Zenarchopterinae appears to be the sister group of the needlefish
Needlefish
Needlefish are piscivorous fishes primarily associated with very shallow marine habitats or the surface of the open sea. Some genera include species found in marine, brackish, and freshwater environments while a few genera are confined to freshwater rivers and streams, including Belonion,...
es and sauries
Saury
Sauries are fish of the family Scomberesocidae. There are two genera, each containing two species. The name Scomberesocidae is derived from the Greek, skombros = tuna/mackerel, and esox = nursery of salmon....
. These is based on the pharyngeal jaw apparatus, sperm
Sperm
The term sperm is derived from the Greek word sperma and refers to the male reproductive cells. In the types of sexual reproduction known as anisogamy and oogamy, there is a marked difference in the size of the gametes with the smaller one being termed the "male" or sperm cell...
ultrastructure, and molecular evidence. However, this hypothesis has awkward implications for how the morphological evolution of the group is understood, because the fused pharyngeal plate has been considered reliably diagnostic of the halfbeak family. Furthermore, the existing theory that because juvenile needlefish pass through a developmental
Developmental biology
Developmental biology is the study of the process by which organisms grow and develop. Modern developmental biology studies the genetic control of cell growth, differentiation and "morphogenesis", which is the process that gives rise to tissues, organs and anatomy.- Related fields of study...
stage where the lower jaw is longer than the upper jaw (the so-called "halfbeak stage") the theory that halfbeaks are paedomorphic needlefish is untenable. In fact the unequal lengths of the upper and lower jaws of halfbeaks appears to be the basal
Basal (phylogenetics)
In phylogenetics, a basal clade is the earliest clade to branch in a larger clade; it appears at the base of a cladogram.A basal group forms an outgroup to the rest of the clade, such as in the following example:...
condition, with needlefish being relatively derived
Derived
In phylogenetics, a derived trait is a trait that is present in an organism, but was absent in the last common ancestor of the group being considered. This may also refer to structures that are not present in an organism, but were present in its ancestors, i.e. traits that have undergone secondary...
in comparison.
Morphology
Fish measurement
Fish measurement refers to the measuring of the length of individual fish and of various parts of their anatomy. These data are used in many areas of ichthyology, including taxonomy and fisheries biology.-Overall length:...
in Hemirhamphodon tengah to over 40 centimetres (15.7 in) SL in the case of Euleptorhampus viridis
Euleptorhamphus
Euleptorhamphus is a genus of halfbeaks in the order Beloniformes. It includes two species, the flying halfbeak, E. velox, and the ribbon halfbeak, E. viridis.Both of these species are marine. E...
. The scales
Scale (zoology)
In most biological nomenclature, a scale is a small rigid plate that grows out of an animal's skin to provide protection. In lepidopteran species, scales are plates on the surface of the insect wing, and provide coloration...
are relatively large, cycloid (smooth), and easily detached. There are no spines in the fins. A distinguishing characteristic is that the third pair of upper pharyngeal bones are anklylosed (fused) into a plate. Halfbeaks are one of several fish families that lack a stomach
Stomach
The stomach is a muscular, hollow, dilated part of the alimentary canal which functions as an important organ of the digestive tract in some animals, including vertebrates, echinoderms, insects , and molluscs. It is involved in the second phase of digestion, following mastication .The stomach is...
, all of which possess a pharyngeal jaw apparatus (pharyngeal mill). Most species have an extended lower jaw, at least as juveniles, though this feature may be lost as the fish mature, as with Chriodorus
Chriodorus
The hardhead halfbeak, Chriodorus atherinoides, is a species of halfbeak found across in coastal waters of the western Western Atlantic region from the southern USA to Mexico including Cuba and the Bahamas. This species is euryhaline and frequently migrates up rivers. Of no commercial value. Unlike...
, for example.
As is typical for surface dwelling, open water fish, most species are silvery, darker above and lighter below, an example of countershading
Countershading
Countershading, or Thayer's Law, is a form of camouflage. Countershading, in which an animal’s pigmentation is darker dorsally, is often thought to have an adaptive effect of reducing conspicuous shadows cast on the ventral region of an animal’s body...
. The tip of the lower jaw is bright red or orange in most species. Small colored patches, particularly among males, are only found on the fins and the tip of the beak.
