| Pipefish | |
|---|---|
 | |
| Alligator pipefish (Syngnathoides biaculeatus) | |
Scientific classification  | |
| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Actinopterygii |
| Order: | Syngnathiformes |
| Family: | Syngnathidae |
| Subfamily: | Syngnathinae Bonaparte, 1831 [1] |
| Genera | |
See text. | |
Pipefishes or pipe-fishes (Syngnathinae) are a subfamily of small fishes, which, together with the seahorses and seadragons ( Phycodurus and Phyllopteryx ), form the family Syngnathidae.
Pipefish look like straight-bodied seahorses with tiny mouths. The name is derived from the peculiar form of the snout, which is like a long tube, ending in a narrow and small mouth which opens upwards and is toothless. The body and tail are long, thin, and snake-like. They each have a highly modified skeleton formed into armored plating. This dermal skeleton has several longitudinal ridges, so a vertical section through the body looks angular, not round or oval as in the majority of other fishes. [2]
A dorsal fin is always present, and is the principal (in some species, the only) organ of locomotion. The ventral fins are consistently absent, and the other fins may or may not be developed. The gill openings are extremely small and placed near the upper posterior angle of the gill cover. [2]
Many are very weak swimmers in open water, moving slowly by means of rapid movements of the dorsal fin. Some species of pipefish have prehensile tails, as in seahorses. The majority of pipefishes have some form of a caudal fin (unlike seahorses), which can be used for locomotion. [2] See fish anatomy for fin descriptions. Some species of pipefish have more developed caudal fins, such as the group collectively known as flagtail pipefish, which are quite strong swimmers.[ citation needed ]
Most pipefishes are marine dwellers; only a few are freshwater species. They are abundant on coasts of the tropical and temperate zones. Most species of pipefish are usually 35–40 cm (14–15.5 in) in length and generally inhabit sheltered areas in coral reefs or seagrass beds.
Due to their lack of strong swimming ability pipefish are often found in shallow waters that are easily disturbed by industrial runoffs and human recreation. Shorelines are also affected by boats and drag lines that move shoreline sediment. These disturbances cause a decrease in seagrasses and eelgrasses that are vital in pipefish habitats. The pipefish's narrow range distribution indictes that they are less able to adapt to new habitats or habitat change.
Another factor that affects pipefish populations is their use in traditional Chinese medicine (TCM) remedies, despite the lack of evidence of efficacy beyond placebo. Syngnathidae in general are in high demand for pseudo-scientific medicinal cures but pipefish are even more exploited because of a belief in their higher level of potency (because they are longer than the more common variety of seahorses).
The aquarium trade of pipefish has also increased in recent years.
Pipefishes, like their seahorse relatives, leave most of the parenting duties to the male, which provides all of the postzygotic care for its offspring, supplying them with nutrients and oxygen through a placenta-like connection. [4] It broods the offspring either on distinct region of its body or in a brood pouch. Brood pouches vary significantly among different species of pipefish, but all contain a small opening through which female eggs can be deposited. The location of the brood pouch can be along the entire underside of the pipefish or just at the base of the tail, as with seahorses. [5] Pipefish in the genus Syngnathus have a brood pouch with a ventral seam that can completely cover all of their eggs when sealed. In males without these pouches, eggs adhere to a strip of soft skin on the ventral surface of their bodies that does not contain any exterior covering. [6] The evolution of male brooding in pipefish is thought to be a result of the reproductive advantage granted to pipefish ancestors that learned to deposit their eggs onto the males, who could escape predation and protect them. [7] Furthermore, the ability to transfer immune information from both the mother (in the egg) and the father (in the pouch), unlike other chordates in which only the mother can transfer immune information, is believed to have an additive beneficial effect on offspring immunity. [7]
Courtship between male and female pipefish involves lengthy and complicated shows of display. For example, in Syngnathus typhle , copulation is always preceded by a ritualized dance by both sexes. The dance involves very conspicuous wriggling and shaking motions, especially in comparison to the species' otherwise extremely secretive lifestyle. Under the threat or presence of a predator, pipefish are more reluctant to perform their dances. In addition, when risk of predation is high, they copulate less frequently, dance less per copulation, and females transfer more eggs per copulation. Although S. thyphle males normally prefer to mate with larger females, they mate randomly when potentially threatened by predators. [8] Furthermore, in Corythoichthys haematopterus, similar ritualized mating dances were hypothesized to aid in reproductive synchronization, by allowing the female to assess male willingness to spawn so her eggs are not wasted. [9]
