?Hippocampus
圖片參考:
http://upload.wikimedia.org/wikipedia/commons/thumb/4/4b/Hippocampus.jpg/200px-Hippocampus.jpg
Seahorse, Hippocampus sp.
Scientific classification
Kingdom:
Animalia
Phylum:
Chordata
Class:
Osteichthyes (bony fish)
Order:
Syngnathiformes
Family:
Syngnathidae
Genus:
Hippocampus
Cuvier (1816)[1]
Species
See text for species.
Seahorses are marine fish belonging to the genus Hippocampus of the family Syngnathidae, which also includes pipefish. They are found in temperate and tropical waters all over the world.
Seahorses range in size from 16 mm (the recently discovered Hippocampus denise [1]) to 35 cm. Seahorses and pipefishes are notable for being the only species in which the males become pregnant.
The seahorse is a true fish, with a dorsal fin located on the lower body and pectoral fins located on the head near their gills. Some species of seahorse are partly transparent, hence are often not spotted in aquariums despite being there and are also not often seen in pictures.
Seahorse populations have been endangered in recent years by overfishing. The seahorse is used in traditional Chinese herbology, and as many as 20 million seahorses may be caught each year and sold for this purpose. [2]
Import and export of seahorses has been controlled under CITES since May 15, 2004.
Sea dragons are close relatives of seahorses but have bigger bodies and leaf-like appendages which enable them to hide among floating seaweed or kelp beds. Sea dragons feed on larval fishes and amphipods, such as small shrimp-like crustaceans called mysids ("sea lice"), sucking up their prey with their small mouths. Many of these amphipods feed on red algae that thrives in the shade of the kelp forests where the sea dragons live.
Seahorses reproduce in an unusual way: the male becomes pregnant. Most seahorse species' pregnancies lasts approximately two to three weeks.
The male seahorse has a brood pouch where he carries eggs deposited by the female. The mating pair entwine their tails and the female aligns a long tube called an ovipositor with the male's pouch. The eggs move through the tube into the male's pouch where he then fertilizes them. The embryos develop in ten days to six weeks, depending on species and water conditions. When the male gives birth he pumps his tail until the baby seahorses emerge.
The male's pouch regulates salinity for the eggs, slowly increasing in the pouch to match the water outside as the eggs mature. Once the offspring hatch, the male releases them and does not care for them. Most will not consume their own offspring, however it isn't unheard of.
Once released, the offspring are independent of their parents. Some spend time among the ocean plankton developing before settling down. At times, the male seahorse may try to consume some of the previously released offspring. Other species (H. zosterae) hitch immediately and begin life in the benthos.
Seahorses are generally monogamous, though several species (H. abdominalis among them) are highly gregarious. In monogamous pairs, the male and female will greet one another with courtship displays in the morning and sometimes in the evening to reinforce their pair bond. They spend the rest of the day separate from each other hunting for food.
While many aquarium hobbyists keep seahorses as pets, seahorses collected from the wild do not tend to fare well in a home aquarium. They will only feed on live foods such as brine shrimp and are prone to stress in an aquarium, which lowers their immune systems and exposes them to diseases.