Halfbeaks carry several adaptations to feeding at the water surface. The eyes and nostrils are at the top of the head and the upper jaw is mobile, but not the lower jaw. Combined with their streamlined shape and the concentration of fins towards the back (similar to that of a pike
Esox
Esox is a genus of freshwater fish, the only living genus in the family Esocidae — the esocids which were endemic to North America, Europe and Eurasia during the Paleogene through present.The type species is E. lucius, the northern pike...
), these adaptations allow halfbeaks to locate, catch, and swallow food items very effectively.
Sexual dimorphism
Sexual dimorphismSexual dimorphism
Sexual dimorphism is a phenotypic difference between males and females of the same species. Examples of such differences include differences in morphology, ornamentation, and behavior.-Examples:-Ornamentation / coloration:...
is apparent in some species. Males of the ovovivaparous and vivaparous species all have a modified anal fin, the andropodium, similar to the gonopodium of poecilid livebearers, used to deliver sperm to the females. Although most egg laying species mate by shedding the milt
Milt
Milt is the seminal fluid of fish, mollusks, and certain other water-dwelling animals who reproduce by spraying this fluid, which contains the sperm, onto roe .-Milt as food:...
externally, as is typical for bony fish, at least some practice internal fertilization: male Zenarchopterus
Zenarchopterus
Zenarchopterus is a genus of fish in the Hemiramphidae family.It contains the following species:* Zenarchopterus alleni* Zenarchopterus buffonis* Zenarchopterus caudovittatus* Zenarchopterus clarus* Zenarchopterus dispar* Zenarchopterus dunckeri...
use a modified anal fin to direct sperm into the genital opening of the female prior to spawning.
Besides modifications to the anal fin, other differences include size, coloration, and the beak's length or shape. Female Normorhamphus are much larger than males but aren't as brightly colored and have shorter beaks. By contrast, male Hemirhamphodon
Hemirhamphodon
Hemirhamphodon is a genus of halfbeak found in peaty and lowland forest streams in Southeast Asia. Six species are known, all relatively small, the largest species being about 10 cm in length...
are larger than females, and some species, such as Hemirhamphodon pogonognathus, also have a long beard-like tassel on the end of the beak.
Range and habitat
Indian Ocean
The Indian Ocean is the third largest of the world's oceanic divisions, covering approximately 20% of the water on the Earth's surface. It is bounded on the north by the Indian Subcontinent and Arabian Peninsula ; on the west by eastern Africa; on the east by Indochina, the Sunda Islands, and...
, and Pacific oceans. A small number are found in estuaries
Estuary
An estuary is a partly enclosed coastal body of water with one or more rivers or streams flowing into it, and with a free connection to the open sea....
and some species, including all the species in the genera Dermogenys
Dermogenys
The freshwater and brackish water halfbeaks of the genus Dermogenys are widely distributed in South and Southeast Asia from India to Indonesia. They are all viviparous, producing small clutches of up to 30 fry that closely resemble the adults, except they are much smaller, around 10 to 15 mm in...
, Hemirhamphodon
Hemirhamphodon
Hemirhamphodon is a genus of halfbeak found in peaty and lowland forest streams in Southeast Asia. Six species are known, all relatively small, the largest species being about 10 cm in length...
, Nomorhamphus
Nomorhamphus
The freshwater halfbeaks of the genus Nomorhamphus are widely distributed in Southeast Asia, in particular the islands of the Philippines, Indonesia, and Sulawesi. They are all viviparous, producing small clutches of around a dozen fry about 10 to 15 mm long at birth. Females are generally larger...
, and Tondanichthys are confined to freshwaters. Most species of marine halfbeaks are known from continental coastlines, but some extend into the western and central Pacific, and one species is endemic to New Zealand
New Zealand
New Zealand is an island country in the south-western Pacific Ocean comprising two main landmasses and numerous smaller islands. The country is situated some east of Australia across the Tasman Sea, and roughly south of the Pacific island nations of New Caledonia, Fiji, and Tonga...
. Hemiramphus is a worldwide marine genus.
The freshwater halfbeaks all occur in freshwater or estuaries in the Indo-West Pacific
Indo-West Pacific
The Indo-West Pacific, or IWP, is a zoogeographical region spanning the entire Indian Ocean including the Red Sea and the Pacific Ocean as far as the Caroline Islands but short of the Marshall Islands...
region. There is a particularly high concentration of species on the island of Celebes
Sulawesi
Sulawesi is one of the four larger Sunda Islands of Indonesia and is situated between Borneo and the Maluku Islands. In Indonesia, only Sumatra, Borneo, and Papua are larger in territory, and only Java and Sumatra have larger Indonesian populations.- Etymology :The Portuguese were the first to...