During pipefish copulation, which signifies the termination of the courtship dance, the female transfers her eggs through a small ovipositor into the male brood pouch or onto the special patch of skin on the male's ventral body surface. While the eggs are being transferred, the mating pair rises through the water until implantation is complete. At this point, the male assumes an S-shaped posture and fertilizes the eggs, all the while descending back down the water column. [10] Males possessing brood pouches release their sperm directly into them; the pouches are then vigorously shaken. The ventral seams are not opened until weeks later when the male pipefish give birth. [6]
A physical limit exists for the number of eggs a male pipefish can carry, so males are considered to be the limiting sex. Females can often produce more eggs than males can accommodate inside their brood pouches, resulting in more eggs than can be cared for. Other factors may restrict female reproductive success, including male pregnancy length and energy investment in progeny. [11]
Because the pipefish embryos develop within the male, feeding on nutrients supplied by him, male pipefish invest more energy than females in each zygote. Additionally, they invest more energy per unit time than females throughout each breeding season. [12] As a result, some males may consume their embryos rather than continuing to rear them under situations to regain energy in which their bodies are exhausted of resources. Pregnant male pipefish can absorb nutrients from their broods, in a manner very similar to filial cannibalism found in many other families of fish. The smallest eggs in a brood of various egg sizes usually have lower survival rates than larger ones due to the larger eggs having a longer-lasting food source (absent contributions from the father), hence they more likely to develop into mature adults. In other instances, some pipefishes may consume the embryos of mates that seem less fit or desirable, as each male generally copulates with more than one female. [10]
Young are born free-swimming with relatively little or no yolk sac, and begin feeding immediately. From the time they hatch, they are independent of their parents, which at that time may view them as food. Some fry have short larval stages and live as plankton for a short while. Others are fully developed but miniature versions of their parents, assuming the same behaviors as their parents immediately.
Pair bonding varies wildly between different species of pipefish. While some are monogamous or seasonally monogamous, others are not.
Many species exhibit polyandry, a breeding system in which one female mates with two or more males. This tends to occur with greater frequency in internal-brooding species of pipefishes than with external-brooding ones due to limitation in male brood capacity. [13] Polyandrous species are also more likely to have females with complex sexual signals such as ornaments. [14] For example, the polyandrous Gulf pipefish (Syngnathus scovelli) displays considerable sexual dimorphic characteristics such as larger ornament area and number, and body size. [15]
A seahorse is any of 46 species of small marine fish in the genus Hippocampus. "Hippocampus" comes from the Ancient Greek hippókampos (ἱππόκαμπος), itself from híppos (ἵππος) meaning "horse" and kámpos (κάμπος) meaning "sea monster" or "sea animal". Having a head and neck suggestive of a horse, seahorses also feature segmented bony armour, an upright posture and a curled prehensile tail. Along with the pipefishes and seadragons they form the family Syngnathidae.
The Syngnathidae is a family of fish which includes seahorses, pipefishes, and seadragons. The name is derived from Ancient Greek: σύν, meaning "together", and γνάθος, meaning "jaw". The fused jaw is one of the traits that the entire family have in common.
The common seadragon or weedy seadragon is a marine fish related to the seahorses. Adult common seadragons are a reddish colour, with yellow and purple markings; they have small leaf-like appendages that resemble kelp fronds providing camouflage and a number of short spines for protection. Males have narrower bodies and are darker than females. Seadragons have a long dorsal fin along the back and small pectoral fins on either side of the neck, which provide balance. Common seadragons can reach 45 cm (18 in) in length.
Male pregnancy is the incubation of one or more embryos or fetuses by organisms of the male sex in some species. Most species that reproduce by sexual reproduction are heterogamous—females producing larger gametes (ova) and males producing smaller gametes (sperm). In nearly all animal species, offspring are carried by the female until birth, but in fish of the family Syngnathidae, males perform that function.
The greater pipefish is a pipefish of the family Syngnathidae. It is a seawater fish and the type species of the genus Syngnathus.
