Seahorses are an elusive species that turn divers giddy with excitement. But what is it about them that fascinates people so much?


It’s not a horse of course 


Seahorses are unusual little marine creatures that belong to the fish family “Syngnathidae”, which includes seahorses, pipefish, sea dragons and pipehorses. They occur throughout the oceans of the world (except in the coldest seas at both poles) and can be found living in a variety of habitats including seagrass meadows, coral reefs, sponge gardens, and even on artificial structures such as jetties.

All seahorses belong to the one genus, Hippocampus, derived from the Greek: “hippo” meaning horse, and “kampos” meaning sea monster. So the head of a horse on the body of a sea monster – the term Hippocampus couldn’t describe a seahorse more perfectly!


Falling in love 


Did you know that seahorses can mate for life? Throughout the year, and especially during the breeding season (which is generally over the summer months), a male and female seahorse will come together in the early morning light, and perform a ritual mating dance for several minutes to cement their bond. During the dance, both seahorses can change colour and they will curl their tails together, slowly turning as they perform their greeting dance. And if the time is right, at the completion of the dance, the female will transfer her eggs to the male.



Big-belly seahorse, Hippocampus abdominalis © Dr. Dave Harasti



Growing up


Birth: When seahorses are born, they are fully developed and look just like tiny adults. Depending on the species, babies can range in size from two to 10 millimetres.


Four months: Initially, they grow quite rapidly. In the White’s seahorse, it was found that a small eight-millimetre baby can grow to 80 millimetres and reach maturity in just four months: this is when it can be determined if the baby has grown into a male or female, through the presence or absence of a pouch.


Pelagic life: Depending on the species, some seahorses will have a pelagic stage where the young will drift in the open water or “raft” on flotsam such as sargassum seaweed.


Six months: Other species (like the White’s) have no pelagic stages and the babies will settle in the area where they were born and likely remain in the same location as they mature to adulthood. After six months, White’s are about 100 millimetres long and fully mature, ready to breed.


Six years: The life expectancy of seahorses in the wild varies considerably depending on the size of the species – larger seahorses will live longer. The White’s seahorse is known to live for up to six years in the wild, with the oldest known living wild seahorse being a large female appropriately named Grandma, which was seen on the same site for five years.


Read more: The Do’s And Don’ts of Diving with Seahorses 



The information here was taken from an article by Dave Harasti (a marine scientist for Fisheries NSW) in Asian Diver’s “The Big Blue Book” issue 2/2016. In order to read the full article, which includes detailed analysis, images and infographics, purchase the magazine at the shop or get the e-magazine. The issue itself is dedicated to seahorses (the theme of ADEX 2016) and includes stunning images, tips for divers, destinations where you can find seahorses, as well as input from conservationists about protecting this beautiful marine creature.

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