.
Feeding
Marine halfbeaks are omnivoreOmnivore
Omnivores are species that eat both plants and animals as their primary food source...
s feeding on algae
Algae
Algae are a large and diverse group of simple, typically autotrophic organisms, ranging from unicellular to multicellular forms, such as the giant kelps that grow to 65 meters in length. They are photosynthetic like plants, and "simple" because their tissues are not organized into the many...
; marine plants such as seagrass
Seagrass
Seagrasses are flowering plants from one of four plant families , all in the order Alismatales , which grow in marine, fully saline environments.-Ecology:...
es; plankton
Plankton
Plankton are any drifting organisms that inhabit the pelagic zone of oceans, seas, or bodies of fresh water. That is, plankton are defined by their ecological niche rather than phylogenetic or taxonomic classification...
; invertebrates such as pteropods
Sea butterfly
Sea butterflies, also known as Thecosomata or flapping snails, are a taxonomic suborder of small pelagic swimming sea snails. These are holoplanktonic opisthobranch gastropod mollusks in the informal group Opisthobranchia. They include some of the world's most abundant gastropod species.This group...
and crustaceans; and smaller fishes. 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
Fishing
Fishing is the activity of trying to catch wild fish. Fish are normally caught in the wild. Techniques for catching fish include hand gathering, spearing, netting, angling and trapping....
fish, such as billfish
Billfish
The term billfish is applied to a number of different large, predatory fish characterised by their large size and their long, sword-like bill. Billfish include the sailfish and marlin, which make up the family Istiophoridae, and the swordfish, sole member of the family Xiphiidae...
, mackerel
Mackerel
Mackerel is a common name applied to a number of different species of fish, mostly, but not exclusively, from the family Scombridae. They may be found in all tropical and temperate seas. Most live offshore in the oceanic environment but a few, like the Spanish mackerel , enter bays and can be...
, and shark
Shark
Sharks are a type of fish with a full cartilaginous skeleton and a highly streamlined body. The earliest known sharks date from more than 420 million years ago....
s, and so are a key link between trophic level
Trophic level
The trophic level of an organism is the position it occupies in a food chain. The word trophic derives from the Greek τροφή referring to food or feeding. A food chain represents a succession of organisms that eat another organism and are, in turn, eaten themselves. The number of steps an organism...
s.
The freshwater species are more predatory than the marine species, and typically orient themselves into the current and take aquatic insect larva
Larva
A larva is a distinct juvenile form many animals undergo before metamorphosis into adults. Animals with indirect development such as insects, amphibians, or cnidarians typically have a larval phase of their life cycle...
e, such as midge
Midge
A midge is a very small, two-winged flying insect. "Midge" may also refer to:-Real:* Midge Costanza , American politician* Mildred Gillars , aka "Midge", American broadcaster of Nazi propaganda during World War II...
larvae, and small insect
Insect
Insects are a class of living creatures within the arthropods that have a chitinous exoskeleton, a three-part body , three pairs of jointed legs, compound eyes, and two antennae...
s, such as flies
Fly
True flies are insects of the order Diptera . They possess a pair of wings on the mesothorax and a pair of halteres, derived from the hind wings, on the metathorax...
that have fallen on the surface of the water, particularly mosquito
Mosquito
Mosquitoes are members of a family of nematocerid flies: the Culicidae . The word Mosquito is from the Spanish and Portuguese for little fly...
es and spider
Spider
Spiders are air-breathing arthropods that have eight legs, and chelicerae with fangs that inject venom. They are the largest order of arachnids and rank seventh in total species diversity among all other groups of organisms...
s.
Behavior
Marine halfbeaks are typically pelagic schoolingShoaling and schooling
In biology, any group of fish that stay together for social reasons are said to be shoaling , and if, in addition, the group is swimming in the same direction in a coordinated manner, they are said to be schooling . In common usage, the terms are sometimes used rather loosely...
forage fish
Forage fish
Forage fish, also called prey fish or bait fish, are small fish which are preyed on by larger predators for food. Predators include other larger fish, seabirds and marine mammals. Typical ocean forage fish feed near the base of the food chain on plankton, often by filter feeding...