Microphis is a genus of pipefishes within the family Syngnathidae. Members of this genus are notable among the Syngnathidae for residing in mainly fresh and brackish waters. Adults breed in coastal rivers, streams, or lakes, and fertilized eggs are carried by the male pipefish in a brood pouch extending along his entire ventral surface.
The black-striped pipefish is a species of fish in the family Syngnathidae. It is found in the eastern Atlantic from the southern Gulf of Biscay to Gibraltar, also in the Mediterranean and Black Seas. As the introduced species it is mentioned in the Caspian Sea and fresh waters of its basin.
Schultz's pipefish, Corythoichthys schultzi, is a pipefish of the family Syngnathidae.
The Hippocampinae are a subfamily of small marine fishes in the family Syngnathidae. Depending on the classification system used, it comprises either seahorses and pygmy pipehorses, or only seahorses.
The broadnosed pipefish or deepnosed pipefish is a fish of the family Syngnathidae. It is native to the Eastern Atlantic from Vardø in Norway, Baltic Sea and the British Isles at north to Morocco at south. It is also found in the Mediterranean Sea, Black Sea and Sea of Azov. It is common in the coastal shallow waters, usually on reefs with seagrasses. This species is notable for its "broad" snout, which is as deep as its body.
The dusky pipefish is a species of the pipefishes, widespread in the western Atlantic from the Bermuda, Chesapeake Bay, northern part of the Gulf of Mexico, Bahama, and the western Caribbean Sea to Panama in south. Marine subtropical demersal fish, which lives at the depth up to 22 metres (72 ft), usually up to 4 metres (13 ft). The maximal length of the fish is 25 centimetres (9.8 in).
The chain pipefish is a pipefish species. It inhabits the western Atlantic from Virginia, Bermuda and northern Gulf of Mexico to Campeche and Jamaica, but is absent from the Bahamas. It is a marine subtropical reef-associated fish, up to 38 cm length.
The Yucatán pipefish is a demersal fish species native to the Gulf of Mexico.
Halicampus is a genus of pipefishes of the family Syngnathidae, containing 12 described species.
Acentronura is a genus of pygmy pipehorse native to the Indian and Pacific oceans. The name is derived from the Greek ακεντρονουρα, or a-kentron-oura, and refers to the lack of a sting on the tail.
The high-body pipefish is a pipefish in the family Syngnathidae. These demersal fish are widespread in New Zealand and the Auckland Islands. It can be found in the vicinity of piers and wharves down to offshore depths of 62–120 metres (203–394 ft). They have been recorded from substrates consisting of bryozoan and coarse shell. The juveniles have been collected in surface plankton tows. They are ovoviviparous and the male bears the eggs in a brood pouch which is on the ventral side of the tail. Gravid males have been recorded from standard lengths of 9.95 centimetres (3.92 in).
The robust ghost pipefish, also known as the blue-finned ghost pipefish, Racek's ghost pipefish, robust-snouted ghost pipefish, or the squaretail ghost-pipefish, is a species of false pipefish belonging to the family Solenostomidae. Its appearance can vary greatly due to its ability to change colors over several hours, but the general body shape and fin shapes allow it to mimic a piece of seagrass.
Corythoichthys amplexus, known commonly as the brown-banded pipefish, is a species of marine fish in the family Syngnathidae.
Pregnancy has been traditionally defined as the period of time eggs are incubated in the body after the egg-sperm union. Although the term often refers to placental mammals, it has also been used in the titles of many international, peer-reviewed, scientific articles on fish, e.g. Consistent with this definition, there are several modes of reproduction in fish, providing different amounts of parental care. In ovoviviparity, there is internal fertilization and the young are born live but there is no placental connection or significant trophic (feeding) interaction; the mother's body maintains gas exchange but the unborn young are nourished by egg yolk. There are two types of viviparity in fish. In histotrophic viviparity, the zygotes develop in the female's oviducts, but she provides no direct nutrition; the embryos survive by eating her eggs or their unborn siblings. In hemotrophic viviparity, the zygotes are retained within the female and are provided with nutrients by her, often through some form of placenta.
Urocampus nanus, commonly known as the barbed pipefish, is a species of marine fish belonging to the family Syngnathidae. This family consists of 56 different genera and 320 species.
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