Solegnathus hardwickii


Taxonomy [top]

Kingdom Phylum Class Order Family

Scientific Name: Solegnathus hardwickii
Species Authority: (Gray, 1830)
Common Name/s:
English Hardwicke's Pipefish, Pallid Seahorse
Taxonomic Notes: Preliminary investigations into the taxonomy of this species suggest that the true Solegnathus hardwickii is restricted to the South China Sea and Japan (the type specimen is from China). It has been suggested that there may be two undescribed species, one distributed on the east coast and the other on the west coast of Australia (Kuiter 2000). Until the taxonomy is resolved, we have treated Solegnathus hardwickii as one species which occurs in all the areas mentioned below.

Assessment Information [top]

Red List Category & Criteria: Data Deficient ver 3.1
Year Published: 2006
Date Assessed: 2006-01-31
Assessor/s: Morgan, S.K., Pogonoski, J.J., Pollard, D.A. & Paxton, J.R.
Reviewer/s: Morgan, S.K. & Martin-Smith, K. (Syngnathid Red Listing Authority)
Information presently available on which to assess S. hardwickii includes limited catch data from the Queensland trawl fishery, Australian trade records and minimal biological data. Consideration was given to listing the species as Vulnerable or Near Threatened under Criteria A (Reduction in Population Size) and/or B (Geographic Range). None of the information, however, provides compelling evidence for listing based on trends in catch, area of occurrence or area of occupancy, and this is why the species remains in the category DD. This is due to poor and/or unreliable data, rather than information that points towards population stability.

Australian export data, showing take in commercial trawls along the Queensland coastline, indicate that there may be the potential for bycatch to threaten populations. Between February 1998 and May 2000, a combined total of 2,384 kg of dried Solegnathus dunckeri and S. hardwickii were taken in trawls by commercial fishers along the Queensland coastline. Considering that dried pipehorses probably weigh less than 50 g, at least 20,000 individuals would be expected to occur in 1 t (1,000 kg). A total of only 31 kg of dried S. dunckeri and S. hardwickii were landed from Jan. to Sept. 2000. These figures for the 2000 calendar year are of potential concern, considering the high 1998 (2,175 kg) and 1999 (209 kg) export statistics for the abovementioned species combined (Pogonoski et al. 2002). While this represents declines of 99% and 85% between 1998 and 2000 and 1999 and 2000 respectively (a period of time S. dunckeri and S. hardwickii remained constant in catch across years, making it difficult to interpret species-specific effects. Furthermore, there is presently no way of contextualizing bycatch and export volumes (of bycatch sold into the traditional medicine trade) relative to in situ population abundances.

The extent of occurrence for this species is presently much greater than 20,000 km², however there remains taxonomic confusion where S. hardwickii is concerned. Animals from Asian and Australian waters are considered one species, where they may not be; it has also been proposed that there may be two species within Australia. Taxonomic research is therefore necessary to resolve the biological separation or integrity of what is presently referred to as S. hardwickii. Once the species’ taxomony has been fully resolved, the resultant species and/or populations should be re-evaluated.

There is reliable anecdotal and scientific (Connolly et al. 2001) evidence suggesting that S. hardwickii associates with particular types of habitat. However, until these associations are understood, and ocean coastlines are mapped at high benthic resolution, it will not be possible to differentiate between the species’ area of occurrence and its area of occupancy.

Accurate distribution and depth data are required to identify key habitats. These data may be logistically challenging to obtain given that a large proportion of the species’ population may inhabit waters deeper than those that can be visited on SCUBA for monitoring. Some species-specific data on distribution and biology could be obtained by monitoring trawl catch on the southern Queensland and northern New South Wales coastline. In Queensland, a Species of Conservation Interest (SOCI) logbook programme is in progress and a ship-board observer programme is scheduled to start in the near future (K. Martin-Smith, pers. comm). There does not appear to be the option to return trawled specimens which probably do not survive if released due to prolapse (K. Graham, pers. comm.).

The designation of suitable non-trawl protected areas with bottom structure suspected to support pipehorses in the northern New South Wales and southern Queensland region would be a suitable precautionary approach, until the impact of trawling both in terms of direct capture as well as the indirect effects of habitat damage can be established.
1996 Vulnerable

Geographic Range [top]

Range Description:South China Sea north to southern Japan, south to northern Australia. Solegnathus hardwickii is known from tropical and subtropical Australia, the South China Sea and Japan (Dawson 1985) as well as from the western Indian Ocean in Mauritius, although doubts have been expressed about whether all specimens represent a single species or a species complex (Kuiter 2000: see below). The type specimen for the species comes from China. In Australia it occurs in Western Australia, the Northern Territory and in Queensland southwards to the NSW-Queensland borders (Paxton et al. 1989). Landings surveys confirm that S. hardwickii has been landed as far south as Ballina (NSW) (Bowles 2001). Russell (1983) reported it as rare in the Capricorn-Bunker section of the Great Barrier Reef Marine Park. In Western Australian waters it is has been found north of Onslow (21°38’S) (Allen and Swainston 1988).