. The southern sea garfish Hyporhamphus melanochir for example is found in sheltered bays, coastal seas, estuaries around southern Australia in waters down to a depth of 20 metres (65.6 ft). These fish school near the surface at night but swim closer to the sea floor during the day, particularly among beds of seagrass
Seagrass
Seagrasses are flowering plants from one of four plant families , all in the order Alismatales , which grow in marine, fully saline environments.-Ecology:...
es. Genetic analysis of the different sub-populations
Population biology
Population biology is a study of populations of organisms, especially the regulation of population size, life history traits such as clutch size, and extinction...
of the eastern sea garfish Hyporhamphus melanochir in South Australia
South Australia
South Australia is a state of Australia in the southern central part of the country. It covers some of the most arid parts of the continent; with a total land area of , it is the fourth largest of Australia's six states and two territories.South Australia shares borders with all of the mainland...
n coastal waters reveals that there is a small but consistent migration of individuals among theme, sufficient to keep them genetically homogeneous.
Freshwater halfbeaks vary in social behavior from open water schooling fish similar to the marine halfbeaks, as with species of Zenarchopterus
Zenarchopterus
Zenarchopterus is a genus of fish in the Hemiramphidae family.It contains the following species:* Zenarchopterus alleni* Zenarchopterus buffonis* Zenarchopterus caudovittatus* Zenarchopterus clarus* Zenarchopterus dispar* Zenarchopterus dunckeri...
, through to much more aggressive and combative fishes, as is best known from the "wrestling" halfbeaks of genus
Genus
In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...
Dermogenys
Dermogenys
The freshwater and brackish water halfbeaks of the genus Dermogenys are widely distributed in South and Southeast Asia from India to Indonesia. They are all viviparous, producing small clutches of up to 30 fry that closely resemble the adults, except they are much smaller, around 10 to 15 mm in...
. These non-schoolers prefer to lurk among aquatic plant
Aquatic plant
Aquatic plants are plants that have adapted to living in aquatic environments. They are also referred to as hydrophytes or aquatic macrophytes. These plants require special adaptations for living submerged in water, or at the water's surface. Aquatic plants can only grow in water or in soil that is...
s such as reeds
Reed bed
Reed beds are natural habitats found in floodplains, waterlogged depressions andestuaries. Reed beds are part of a succession from young reed colonising open water or wet ground through a gradation of increasingly dry ground...
, dead trees, and artificial structures of various types; from where they wait for small prey animals to drift by or alight on the surface, before darting from their hiding place to hunt. Notably, they feed extensively on female mosquitoes that are laying their eggs in the water, making them much better at mosquito control that species like guppies and mosquitofish
Mosquitofish
The mosquitofish is a species of freshwater fish, also commonly, if ambiguously, known by its generic name, gambusia. It is sometimes called the western mosquitofish, to distinguish it from the eastern mosquitofish . It is a member of the family Poeciliidae of order Cyprinodontiformes...
that only take mosquito larvae.
Some marine halfbeaks, including Euleptorhamphus velox and Euleptorhamphus viridis, are known for their ability to jump out of the water and glide over the surface for considerable distances, and have consequently sometimes been called flying halfbeaks.
Reproduction
Live-bearing aquarium fish
Live-bearing aquarium fish, often simply called livebearers, are fish that retain the eggs inside the body and give birth to live, free-swimming young.-Common aquarium livebearers:...
(ovoviviparity
Ovoviviparity
Ovoviviparity, ovovivipary, or ovivipary, is a mode of reproduction in animals in which embryos develop inside eggs that are retained within the mother's body until they are ready to hatch...
and viviparity). There is a taxonomic split in this however: all Hemiramphinae are egg-layers, while many of the Zenarchopterinae are either ovoviviparous or viviparous.
Oviparity in the Hemiramphinae
Hemiramphinae species are all external fertilizers. They are usually egg-layers and often produce relatively small numbers of fairly large eggs for fish of their size, typically in shallow coastal waters, such as the seagrassSeagrass
Seagrasses are flowering plants from one of four plant families , all in the order Alismatales , which grow in marine, fully saline environments.-Ecology:...
meadows of Florida Bay
Florida Bay
Florida Bay is the bay located between the southern end of the Florida mainland and the Florida Keys. Its area is variously stated to be , or , or . Nearly all of Florida Bay is included in Everglades National Park. The southern edge, along the Florida Keys is in the Florida Keys National Marine...
