Karen Boswarva looks at the reproductive life of one of the most remarkable – and delicate – fish in the sea
OCEANSCIENCE
Long-snouted seahorse Hippocampus guttulatus
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was captivated recently by a book eloquently written by Helen Scales, entitled Poseidon’ s Steed. Within it, Helen delves into the fascinating world of seahorses. It’ s a group of species I’ ve actually had very little interaction with since a university club dive trip to Lanzarote more than a decade ago. My memory of it remains vivid though, a seemingly uneventful twometre dive to find a 30cm piece of rope on a seabed of barren sand, armed only with a compass and the sheer stubbornness to find my prize. After almost giving up – success – it appeared out of the blue, bouncing back and forth like a crazed pendulum. It was the most exquisitely formed fish I’ d ever laid eyes on. Seahorses belong to a larger group of fish called the syngnathids( meaning fused jaw) which also includes all the pipefish, pipehorses, and seadragon species. There are currently 46 recognised species of seahorse( a number that keeps changing), all so closely related that they all belong to the same genus, Hippocampus.
Hippocampus comes from the Ancient Greek hippókampos, meaning hippo( horse) and kampos( sea monster). In mythology the hippocampus was a sea monster with the head of a horse and the tail of a fish. Makes you wonder what the ancients thought when they caught these un-fish like animals in their nets.
Seahorses are found throughout the globe in Southeast Asia, the eastern Atlantic and Americas at latitude 50 North to 50 South.
The joy of seahorses
Karen Boswarva looks at the reproductive life of one of the most remarkable – and delicate – fish in the sea
Hippocampus hippocampus
They tend to be found in shallow seas of seagrass, mangrove, estuarine, algal, and coral habitats. We even get two species in the UK, the short snouted seahorse( Hippocampus hippocampus) and the spiny seahorse( Hippocampus guttulatus).
Ask a well-informed diver to name a fun seahorse fact and they’ ll likely tell you that the males carry the babies in their pouch. They wouldn’ t be wrong. However, seahorse reproduction is an altogether unique and rather fascinating process, whereby the male seahorses don’ t just carry the young, they actually become pregnant.
Most fish species( except some sharks) lay eggs that hatch outside the mother, a process called ovipary. True pregnancy is a term often reserved for mammalian species, where
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