Hippocampus kuda

''Hippocampus kuda'' is a species of seahorse, also known as the common seahorse, estuary seahorse, yellow seahorse or spotted seahorse. The common name sea pony has been used for this species under its synonym ''Hippocampus fuscus''.

Physical description

The yellow seahorse is a small fish that can reach a length of 17–30 cm. The body is quite large, elongated, and has no spines, all bumps are rounded. The head is relatively large compared to the body. The snout is short and thick. The coronet is small and rises towards the rear, it can also sometimes have more or less long filaments. Some adults have a black line running through the dorsal fin in the direction of its width. The body coloration is often dark with a grainy texture but can also be yellow, cream, or reddish blotches and numerous small dark spots.

The seahorse possesses a tail that is used as a bending and grasping appendage. The seahorse is able to bend its tail ventrally due to its possession of body plates. The hypoxia muscle is responsible for bending the seahorse's tail. The plates send forces to the hypoxia muscles to ensure bending of the tail. These functions of the musculoskeletal system allow us to understand the anatomy of seahorses in further depth.

Distribution and habitat

The ''Hippocampus kuda'' inhabits waters from the Persian Gulf to Southeast Asia, Australia, Japan, and several Pacific islands including Hawaii, and is also found the eastern coast of Africa from Tanzania to South Africa, including the Indo-Pacific region ranging from the northwest Indian Ocean to the central areas of the Pacific Ocean. The majority of ''H. kuda'' populates the Chinese coast down to Australia.

''H. kuda'' inhabit estuaries, lagoons, harbors, littoral zones, and coastal seagrass beds, where they are found in shallow waters of up to fifty-five meters in depth. Their habitat regions can include (but are not limited to) tropical, saltwater, or marine regions.

Biological development and reproduction

Reproduction of the ''H. kuda'' is done primarily by the males. Eggs are fertilized by the male and are implanted in their pouches through an ovoviviparous process and it is the male who broods the eggs in its ventral brood pouch. There may be up to one-thousand eggs in a singular pouch, where the developmental process can last from twenty to twenty-eight days. Birth, however, depends largely on the monsoon patterns, lunar cycles, and water temperature. Males typically go into labor during a full moon, and after birth, the baby seahorses average a length of seven millimeters.

The mating system of the ''H. kuda'' is completely monogamous. The species engages in a unique courtship ritual before engaging in mating. The male will change its color patterns and dance around the female and while producing a clicking with the coronet. Eventually, the tails of the male and female intertwine and the female will place her eggs into the male's brooding pouch via the ovipositor.

Predation

''H. kuda'' can only eat living, moving prey, such as larval fishes and zooplankton. They suck their prey through their snouts since they are subpar swimmers. Although minuscule, ''H. kuda'' cannot avoid predation due to their inability to camouflage. Most predators of the ''H. kuda'' include crabs, rays, tuna, and sea turtles. Even humans are considered a large predator of the ''H. kuda'' largely because of their economic benefits. ''H. kuda'' is at the bottom of its ecosystem with its population feeding crustaceans and larger fish. ''H. kuda'' are considered omnivores of their food web.

Importance to humans

''H. kuda'' are extremely valuable to the traditional Chinese medicine trade. ''H. kuda'' has been said to regulate nervous, reproductive, endocrine, and immune systems. 25 million seahorses are used every year for medicinal purposes. The largest known exporters of ''H. kuda'' are Vietnam, India, the Philippines, and Thailand.

In the aquarium

''H. kuda'' is a popular species among aquarium keepers. Common seahorses have very small mouths, eating only small animals like brine shrimp and even newborn guppies. Seahorses need to eat approximately 4–5 times daily. Many aquarists who have kept ''H. kuda'' cultivate their own brine shrimp and rotifers. ''Daphnia'' is eaten when other foods are unavailable.Bailey, Mary; Gina Sandford. The Ultimate Encyclopedia of Aquarium Fish & Fish Care. p. 239.

Seahorses spend most of their time anchoring to coral reefs and branches with their tails because they are poor swimmers. They therefore need similar anchor points in the aquarium. Seahorses like a quiet tank, without large, belligerent fish, and a slow-moving current. Aquarists have found them to be generally accepting of tankmates like ''Synchiropus splendidus'' and other bottom-dwelling fishes.

Temperature, pH, and salinity

Common seahorses generally do best at a temperature of , optimally . They do not tolerate even spikes above well.
Their optimal pH range is around 8.1–8.4. The common seahorse can tolerate a range of salinity from 18 parts per thousand (ppt) to 36 ppt but salinity below about 25ppt should be promptly corrected. About 32 ppt is ideal.

Conservation status

The species is still commonly encountered (especially in Indonesia and New Guinea) but is currently classified as vulnerable by the IUCN, as populations face some threat from bycatch in the shrimp trawl fishery, targeted catch for the aquarium and traditional medicine trade, and habitat destruction, coupled with low fecundity due to the involved method of parental brood care. Internationally, it is also listed in Appendix II of the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES), which means that it is not necessarily threatened with extinction, but its trade must still be controlled in order to avoid utilization incompatible with their survival. Populations of the ''H. kuda'' have declined by 30% in the last few decades due to pollution, habitat destruction, and illegal trading in Chinese medicine.

References

External links

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Hippocampus kuda (Common seahorse)

{{Taxonbar, from=Q716470

kuda
Fish of the Pacific Ocean
Fish of Oceania
Fish of Southeast Asia
Fish of Hawaii
Vulnerable fauna of Asia
Vulnerable fauna of Oceania
Taxa named by Pieter Bleeker
Fish described in 1852
Taxonomy articles created by Polbot