. The eggs of Hemiramphus brasiliensis and H. balao are typically 1.5–2.5 mm (0.0590551181102362–0.0984251968503937 in) in diameter and have attaching filaments. They hatch when they grow to about 4.8–11 mm (0.188976377952756–0.433070866141732 in) in diameter. Hyporhamphus melanochir eggs are slightly larger, around 2.9 mm (0.114173228346457 in) in diameter, and are unusually large when they hatch, being up to 8.5 mm (0.334645669291339 in) in size.
Relatively little is known about the ecology of juvenile marine halfbeaks, though estuarine habitats seem to be favored by at least some species. The southern sea garfish Hyporhamphus melanochir grows rapidly at first, attaining a length of up to 30 cm (11.8 in) in the first three years, after which point growth slows. This species lives for a maximum age of about 9 years, at which point the fish reach up to 40 cm (15.7 in) and weigh about 0.35 kg (0.771617917647071 lb).
Viviparity in the Zenarchopterinae
Ovoviviparity
Ovoviviparity, ovovivipary, or ovivipary, is a mode of reproduction in animals in which embryos develop inside eggs that are retained within the mother's body until they are ready to hatch...
in freshwater halfbeaks:
| Type | Egg location | Superfetation Superfetation Superfetation is the simultaneous occurrence of more than one stage of developing embryo in the same animal. In mammals it manifests as the formation of a fetus from a different menstrual cycle while another embryo is already present in the uterus... (sperm storage) | Yolk sac | Maternal connection | Brood Offspring In biology, offspring is the product of reproduction, of a new organism produced by one or more parents.Collective offspring may be known as a brood or progeny in a more general way... s per mating | |Example | |Notes |
|---|---|---|---|---|---|---|---|
| 1 | ovarian follicle Ovarian follicle Ovarian follicles are the basic units of female reproductive biology, each of which is composed of roughly spherical aggregations of cells found in the ovary. They contain a single oocyte . These structures are periodically initiated to grow and develop, culminating in ovulation of usually a single... |
No | Large | None | |||
| Southeast Asia Southeast Asia Southeast Asia, South-East Asia, South East Asia or Southeastern Asia is a subregion of Asia, consisting of the countries that are geographically south of China, east of India, west of New Guinea and north of Australia. The region lies on the intersection of geological plates, with heavy seismic... n populations of Dermogenys pusilla |
|||||||
| 2 | ovarian follicle Ovarian follicle Ovarian follicles are the basic units of female reproductive biology, each of which is composed of roughly spherical aggregations of cells found in the ovary. They contain a single oocyte . These structures are periodically initiated to grow and develop, culminating in ovulation of usually a single... |
Yes | Small | via the coelomic cavity Body cavity By the broadest definition, a body cavity is any fluid-filled space in a multicellular organism. However, the term usually refers to the space located between an animal’s outer covering and the outer lining of the gut cavity, where internal organs develop... and pericardial sac Pericardium The pericardium is a double-walled sac that contains the heart and the roots of the great vessels.-Layers:... |
3 | Dermogenys pusilla from Sabah and Dermogenys orientalis | |
| 3 | ovarian follicle Ovarian follicle Ovarian follicles are the basic units of female reproductive biology, each of which is composed of roughly spherical aggregations of cells found in the ovary. They contain a single oocyte . These structures are periodically initiated to grow and develop, culminating in ovulation of usually a single... , briefly, then along full ovary length |
Yes | Small | Via expanded belly sac | 2 | Dermogenys viviparus | |
| 4 | ovarian follicle Ovarian follicle Ovarian follicles are the basic units of female reproductive biology, each of which is composed of roughly spherical aggregations of cells found in the ovary. They contain a single oocyte . These structures are periodically initiated to grow and develop, culminating in ovulation of usually a single... , briefly, then along full ovary length |
No | Large | No | Nomorhamphus megarrhamphus, Nomorhamphus weberi, and Nomorhamphus towoetii | ||
| 5 | ovarian follicle Ovarian follicle Ovarian follicles are the basic units of female reproductive biology, each of which is composed of roughly spherical aggregations of cells found in the ovary. They contain a single oocyte . These structures are periodically initiated to grow and develop, culminating in ovulation of usually a single... , briefly, then along full ovary length |
Yes | Small | Partial | Nomorhamphus ebrardtii | Late-stage embryos are oophagous Oophagy Oophagy , literally "egg eating", is the practice of embryos feeding on eggs produced by the ovary while still inside the mother's uterus. The word oophagy is formed from the classical Greek ᾠόν and classical Greek φᾱγεῖν .... (eating eggs and small embryos) like sharks and a few other fishes. |
As with other livebearing fish, freshwater halfbeaks produce small broods of large offspring compared with egg-laying species of similar size, with broods of around ten to twenty, typically 10 – long.
