Crowned seahorse (Hippocampus coronatus)

GenusHippocampus (1)
SizeMaximum height: 12.7 cm (2)

Classified as Data Deficient (DD) on the IUCN Red List 2006 (1), and listed on Appendix II of CITES (3).

This Japanese seahorse earns its common name for the tall, backward-curving crown on top of its head, which is coupled with rather unusual, irregular spines projecting out of the body (4). The skin is yellowish, marbled with dark brown, and black along the back. Like other seahorses, the head is held at right angles to the body, the eyes can move independently of each other, and the tail is prehensile. Instead of having scales, as most other fish do, seahorses have a layer of skin stretched over bony plates that are visible as rings passing around the trunk. Swimming is powered by the rapidly oscillating dorsal fin, and they steer using the fins on either side of the body (the pectoral fins) (2).

Endemic to Japanese waters in the northwest Pacific (5).

Found among Sargassum close to shore (2) (5).

Unusually, it is the male, and not the female, that becomes pregnant in seahorses (6). The breeding season of this species is June to July and there are reports that broods contain ‘several hundred’ young, although this may refer to H. sindonis, a similar species that has only recently been distinguished as a separate species (1) (2). Young look like miniature adult seahorses, are independent from birth, and receive no further parental care (6).

Very little is known about the total number of crowned seahorses, its population trends, or major threats. It has therefore been classified as Data Deficient on the IUCN Red List 2006. Trade surveys conducted by Project Seahorse between 2000 and 2001 indicate that trade in this species is relatively small. Furthermore, the crowned seahorse is not targeted by any fishery in Japanese waters, although it may be caught incidentally as bycatch (1).

All seahorses (Hippocampus spp.) are listed on Appendix II of CITES, effective as of May 2004, limiting and regulating their international trade (2). With such limited data available on this fascinating animal, there is an urgent need for further research to be conducted on its biology, ecology, habitat, abundance and distribution, before its status can be properly assessed and conservation measures implemented accordingly (1).

For more information on the crowned seahorse and other seahorses see:

Project Seahorse:

Authenticated (19/12/2006) by Sara Lourie, Project Seahorse/Redpath Museum, McGill University.

  1. IUCN Red List (December, 2009)