Museum Records (Australia)
29 specimens (Standard Length 235–440 mm), collected from depths of 20–180 m, ranging in geographical distribution from off Cairns (16°55’S), Qld, southwards to the Tweed River mouth (28°10’S), NSW on the east coast of Australia and on the west coast from north-east of Monte Bello Islands (20°03’S), WA northwards to north-east of Cape Lambert (19°15’S), WA. There are also two records from the Arafura Sea (08°53’S, 135°12’E and 09°42’S, 133°58’E), NT and one record from near Kempsey (31°05’S), New South Wales, but the Kempsey specimen has been destroyed, so the identification cannot be verified. Specimens were collected between 1894 and 1997. Additionally, 40 specimens (381–510 mm total length) are housed at Griffith University, Queensland that were collected in October 2000 in a depth range of 16–89 m between Shoalwater Bay (22°32’S) and Hervey Bay (24°55’S), Qld as part of a scientific trawling survey.

Australian Marine Protected Areas in Which the Species Occurs:
Great Barrier Reef Marine Park, Qld.
This species possibly occurs in the following MPAs:
Bowling Green Bay Fish Habitat Area A; Repulse Fish Habitat Area B; Mackay-Capricorn Marine Park, Qld; Broad Sound Fish Habitat Area, Qld; Bustard Fish Habitat Area A; Hervey Bay Marine Park, Qld.

Follow the link below for map of the known range of S. hardwickii.
For further information about this species, see 20315_Solegnathus_hardwickii.pdf.
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Australia (Northern Territory, Queensland, Western Australia); China; Indonesia; Japan; Malaysia; Mauritius; Philippines; Thailand; Viet Nam
FAO Marine Fishing Areas:
Indian Ocean – eastern; Indian Ocean – western; Pacific – northwest; Pacific – western central
Range Map:Click here to open the map viewer and explore range.

Population [top]

Population: A scientific trawling survey carried out in October 1999 between Hervey Bay and Shoalwater Bay in Queensland provides the first density estimates for this species (Connolly et al. 2001). In the abovementioned study, density estimates for Solegnathus hardwickii range from 0 to 128 individuals per km² (mean 3.2 km-2 ± 12.9 sd). Within this study region populations were very patchily distributed and the sex ratio was even (Connolly et al. 2001). No information is available from any other populations in the species’ range.
Population Trend: Unknown

Habitat and Ecology [top]

Habitat and Ecology: Habitat:
Solegnathus hardwickii is mostly known from trawled specimens captured from 12 m to 100 m depth (Dawson 1985), though it has been collected in depths of up to 180 m. Fishers in south-eastern Australia report catching S. hardwickii in association with gorgonians, black corals, algae or sponges (Bowles 2001, Bowles and Martin-Smith, unpublished data). Positive correlations with the carbonate fraction of the seabed were found during trawl surveys in 1999 and it has been suggested that S. hardwickii is associated with deep edges of coral reefs (Connolly et al. 2001). Further in situ research is needed to confirm both general habitat use and specific habitat critical for particular life history stages (e.g., nursery areas, spawning grounds, etc.) for Solegnathus hardwickii. Connolly et al. (2001) suggest that habitat structure or other environmental variables may be important to the survival of this species.

Behaviour and Biology:
Solegnatus hardwickii is ovoviviparous and males carry the eggs embedded in spongy tissue under the tail (Paxton et al. 1989). Pear-shaped eggs that may be yellow, orange or amber are embedded in the epithelial tissue, and the surrounding capillaries supply oxygen to the embryos (Lourie et al. 1999). Pregnant males have been found at total length as small as 29.6 cm (Dawson 1985), and the species grows to a recorded maximum total length of 50 cm (Dawson 1985). The number of egg scars (a proxy for egg number) ranged from 19 to 207 with a mean of 117 ± 64 sd for trawled specimens from southern Qld (Connolly et al. 2001). Using modal progression analysis Connolly et al. (2001) calculated a growth rate of 0.25–0.33 mm d-1 for females and 0.29–0.50 mm d-1 for males over the size range 30–45 cm. Limited otolith work estimated age at 3–5 years for these trawled individuals (Connolly et al. 2001). Pipehorses probably rely on camouflage to avoid predators. The diet is unknown, but like other species in the family, it probably feeds on small crustaceans (Teixeira and Musick 1995, Teixeira and Musick 2001, Woods 2002).