Halfbeak fisheries
Halfbeaks are not a major target for commercial fisheriesFishing
Fishing is the activity of trying to catch wild fish. Fish are normally caught in the wild. Techniques for catching fish include hand gathering, spearing, netting, angling and trapping....
, though small fisheries for them exist in some places, for example in South Australia
South Australia
South Australia is a state of Australia in the southern central part of the country. It covers some of the most arid parts of the continent; with a total land area of , it is the fourth largest of Australia's six states and two territories.South Australia shares borders with all of the mainland...
where fisheries target the southern sea garfish (Hyporhamphus melanochir). 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 with haul nets. They are utilized fresh, dried, smoked, or salted, and they are considered good eating. However, even where halfbeaks are targeted by fisheries, they tend to be of secondary importance compared with other edible fish species.
In some localities significant bait fish
Bait fish
Bait fish are small fish caught for use as bait to attract large predatory fish, particularly game fish. Species used are typically those that are common and breed rapidly, making them easy to catch and in regular supply. Examples of marine bait fish are anchovies, halfbeaks such as ballyhoo, and...
eries exist to supply sport fishermen
Game fish
Game fish are fish pursued for sport by recreational anglers. They can be freshwater or marine fish. Game fish can be eaten after being caught, though increasingly anglers practise catch and release to improve fish populations. Some game fish are also targeted commercially, particularly...
. One study of a bait fishery in Florida that targets Hemiramphus brasiliensis and Hemiramphus balao suggests that despite increases in the size of the fishery the population is stable and the annual catch is valued at around $500,000.
Gambling
They are small and generally peaceful towards other species, although males can be aggressive to one another. Dermogenys pusillius, the wrestling halfbeakWrestling halfbeak
The wrestling halfbeak, Dermogenys pusilla, also known as Malayan halfbeak is a member of the halfbeak family found in the fresh and brackish waters of rivers and coastal regions in South-East Asia, in Singapore, Thailand, Indonesia, Thailand, Malaysia, Borneo and Sumatra...
, in particular fight vigorously. Battles may end in injuries. In some Asia
Asia
Asia is the world's largest and most populous continent, located primarily in the eastern and northern hemispheres. It covers 8.7% of the Earth's total surface area and with approximately 3.879 billion people, it hosts 60% of the world's current human population...
n countries gamblers bet on the outcomes, as they do with Siamese fighting fish
Betta
Betta is a large genus of small, often colorful, freshwater ray-finned fishes in the gourami family . The type species is B. picta, the spotted betta.By far the best known Betta species, however, is B...
.
In the aquarium
Aquarium
An aquarium is a vivarium consisting of at least one transparent side in which water-dwelling plants or animals are kept. Fishkeepers use aquaria to keep fish, invertebrates, amphibians, marine mammals, turtles, and aquatic plants...
fish., particularly genera Dermogenys and Nomorhamphus, but also Hemirhamphodon and Zenarchopterus, less commonly.
To be kept successfully, halfbeaks require an aquarium with plenty of space at the surface. Depth is not critical, so a wide tank is better than a deep one. They are sensitive to low oxygen levels
Oxygen saturation
Oxygen saturation or dissolved oxygen is a relative measure of the amount of oxygen that is dissolved or carried in a given medium. It can be measured with a dissolved oxygen probe such as an oxygen sensor or an optode in liquid media, usually water.It has particular significance in medicine and...
but are otherwise relatively hardy, except that they are intolerant of sudden changes in salinity
Salinity
Salinity is the saltiness or dissolved salt content of a body of water. It is a general term used to describe the levels of different salts such as sodium chloride, magnesium and calcium sulfates, and bicarbonates...
, pH
PH
In chemistry, pH is a measure of the acidity or basicity of an aqueous solution. Pure water is said to be neutral, with a pH close to 7.0 at . Solutions with a pH less than 7 are said to be acidic and solutions with a pH greater than 7 are basic or alkaline...
