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White's Seahorse Hippocampus whitei Bleeker, 1855
[CAAB 37 282027]

Distribution Map see an interactive map here (new window)

White's Seahorse is particularly common in shallow weedy areas in estuaries, bays and harbours in Sydney and Newcastle, attached to seagrass, sponges and kelp holdfasts.

Distribution, ecology and habitat:

Endemic temperate Australian species restricted to New South Wales; benthic, inhabiting shallow inshore areas in estuaries, harbours and bays in rocky reefs, sponge, seagrass habitats and under piers and jetties to 25 m.

Size:

Height to about 150 mm, commonly to 200 mm TL.

Food and feeding:

Diurnal feeders that suck up small crustaceans and passing zooplankton.

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. Behavioural studies have shown that male and female H. whitei form monogamous pair bonds during the breeding season which may last for several months from spring through to autumn, although breeding may occur throughout the year. Males have several broods during this time and often mate again within several days of giving birth at night. Following a gestation period of about 3 weeks, up to 150 independent young area born. Larger females produce more eggs.
Eggs: Egg diameter 1.8 mm.
Larvae: Morphologically similar to adults at birth; no pelagic phase, juveniles approximately 8.5 mm at birth.

Characteristics:

Meristics: D 16-17 (usually 17); A 4; P 15-17 (usually 16); trunk rings 11; tail rings 33-34; subdorsal rings 2 + 1.
Head and body: Head length about 90% of trunk length; snout length almost half head length; trunk length about ¹/₃ height; tail length about ²/₃ height.
Spines and tubercles: Subdorsal rings 3/0,1,0. Spine above eye of moderate size; nape spine small; shoulder-ring spines of moderate size in 3 locations, one near each end of pectoral-fin base but none at gill-opening, lowermost spine double with sub-equal spines; lateral head spine low; body tubercles of small to moderate size along dorsal and lateral ridges, some enlarged and pointed, especially on 8^th trunk ring, below dorsal fin and on following part of superior tail ridges; neck-ridge spines absent.
Coronet: Coronet moderate to tall in height, angled back, spines small and blunt in young, further reduced in large adults, arranged in five-point star at apex, with additional 2 or more small spines anteriorly on base.

Colour:

In life, overall pale to dark brown and almost black, with fine pale spots or striations; sometimes entirely yellow; often saddle-like markings at 1^st, 4^th and 8^th trunk rings, and on tail rings where spines are enlarged; snout finely barred with dusky lines dorsally, lines broader near eyes; nasal spine and adjacent area pale. In preservative - brown with blackish-brown scribbles and blotches.

Similar species:

H. whitei has been misidentified as  H. tristis, H. procerus and H.breviceps. H. whitei is most similar to H. procerus, differing in lower meristics, lower coronet and in generally being less spiny. H. tristis and H.breviceps both differ in having the upper shoulder-ring spine near the gill-opening rather than the pectoral-fin base.

Fisheries:

H. whitei may be trawled and discarded as bycatch in the southeast trawl fishery. The species is also collected for the aquarium trade and captive-bred individuals are sold on the domestic market.

Conservation Status:

International: Listed under Appendix II of the Convention on the International Trade in Endangered Species of Wild Flora and Fauna (CITES). As a result, the species is subject to the Convention. http://www.cites.org/.
Listed as Data Deficient on the 2007 IUCN Red List of Threatened species. http://www.iucnredlist.org/search/details.php/10088/summ
Australian legislation: Marine Listed under the Federal Environment Protection and Biodiversity Conservation Act 1999 (EPBC Act 1999). http://www.environment.gov.au/epbc/species/marine.html

Remarks:

Studies have shown that male and female H. whitei form monogamous pair bonds at least for the duration of the breeding season lasting for several months during  spring, summer and autumn. Individual H. whitei live in small home ranges which overlap extensively with those of their partners, as well as overlapping with non-partners. While the male is ‘pregnant', partners greet each other each morning and the female performs a greeting ritual. Males may have up to seven broods during the breeding season and may mate again the following day after giving birth. Courtship behaviour may last up to 9 hours.

Other common names:

Common Sea-horse, Whites Seahorse, New Holland Seahorse, Sydney Seahorse.

Original citation:

Hippocampus whitei Bleeker 1855, Verh. Akad. Amsterdam 2: 17, Sydney district, NSW.

Etymology:

From the Greek ippos = horse and kampe = curvature. The specific name whitei is after John White, surgeon-general of the First Fleet and author of Journal of a Voyage to New South Wales 1789, in which a portrait of H. whitei is published.

References:

Bleeker, P. 1855. Over eenige visschen van van Diemensland. Verh. Akad. Amsterdam 2: 1-30 + 31, 1 pl.

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. 1993. Coastal fishes of South-Eastern Australia. Crawford House Press,  Bathurst, NSW, Australia.

Kuiter, R.H. 1997. Guide to the sea fishes of Australia. New Holland Press, Sydney, Australia.

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

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, UK. 214 pp.

Martin-Smith, K.M. & A.C.J. Vincent. 2006. Exploitation and trade of Australian seahorses, pipehorses, sea dragons and pipefishes (Family Syngnathidae). Oryx, 40(2): 141-151.

Neira F.J., Miskiewicz A.G. & 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.

Vincent, A.C.J., K.L. Evans & A.D. Marsden. 2005. Home range behaviour of the monogamous Australian seahorse, Hippocampus whitei. Environmental Biology of Fishes 72(1): 1-12.

Vincent, A.C.J. & B.G. Giles. 2003. Correlates of reproductive success in a wild population of Hippocampus whitei. J. Fish Biol. 63: 344-355.

Vincent, A.C.J., A.D. Marsden, K.L. Evans & L.M. Sadler. 2004. Temporal and spatial opportunities for polygamy in a monogamous seahorse, Hippocampus whitei. Behaviour 141: 141-156.

Vincent, A.C.J. & R.M. Sadler. 1995. Faithful pair bonds in wild seahorses, Hippocampus whitei. Anim. Behav. 50: 1557-1569.

Whitley G.P. 1931 New names for Australian fishes. Aust. Zool. 6(4): 310-334

Whitley G. & J. Allan. 1958. The sea-horse and its relatives. The Griffin Press, Adelaide, Australia.

Wilson, A.B, I. Ahnesjo, A.C.J. Vincent & A. Meyer. 2003. The dynamics of male brooding, mating patterns, and sex roles in pipefishes and seahorses (family syngnathidae). Evolution 57(6): 1374-1386.