Jayakar’s seahorse (Hippocampus jayakari)

Kingdom	Animalia
Phylum	Chordata
Class	Actinopterygii
Order	Syngnathiformes
Family	Syngnathidae
Genus	Hippocampus (1)
Size	Maximum height: 14 cm (2)

Jayakar’s seahorse is classified as Data Deficient (DD) on the IUCN Red List (1) and listed on Appendix II of CITES (3).

With their horse-like head, upright posture, locomotive dorsal fin, and prehensile tail, the seahorses (Hippocampus spp.) are some of the most peculiar fish in the sea (4) (5). Like all Hippocampus species, the skin of Jayakar’s seahorse (Hippocampus jayakari) is stretched over bony plates, visible as distinct rings on its trunk and tail (2) (5). The colour of its body ranges from pale cream to beige, but is often patterned with conspicuous white spots. In addition, long and sharp, dark-tipped spines protrude over much of its body (2).

Jayakar’s seahorse has been confirmed in the coastal waters of Israel, Oman and Pakistan, but its distribution is suspected to also include Bahrain, Djibouti, Egypt, Eritrea, Iran, Kuwait, Qatar, Saudi Arabia, Somalia, Sudan, United Arab Emirates and Yemen (1) (2).

Although Jayakar’s seahorse has been reported at depths of up to 20 metres, it is commonly caught at a depth of two to three metres, amongst seagrass beds, soft-bottom sponges and algae-covered rubble (1) (2) (5).

Little is known about the specific biology of Jayakar’s seahorse, but seahorses in general exhibit a number of shared traits. The most extraordinary of these is the most extreme form of male parental care yet to be discovered (6) (7). To reproduce, the female seahorse deposits eggs into a brood pouch at the base of the male’s tail. The male then fertilises the eggs and carries them for the duration of their development. The brood pouch acts in much the same way as a female mammal’s womb, providing nutrients and oxygen to the developing embryos, whilst expelling unwanted waste products (7). At the end of gestation, which can last from four to six weeks, the male goes into several hours of labour, during which time it pumps the young seahorses from its brood pouch (6) (7). The newborns are completely independent and receive no further parental care (7).

Despite their gentle appearance, seahorses tend to be voracious predators, ingesting just about anything moving that is small enough to fit into their mouths. This usually includes small crustaceans, fish fry and other invertebrates (7).

Although Jayakar’s seahorse may be susceptible to population declines as a consequence of habitat degradation and being caught as bycatch, almost nothing is known about the status of its population. Consequently, this seahorse is currently classified as Data Deficient on the IUCN Red List (1). Fortunately, it has never been reported in international trade (1) (2).

Given the lack of information on the status and vulnerability of the Jayakar’s seahorse, further research on the biology, ecology, abundance and distribution of this species is vital to inform conservation measures.

For further information on the conservation of seahorses see:

• Project Seahorse:
  http://seahorse.fisheries.ubc.ca

This information is awaiting authentication by a species expert, and will be updated as soon as possible. If you are able to help please contact:
arkive@wildscreen.org.uk

• Algae: simple plants that lack roots, stems and leaves but contain the green pigment chlorophyll. Most occur in marine and freshwater habitats.
• Bycatch: in the fishing industry, the part of the catch made up of non-target species.
• Crustaceans: diverse group of arthropods (a phylum of animals with jointed limbs and a hard chitinous exoskeleton) characterised by the possession of two pairs of antennae, one pair of mandibles (parts of the mouthparts used for handling and processing food) and two pairs of maxillae (appendages used in eating, which are located behind the mandibles). Includes crabs, lobsters, shrimps, slaters, woodlice and barnacles.
• Dorsal fin: the unpaired fin found on the back of the body of fish, or the raised structure on the back of most cetaceans.
• Gestation: the state of being pregnant; the period from conception to birth.
• Invertebrates: animals with no backbone, such as insects, crustaceans, worms, molluscs, spiders, cnidarians (jellyfish, corals, sea anemones) and echinoderms.
• Prehensile: capable of grasping.

1. IUCN Red List (October, 2008)
   http://www.iucnredlist.org/
2. Lourie, S.A., Foster, S.J., Cooper, E.W.T. and Vincent, A.C.J.  (2004) A Guide to the Identification of Seahorses. Project Seahorse and TRAFFIC North America. University of British Columbia and World Wildlife Fund, Washington D.C. Available at:
   http://seahorse.fisheries.ubc.ca/Seahorses/IDguide.html
3. CITES (October, 2008)
   http://www.cites.org
4. Campbell, A. and Dawes, J. (2004) Encyclopedia of Underwater Life. Oxford University Press, Oxford.
5. Foster, S.J. and Vincent, A.C.J. (2004) Life history and ecology of seahorses: implications for conservation and management. Journal of Fish Biology, 65: 1-61.
6. Burnie, D. (2001) Animal. Dorling Kindersley, London.
7. Project Seahorse - Biology of seahorses (February, 2009)
   http://seahorse.fisheries.ubc.ca/Seahorses/SHBiology.html