, hardness
Hard water
Hard water is water that has high mineral content . Hard water has high concentrations of Ca2+ and Mg2+ ions. Hard water is generally not harmful to one's health but can pose serious problems in industrial settings, where water hardness is monitored to avoid costly breakdowns in boilers, cooling...
, or temperature
Temperature
Temperature is a physical property of matter that quantitatively expresses the common notions of hot and cold. Objects of low temperature are cold, while various degrees of higher temperatures are referred to as warm or hot...
. Consequently, they must be introduced to a new aquarium gently, and small but frequent water changes are best, so the water chemistry does not change suddenly. A few species, most notably Dermogenys pusillius, have traditionally been kept in slightly brackish water, though some authors aver that those found in brackish water are estuarine juveniles. Most traded species of Nomorhamphus and Hemirhamphodon prefer soft, neutral to slightly acidic, freshwater conditions.
Halfbeaks are sensitive and shocks like sudden changes in illumination can evoke frantic swimming activity. They may crash into the glass, injuring their beaks, or jump out of the tank. Such beak injuries usually heal within a few weeks. They will eat insect larvae such as bloodworms readily, as well as crustacean eggs, shrimp, fruit flies, and small pieces of chopped white fish. Halfbeaks sometimes eat flake foods as well. Some aquarists also offer them tiny pieces of algae wafer on the basis that most species are omnivorous in the wild, and so plant food probably suits them.
Halfbeaks breed in captivity, but despite being livebearers
Live-bearing aquarium fish
Live-bearing aquarium fish, often simply called livebearers, are fish that retain the eggs inside the body and give birth to live, free-swimming young.-Common aquarium livebearers:...
not easily. Miscarriages are common, particularly if the females are stressed (for example, by being moved to another aquarium). Once the fry have been born, the large babies eat newly hatched brine shrimp
Brine shrimp
Artemia is a genus of aquatic crustaceans known as brine shrimp. Artemia, the only genus in the family Artemiidae, has changed little externally since the Triassic period...
, small live foods such as daphnia
Daphnia
Daphnia are small, planktonic crustaceans, between 0.2 and 5 mm in length. Daphnia are members of the order Cladocera, and are one of the several small aquatic crustaceans commonly called water fleas because of their saltatory swimming style...
, and powdered flake
Fish flake
A fish flake is a platform built on poles and spread with boughs for drying cod-fish on the foreshore of fishing villages and small towns in rural Newfoundland, Canada. Spelling variations for fish flake in Newfoundland include flek, fleyke, fleake, flaik and fleack...
.
Conservation status
A small number of freshwater halfbeaks are listed in various categories on the IUCN Red ListIUCN Red List
The IUCN Red List of Threatened Species , founded in 1963, is the world's most comprehensive inventory of the global conservation status of biological species. The International Union for Conservation of Nature is the world's main authority on the conservation status of species...
assessing their risk of extinction. None of these species are traded as aquarium fish. Most are simply rare in the wild, and consequently at particular risk from habitat destruction
Habitat destruction
Habitat destruction is the process in which natural habitat is rendered functionally unable to support the species present. In this process, the organisms that previously used the site are displaced or destroyed, reducing biodiversity. Habitat destruction by human activity mainly for the purpose of...
.
- Dermogenys megarramphus – Lower Risk, Near Threatened
- Dermogenys weberi – Vulnerable
- Nomorhamphus celebensis – Data Deficient
- Nomorhamphus towoeti – Vulnerable
- Tondanichthys kottelati – Vulnerable
- Zenarchopterus alleni – Data Deficient
- Zenarchopterus robertsi – Lower Risk, Least Concern
See also
- Live-bearing aquarium fishLive-bearing aquarium fishLive-bearing aquarium fish, often simply called livebearers, are fish that retain the eggs inside the body and give birth to live, free-swimming young.-Common aquarium livebearers:...
- USS Halfbeak (SS-352)USS Halfbeak (SS-352)USS Halfbeak , a Balao-class submarine, was a ship of the United States Navy named for the halfbeak, a garlike fish with a beak formed by an extension of the lower jaw, found in warmer seas....
American submarineSubmarineA submarine is a watercraft capable of independent operation below the surface of the water. It differs from a submersible, which has more limited underwater capability...
named after these fish