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Western Spiny Seahorse Hippocampus angustus Günther, 1870
[CAAB 37 282077]

Distribution Map see an interactive map here (new window)

The Western Spiny Seahorse is found only in Western Australian waters between Shark Bay and the Dampier Archipelago.

Distribution, ecology and habitat:

Endemic to tropical waters of Western Australia, from Shark Bay, north to the Dampier Archipelago; benthic in inshore algal reefs from about 10 to more than 30 m.

Size:

Height to 160 mm.

Food and feeding:

Unknown. Like other seahorses, this species presumably feeds by sucking small crustaceans and other planktonic organisms into its mouth.

Reproduction and early life history:

Reproduction: Sexes separate, reproduction a form of viviparity or ovoviviparity, whereby the males give birth to tiny independent young. The female uses an ovipositor to transfer her eggs into an elaborate enclosed pouch under the abdomen of the male. The male not only fertilizes the eggs inside the pouch and provides physical protection for the developing embryos, he also osmoregulates and aerates the embryos and may provide some nourishment until the offfspring are born.
Eggs: Not described.
Larvae: Not described.

Characteristics:

Meristics: D 17-19 (usually 18); P 15-19 (usually 16-17); trunk rings 11; tail rings 32-35 (usually 33-34); subdorsal rings 2 + 1.
Head and body: Body slender; head angled downward from longitudinal axis of trunk; snout long, length 2.2 (2.0-2.5) in head length.
Spines and tubercles: Spines well-developed, tips blunt or sharp, usually low in neck region; cheek spines sharp, double; double spine below eye; eye spine sharp, prominent; subdorsal spines 3/0,1,0.
Coronet: Coronet moderately high with 5 well-developed sharp divergent spines.
Fins: Dorsal fin short-based.
Lateral line: A series of small pores, more or less distinct, extending to 20^th tail ring, pores difficult to detect posteriorly.

Colour:

Colour overall grey to brownish, often with a combination of white, yellow, orange or brown fine scribbly or net-like markings on the head and body; 5-6 distinctive dark irregular stripes across the snout; dorsal fin with a thin dusky marginal line. In preservative - pale brown with thin dusky bars on snout and scribble markings on head and body.

Similar species:

The Western Spiny Seahorse has been confused with Hippocampus histrix, H. spinosissimus and H. multispinus.

Fisheries:

Aalthough H. angustus is taken as bycatch in commercial trawls, there is no known trade in this species for the aquarium or Traditional Medicine industries.

Conservation Status:

International: Listed under Appendix II of the Convention on the International Trade in Endangered Species of Wild Flora and Fauna (CITES).
Listed as Data Deficient on the 2008 IUCN Red List of Threatened species.
Australian Government Legislation: Marine Listed under the Federal Environment Protection and Biodiversity Conservation Act 1999 (EPBC Act 1999)

Remarks:

H. angustus was until relatively recently thought to have a distribution extending south to Cockburn Sound.

Other common names:

Western Australian Seahorse, Narrow-bellied Seahorse, Slender Seahorse

Original citation:

Hippocampus angustus Günther 1870, Cat. Fish. Brit. Mus. 8: 200, Freycinet's Harbour (Shark Bay, Western Australia).

Etymology:

Hippocampus is from the Greek, ippos = horse and kampe = curvature. The specific name angustus is from the Latin meaning narrow, presumably in reference to the narrow body of this species.

References:

Allen G.R. & R. Swainston. 1995. The marine fishes of north-western Australia: a field guide for anglers and divers. Western Australian Museum, Perth, Western Australia, 201 pp.

Foster, S.J. & A.C.J. Vincent. 2004. Life history and ecology of seahorses: implications for conservation and management. J. Fish Biol. 65: 1-61.

Günther, A. 1870. Catalogue of the fishes in the British Museum. 8: 1-549.

Hoese, D.F., D.J. Bray, J.R. Paxton & G.R. Allen. 2006. Fishes. In Beesley, P.L. & A. Wells. (eds.) Zoological catalogue of Australia. Volume 35. ABRS & CSIRO Publishing: Australia, 2178 pp.

Kuiter, R.H. 2000. Seahorses, Pipefishes and their Relatives. Chorleywood, UK: TMC Publishing, 240 pp.

Kuiter, R.H. 2001. Revision of the Australian Seahorse of the genus Hippocampus (Syngnathiformes: Syngnathidae) with descriptions of nine new species. Rec. Aust. Mus. 53: 293-340.

Project Seahorse 2002. Hippocampus angustus. In: IUCN 2008. 2008 IUCN Red List of Threatened Species. <http://www.iucnredlist.org/>. Downloaded on 09 April 2009.

Jones, A.G., C. Kvarnemo, G.I. Moore, L.W. Simmons & J.C. Avise. 1998. Microsatellite evidence for monogamy and sex-biased recombination in the Western Australian seahorse Hippocampus angustus. Molecular Ecology 7(11): 1497-1505.

Lourie, S.A., A.C.J. Vincent & H.J. Hall. 1999. Seahorses: an identification guide to the world's species and their conservation. Project Seahorse, London. 214 pp.

Neira F.J., A.G. Miskiewicz & T. Trnski. 1998. Larvae of temperate Australian fishes: laboratory guide for larval fish identification. University of Western Australia press, Nedlands, Western Australia.

Pogonoski, J.J., D.A. Pollard & J.R. Paxton. 2002. Conservation Overview and Action Plan for Australian Threatened and Potentially Threatened Marine and Estuarine Fishes. Canberra, Environment Australia, 375 pp.