Seahorse

Scientific classification

Kingdom: Animalia

Phylum: Chordata

Class: Actinopterygii

Subclass: Neopterygii

Infraclass: Teleostei

Order: Syngnathiformes

Family: Syngnathidae

Subfamily: Hippocampinae

Genus: Hippocampus
Rafinesque, 1810[1]




Seahorses is the fish genus Hippocampus within the family Syngnathidae, in order Syngnathiformes. Syngnathidae also includes the pipefishes. "Hippocampus" comes from the Ancient Greek hippos meaning "horse" and kampos meaning “sea monster”.
There are nearly 50 species of seahorse. They are mainly found in shallow tropical and temperate waters throughout the world. They prefer to live in sheltered areas such as seagrass beds, coral reefs, or mangroves. They bob around in sea grass meadows, mangrove stands, and coral reefs where they adopt murky brown and gray patterns to camouflage themselves among the sea grass. During social moments or in unusual surroundings, seahorses turn bright colors.
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Description
Seahorses are named for their equine profile. Although they are bony fish, they do not have scales, but rather a thin skin stretched over a series of bony plates arranged in rings throughout their body. Each species has a distinct number of rings. Seahorses swim upright, another characteristic that is not shared by their close pipefish relatives, which swim horizontally. Seahorses have a coronet on their head, which is distinct to each individual, much like a human fingerprint. They swim very poorly by using a dorsal fin, which they rapidly flutter and pectoral fins, located behind their eyes, which they use to steer. Seahorses have no caudal fin. Since they are poor swimmers, they are most likely to be found resting, with their prehensile tails wound around a stationary object. They have long snouts, which they use to suck up food, and eyes that can move independently of each other, much like a chameleon. Seahorses eat small shrimp, tiny fish, crustaceans and plankton.
Reproduction
The male seahorse is equipped with a brood pouch on the ventral, or front-facing, side. When mating, the female seahorse deposits up to 1,500 eggs in the male's pouch. The male carries the eggs for anywhere from 9 to 45 days until they emerge, expelling fully-developed, miniature seahorses in the water. Once the seahorse babies are released into the water, the male's role is done and he offers no further care. Throughout gestation, which in most species requires two to four weeks, his mate visits him daily for “morning greetings”. They interact for about 6 minutes, reminiscent of courtship. The female then swims away until the next morning, and the male returns to vacuuming up food through his snout.

Courtship
Before breeding, seahorses court for several days. Scientists believe the courtship behavior synchronizes the animals' movements so that the male can receive the eggs when the female is ready to deposit them. During this time they may change color, swim side by side holding tails or grip the same strand of sea grass with their tails and wheel around in unison in what is known as a “pre-dawn dance". They eventually engage in a “true courtship dance" lasting about 8 hours, during which the male pumps water through the egg pouch on his trunk which expands and opens to display its emptiness. When the female’s eggs reach maturity, she and her mate let go of any anchors and snout-to-snout, drift upward out of the seagrass, often spiraling as they rise. The female inserts her ovipositor into the male’s brood pouch and deposits dozens to thousands of eggs. As the female releases her eggs, her body slims while his swells. Both animals then sink back into the seagrass and she swims away.


Gestation
The male releases his sperm directly into seawater where it fertilizes the eggs, which are then embedded in the pouch wall and become surrounded by a spongy tissue. The male supplies the eggs with prolactin, the same hormone responsible for milk production in pregnant mammals. The pouch provides oxygen as well as a controlled environment incubator. The eggs then hatch in the pouch where the salinity of the water is regulated; this prepares the newborns for life in the sea.
The number of young released by the male seahorse averages 100–200 for most species, but may be as low as 5 for the smaller species, or as high as 1,500. When the fry are ready to be born, the male expels them with muscular contractions. He typically gives birth at night and is ready for the next batch of eggs by morning when his mate returns. Like almost all other fish species, seahorses do not nurture their young after birth. Infants are susceptible to predators or ocean currents which wash them away from feeding grounds or into temperatures too extreme for their delicate bodies. Less than 0.5% of infants survive to adulthood, explaining why litters are so large. These survival rates are actually fairly high compared to other fish, because of their protected gestation, making the process worth the great cost to the father. The eggs of most other fish are abandoned immediately after fertilization.

Feeding habits
Seahorses feed on small crustaceans floating in the water or crawling on the bottom. With excellent camouflage and a lot of patience, seahorses ambush prey that float within striking range. Mysid shrimp and other small crustaceans are favorites, but some seahorses have been observed eating other kinds of invertebrates and even larval fish.
While many aquarium hobbyists keep seahorses as pets, seahorses collected from the wild tend to fare poorly in home aquaria. Many eat only live foods such as brine shrimp and are prone to stress, which damages their immune systems and makes them susceptible to disease.
In recent years, however, captive breeding has become more popular. Such seahorses survive better in captivity, and are less likely to carry diseases. They eat frozen mysidacea (crustaceans) that are readily available from aquarium stores, and do not experience the stress of moving out of the wild. Although captive-bred seahorses are more expensive, they take no toll on wild populations.

Use in Chinese medicine



Seahorse populations are thought to have been endangered in recent years by overfishing and habitat destruction. 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. Medicinal seahorses are not readily bred in captivity as they are susceptible to disease and it is believed that they have different medicinal properties from aquarium seahorses. Seahorses are also used as medicines by the Indonesians, the Central Filipinos, and many other ethnic groups around the world.

Threats & Future
Most seahorse species are data deficient. This means there is not enough information to make a proper assessment about their risk of extinction. Because seahorse population is unknown, there is a greater risk of losing more seahorses because of the lack of information about how many are dying each year, how many are being born, how many are used for souvenirs, etc. Seahorse habitats are in great danger though. Coral reefs and seagrass beds are deteriorating, meaning seahorses have fewer places to live. Also as stated above, seahorses are used to Chinese Medicine and as souvenirs, which definitely cuts their population down significantly each year.