The Cape seahorse or Knysna seahorse (Hippocampus capensis) is a species of fish in the Syngnathidae family. It is endemic to South Africa. It lives in the Keurbooms River in Plettenberg Bay throughout the Knysna Lagoon and up to Swartvlei in Sedgefield. The limited range of this seahorse (the smallest-known of any seahorse) puts it at great risk of extinction. It feeds on a variety of zooplankton. Recent surveys by the ORCA Foundation in Plettenberg Bay have shown that the population in Plettenberg Bay has diminished from floods in 2007 and the more recent floods in 2011.
The Knysna seahorse is a small, delicate creature from 5 to 11 centimetres long. It is a mottled greenish brown colour, sometimes with scattered dark spots and possesses the characteristic seahorse shape. The body is encased in a series of bony rings, the snout is relatively short and the neck arches in a smooth curve without a crown. The tail is muscular and is used to grasp a mate during courtship or to anchor the fish to the substrate.
Seahorses have a remarkable method of reproduction; the female transfers her eggs into the male's pouch during mating. The eggs are fertilised within the pouch and embryos develop, embedded in the tissue lining the pouch wall of the 'pregnant' male. For the Knysna seahorse, the gestation period is around 2 - 3 weeks after which time the male ejects his offspring which are then extremely vulnerable, receiving no further parental care.
Seahorses have no teeth and no stomach. They lurk among the vegetation using camouflage to ambush small prey items which they then swallow whole. They are not particularly mobile creatures, being propelled forward only by movements of their dorsal fin.
This article incorporates text from the ARKive fact-file "Cape seahorse" under the Creative Commons Attribution-ShareAlike 3.0 Unported License and the GFDL.