Maned seahorse  (Hippocampus guttulatus)

The maned seahorse is classified as Data Deficient on the IUCN Red List (1) and listed on Appendix II of CITES (3).

The maned seahorse (Hippocampus guttulatus) is a particularly striking species of seahorse, named after the prominent fleshy spines that run down the back of the neck, giving the appearance of a ‘mane’ (4). The colour of the maned seahorse ranges from greenish-yellow to reddish brown, often mimicking the colour of the surrounding environment (4), providing this small fish with valuable camouflage. The body is also often patterned with various spots and blotches (2) (5). Like other seahorses, the maned seahorse has a long snout and a prehensile tail that can curl around to grip any object in the water (4) (6).

This eastern Atlantic species can be found in European waters from the Netherlands, south to Portugal and the Mediterranean. The maned seahorse may also occur in the Suez Canal (1).

The maned seahorse inhabits shallow waters, down to a depth of 12 metres, in areas of seaweed or seagrass (2) (5). It is thought to spend winter in rocky areas in deeper waters (2).

While information on the biology of the maned seahorse is lacking, it is likely to be similar to that of other seahorses (Hippocampus species). Seahorses are ambush predators that wait in the water until prey, such as a small crustacean, other invertebrate or tiny young fish, passes close by its mouth. With a rapid intake of water, the seahorse sucks the prey up into its long snout (7).

The most distinctive and arguably the most interesting feature of seahorse biology is the manner in which they reproduce. During mating, which in the maned seahorse takes place between March and October (2), the female deposits a clutch of eggs into a pouch in the male’s tail, where they are fertilised by the male. The male then seals the pouch shut, enclosing the embryos in a protective environment in which the developing seahorses are supplied with oxygen through a network of capillaries (7). After a gestation period of three to five weeks the male enters labour (2), which lasts for hours as the male actively forces the young out of the pouch. Immediately after birth, the young seahorses are independent and receive no further care from either parent (7). The maned seahorse has been reported to produce broods of up to 581 young (2).

This fascinating seahorse is caught both intentionally and accidentally in Portugal, where it is dried and sold for curios, and is also known to be captured incidentally in Italy, France, Spain and Croatia (1). The maned seahorse is also caught live for aquariums and the pet trade (2). While the extent to which this trade impacts populations of the maned seahorse is not known, such exploitation is likely to pose a threat (1). The maned seahorse’s preference for shallow habitats also makes it highly vulnerable to habitat degradation; shallow, coastal habitats are particularly susceptible to the negative impacts of human activities (1).

As with all Hippocampus species, the maned seahorse is listed on Appendix II of the Convention on International Trade in Endangered Species (CITES), meaning that any trade in this species should be carefully monitored (3). It has been recommended that further research into the biology, ecology, abundance and distribution of this cryptic species is required (1); this would enable its current status to be determined and further conservation measures to be implemented if necessary.

View information on this species at the UNEP World Conservation Monitoring Centre.

For further information on the conservation of seahorses see:

• The Seahorse Trust:
  http://www.theseahorsetrust.co.uk/
• Project Seahorse:
  http://seahorse.fisheries.ubc.ca/