Jayakar's Seahorse

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).

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.

With their horse-like head, upright posture, locomotive dorsal fin, and prehensile tail, the seahorses (Hippocampus sp.) are some of the most peculiar fish in the sea (4) (5). Like all Hippocampus species, the skin of Jayakar's seahorse 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).

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).

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).

Classified as Data Deficient (DD) on the IUCN Red List (1) and listed on Appendix II of CITES (3).

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).

Description: (based on 8 specimens): Adult height: 11.0-13.0cm. Rings: 11+38-39. Snout length: 2.1 (1.9-2.4) in head length. Dorsal fin rays: 18-19 covering 2+1 rings. Pectoral fin rays: 17-18. Coronet: low-medium with four very long sharp spines. Spines: very long and sharp; no spines on alternate tail rings. Other distinctive characters: double cheek spine (usually); double spine below eye; very long, sharp spine in front of coronet and above eye. Color pattern: pale cream or beige colored; often with a pattern of large white spots on body and face; spines with a broad dark band near tip; dark mid-ventral line.

Male carries the eggs in a brood pouch (Ref. 205).

Dorsal spines (total): 0; Dorsal soft rays (total): 1819

Also found in rocks and gravel and among sponges (Ref. 52034).

Found in seagrass beds, e.g. Halophila spp. Ovoviviparous (Ref. 205). The male carries the eggs in a brood pouch which is found under the tail (Ref. 205).

Jayakar's seahorse (Hippocampus jayakari) is a species of coastal fish of the family Syngnathidae. It is found in the Western Indian Ocean, from the Red and Arabian seas to the central coast of Pakistan. It lives in seagrass beds (such as Halophila spp.), algae, soft-bottom substrates, sponges, and rocky habitats, where it can grow to lengths of 14 centimetres (5.5 in). It can inhabit depths to 20 metres (66 ft), though it is more commonly found at 2–3 metres (6.6–9.8 ft). It is expected to feed on small crustaceans, similar to other seahorses. This species is ovoviviparous, with males carrying eggs in a brood pouch before giving birth to live young. Individuals reach sexual maturity at 11 centimetres (4.3 in). The specific name and the common name honours the Indian physician, linguist and ichthyologist Dr. Surgeon-Major Atmaram Sadashiv "Muscati" Jayakar (1844-1911).