Cambodia's many species of Seahorse was one of the main reason for the development of Marine Conservation Cambodia.

The Seahorse itself is a wonderful creature that has for centuries been believed to hold magical and medicinal qualities (these myths have led to Seahorse populations around the world being  targeted). A seahorse has a horse-like head, bony plated body and prehensile tail. Today, there are about 32 known species of Seahorses. Seahorses make up the genus Hippocampus, which is from the family Syngnathidae, which otherwise contains the Pipefish, Pipehorses and Seadragons. As to date in Cambodia about 7 different species og Seahorse have been identified by Marine Conservation Cambodia so far.

Most Seahorses in Cambodia are found in coastal waters, typically at depths of 1–30 meters, occurring in relatively sheltered environments among sea-grasses, kelp beds, rocky reefs, mangroves, Sandy bottoms and coral reefs. Unfortunately these are some of the most vulnerable of Cambodia's marine environments, highly susceptible to disturbance caused by human activities.

Many life history and biological factors enhance Seahorses vulnerability to disturbance and exploitation and reduce their potential for recruitment and recovery. These factors include: low mobility, limited home ranges and high site fidelity, low fecundity, live brooding and lengthy paternal care, mate fidelity and late maturity.

Biology of seahorses

Seahorses have heads at right angles to the body and fully prehensile tails, which wrap around sea-grass stems, corals, sticks, or any other suitable natural or artificial object. These traits, along with a pouch for the young and eyes that swivel independently of each other, lend to the unique nature of these fish. Instead of the scales found on most fish, seahorses have a thin layer of skin stretched over a series of bony plates visible as rings around the trunk. These rings are useful in identifying species, as are the cheek spines and coronet (a crown-like group of spines on the top of the head). In addition to the spines, some species also have bony bumps or skin filaments protruding from these bony rings.

Like other fish, they breathe through gills, extracting oxygen from the water that passes over them. Unlike other fish, however, the gills are small and compacted, almost “grape-like” in structure. Seahorses swim using the propulsive force of a quickly oscillating dorsal fin, and use the pectoral fins on either side of the body for steering and stability. 

Seahorses are masters of camouflage, changing colour and growing skin filaments to blend in with their surroundings. They are more adapted to maneuverability than speed, and therefore rely primarily on camouflage to avoid detection from predators. Short-term colour changes may also occur during courtship displays and daily greetings. Male and female seahorses can be told apart by the presence of a brood pouch on the male.

Seahorses have no stomach or teeth. They suck in prey through a tubular snout and pass it through an inefficient digestive system. Seahorses are voracious predators, relying entirely on live, moving food. They will sit for prey to come close enough and then sucking them rapidly from the water with their long snouts. Their eyes move independently of each other, maximizing their search areas. They will ingest anything that is small enough to fit into their mouths -- mostly small crustacea such as amphipods, but also fish fry and other invertebrates.

Reproduction and Lifespan

The male seahorse, rather than the female, becomes pregnant. This unusual mode of reproduction is the most extreme form of male parental care yet discovered.

Natural lifespans for seahorses are virtually unknown. Most estimates come from laboratory or aquarium observations. Known lifespans for seahorse species range from about one year in the smaller species to an average of three to five years for the larger species.  

Sexual maturity in males is usually determined by the presence of a brood pouch. Male seahorses are able to become pregnant any time during the breeding season, which varies with species, and is most likely dependant on temperature of the water. Other factors that may affect the timing of the breeding season are monsoon patterns and the lunar cycle.

Most species of seahorses are monogamous, forming pair bonds that last the entire breeding season (and perhaps even last over several breeding seasons), although some species may not be pair-bonded. Pair bonds are reinforced by daily greetings in which the female and male change colour and promenade and pirouette together. This dance lasts several minutes, and then they separate for the rest of the day. The greetings occur throughout the male pregnancy, and are even thought to ensure that the male and female are ready to re-mate at the same time. Once the male has given birth and it is time to re-mate, sometimes only hours later, this greeting is extended into a courtship that, for one species, lasts up to nine hours. 

The female inserts her ovipositor into the male’s brood pouch, where she deposits her eggs, which the male fertilizes. The fertilized eggs then embed in the pouch wall and become enveloped with tissues. The pouch acts like the womb of a female mammal, complete with a placental fluid that bathes the eggs, and provides nutrients and oxygen to the developing embryos while removing waste products. The pouch fluid is altered during pregnancy from being similar to body fluids to being more like the surrounding seawater. This helps reduce the stress of the offspring at birth.

Pregnancy lasts between two and four weeks, the length decreasing with increasing temperature. At the end of gestation the male goes into labour (usually at night), pumping and thrusting for hours to release his brood. Young are miniature adult seahorses, independent from birth, and receive no further parental care. Newborns of most species measure 7-12 mm. The number of young released averages about 100-200 for most species, but can be a low as five for the smaller species, or as high as 1,500.

Interesting Seahorse Links

Project Seahorse

Seahorse.org

ISeahorses

Kingdom of Seahorses