Seahorse, Hippocampus sp. (Distribution, biology and conservation) – Video

This video was taken in Monterey Aquarium, California, USA

Video ownership and review: Abdel Rahman El Gamal (Founder of the website and video channel)

Introduction: the name of seahorses is given to about 40 species of marine fish that occur worldwide. This group belongs to the family: Syngnathidae and the genus Hippocampus. The genus name comes from the Ancient Greek whereas Hippo means horse and Kampos means sea monster. The name in other Greek translation means bent horse. The size of this unique fish may reach up to 35 cm with an estimated lifespan of about 5 years.

Distribution range: Seahorses are mainly found in tropical and temperate waters throughout the world. Several seahorse species are found in Pacific waters from North America to South America as well as in the Atlantic. Seahorses also occur in Bahamas, some European waters and in the Mediterranean Sea. A given body of water may host seahorse species different from those in another water body.
Habitat: Typically Seahorses are found in shallow waters with abundant vegetation. They are well camouflaged among the relatively tall eelgrasses, seaweeds and coral branches.

Physical description: Seahorses are unique animals whether is their shape, behavior or reproduction. Even though, seahorses might not look like traditional fishes, they are true fishes of the class Actinopterygii (ray-finned fishes).
Seahorses are elongate with their bodies covered with bony rings and ridges. They have a flexible, well-defined neck. They swim upright. Because of their body shape, seahorses are poor swimmers and can easily die of exhaustion in unfavorable conditions. They are often found resting around stationary objects.
While seahorses have pectoral fins and a small dorsal fin, they do not have caudal fins. They have long snouts, which they use to suck up food, and eyes that can move independently of each other.

Feeding habits: They have small mouths located at the end of its tube-like snouts. Seahorses have no teeth and no stomach. They use their elongated snouts to suck in their food that drifts by. While the small shrimp-like crustacean, mysid is their most favorite food, Seahorses feed also on plankton, small crustaceans, and fish larvae which may float or crawl on the bottom within striking range. Their excellent camouflage helps catching their prey. Because of the make-up of their digestive system, eaten food passes through their digestive systems quickly, and hence they must eat almost constantly to stay alive.

Reproduction: In general, Seahorses are monogamy animals in which –with some exceptions- and depending on species, mating partners remain as such for life time or at least during the breeding season. Among the unique reproductive features, the male seahorse bears the unborn young till birth.
It is believed that the lengthy courtship that may last days helps seahorse partners to synchronize the timing for the deposit/receive of mature eggs which is done upon the insertion of female’s ovipositor into the male’s brood pouch which is located on their ventral, or front-facing, side. The number of deposited eggs could range from tens to several thousands. Afterwards, the female swim away while the male releases his sperm directly into seawater where it fertilizes the eggs. In the same time, 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.
Upon the completion of incubation which lasts 2-6 weeks depending on the species, eggs hatch and remain in the pouch for 2-4 weeks. During this period the newborns develop and get prepared for sea life. By the end of this phase, male seahorse gives birth to the tiny seahorses of about 1 cm long. The number of born depends on the species and could range from as low as 5 for the smaller species to as high as 1500. The mating could be repeated between the same couple throughout the breeding season. There is no parental care provided after birth. It is believed that less than 0.5% of born seahorses survive to adulthood.
Several species of sea horse are now bred in aquariums and hence reducing the pressure on wild-caught seahorse stocks.

Threats and conservation: It is believed that the information on seahorse population dynamics is not sufficient in general. However, loss of habitats, pollution, and over fishing must have negative impacts on seahorse populations. Harvesting of seahorse is mainly done for the trade of ornamental fish or for the use in Asian traditional medicine.
According to IUCN and CITES, many of sea horse species are either endangered or vulnerable and at a significant risk. That is why some countries have issued the policies to regulate and trade for endangered seahorse species.

References: Wikipedia, National Geographic, fun facts, Animals and Aquatic community

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