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88. A tiny Réunion Seahorse (Hippocampus borboniensis) in the middle of a sandy area


The Réunion Seahorse (Hippocampus borboniensis) is known to occur in the southwestern Indian Ocean along the African coast from Tanzania in the north to KwaZulu Natal in South Africa, Madagascar, and oceanic locations such as the Seychelles and the Mascareignes islands with La Réunion, Mauritius, and maybe even in Rodrigues.

The Réunion Seahorse can be found as shallow as 5m/15ft and as deep as 60m/200ft. It prefers sandy or seagrass areas and is not found on coral reefs.

Genetic research suggests that it may be part of the Hippocampus kuda complex, but some ichthyologists believe that Hippocampus borboniensis is just a synonym of Hippocampus kuda (Estuarine Seahorse). Others state that it is a different species endemic to the waters of the southwestern Indian Ocean and distinguished by a distinctive pattern, a more upright and distinctive coronet (the bump on top of the seahorse’s head), and a more slender head and body that generally occurs in adult specimens. Adults may occasionally have orange or yellow spots on their bodies.

The Réunion Seahorse can reach a length of up to 14cm/5.5 inches and feeds on a variety of zooplankton, copepods, amphipods, small shrimps, and other small crustaceans.


Miss-dropped we ended up away from the reef on a big wasteland with good visibility but nothing to see at first sight. Knowing that these sandy areas hold many secrets and small treasures, we decided to pry around. Suddenly my buddy spotted a tiny seahorse attached to a little oasis of bushy twigs in the middle of a sandy desert. This little gem seemed just like us completely lost. This dwarf-sized horse lookalike was only 3cm/1.2inch, and it was the very first one we had encountered in Mauritian waters.

Sometimes it pays off for underwater videographers and photographers to explore beyond the known sites. Sand flats often accommodate a treasure trove of little critters. Diving in these wasteland areas, where you need to look out for the strange and the unusual, is often referred to as “muck diving.” Usually, the best muck dive sites are quite shallow and often located in the vicinity of river mouths and inside small bays or enclosed estuaries. Muck diving is often very rewarding for underwater videographers and photographers. Because they are often located in shallow waters, allowing one to dive longer on a single scuba dive tank.

Seahorses tend not to cooperate with underwater photographers and videographers, often showing their backside to the observer. A simple but effective trick is to position your buddy on the other side of the seahorse so that it will show its side to the camera. If you stay quiet and still long enough, the seahorse may resume its normal behaviour, which is often the more interesting feature of the animal to capture on underwater video.

Unfortunately, our cylinders were close to 50bar/750psi when we discovered this little seahorse. By the time we had taken several shots, it was time to ascend to shallower waters, and we were unable to observe its normal behaviour.

More on this topic:

For more information about the Estuarine Seahorse please go to vlog post 62 or click this link: https://www.beyondscuba.com/post/an-estuary-or-common-seahorse-hippocampus-kuda

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