Solegnathus hardwickii attains a total length of at least 510 mm (Connolly et al. 2001).
Systems: Marine

Threats [top]

Major Threat(s): The main threat to this species is commercial trawling, where S. hardwickii is bycatch in prawn and scallop fisheries. A secondary and related concern is the demand for pipehorses in traditional medicine. Animals taken in trawls as bycatch are sold to Asian markets as medicinal ingredients. It is not known whether availability creates demand, but using fairly conservative estimates of the total retail trade in Hong Kong, Martin-Smith et al. (2003) concluded that that all Australian exports of pipehoses, could be consumed in Hong Kong and still leave a shortfall.

Between February 1998 and May 2000, a combined total of 2,380 kg of dried Solegnathus dunckeri and Solegnathus hardwickii were taken in trawls by commercial fishers in the Queensland East Coast Otter Trawl Fishery. Exports from Australia generally consist of approximately 40% Duncker’s Pipehorse and 60% Hardwick’s Pipehorse (Connolly et al. 2001); major destinations include Hong Kong (62%), Taiwan (31%) and China (6%) (Martin-Smith and Vincent, in press). These trades could potentially threaten the populations of these two species, particularly if current levels of exploitation continue. Data are not presently available to examine to what degree bycatch of pipehorses may subsidize the prawn fishery, but income generated from the sale of pipehorses is likely to be minimal relative to sales from the valuable primary target.

Research by Martin-Smith and Vincent (in prep) also points to the fact that illegal or un-reported exports may misrepresent true trade volumes, and hence do not accurately reflect potential threats. Comparison between Australian export data and import data for pipehorses into Hong Kong and Taiwan indicates large discrepancies (up to five-fold) (Martin-Smith and Vincent in prep). This suggests that Australian exports may be significantly under-reported, where pipehorses are likely to have been recorded as seahorses through some combination of misidentification, translation and errors in data coding. Support for this view is provided by trade estimates derived from interviews with pipefish processors in Australia: these match well with import figures from Hong Kong and Taiwan (Connolly et al. 2001).

No life history information presently exists for this species, where its inherent biology (reproductive rate, brood size, growth rate, etc.) may confer poor resilience to exploitation. This is thought to be the case for some other species of syngnathids (Foster and Vincent 2004).

Conservation Actions [top]

Conservation Actions: Precis (from Pogonoski et al. 2002):
1. All syngnathids are subject to the export controls of the Commonwealth Wildlife Protection (Regulation of Exports and Imports) Act 1982 from 1 January 1998.
2. All syngnathids and solenostomids are listed as marine species under s248 of the EPBC Act 1999.
3. Australian Society for Fish Biology: Data Deficient.

More information (from Martin Smith et al., 2003):
All Australian pipehorses have been protected in Australian Commonwealth (federal) waters (greater than three nautical miles from the coast) since the beginning of 1998. As most pipehorses are caught in Commonwealth waters they are protected under the Environment Protection and Biodiversity Conservation Act 1999 wherein they are ‘listed marine species’. It is an offence to take, trade, injure or kill listed marine species except under permits issued by the Minister of the Environment. Such permits for exports of syngnathids are issued subject to a management plan, which must be approved by the executive agency, Environment Australia (within the Department of Environment and Heritage). Legal protection is variable for pipehorses caught in Australian State waters (less than three nautical miles from the coast), ranging from full to no protection. In other range nations such as Indonesia and the Philippines, pipehorses are subject to the provisions of fisheries legislation but receive no specific protection.

Bibliography [top]

Allen, G.R. and Swainston, R. 1988. The Marine Fishes of North-Western Australia. Western Australian Museum, Perth, Australia.

Baillie, J. and Groombridge, B. 1996. 1996 IUCN Red List of Threatened Animals. International Union for Conservation of Nature, Gland, Switzerland.

Bensky, D. and Gamble, A. 1993. Herbs that tonify the Yang. In: Chinese Herbal Medicine - Materia Medica. Revised Edition. pp. 354–356. Eastland Press, Inc. Seattle, Washington, USA

Bowles, D.R.J. 2001. The nature of the bycatch fishery of Solegnathus spp. (Pipehorses) in NSW demersal trawl fisheries. Report to NSW Fisheries Scientific Committee.

Connolly, R.M., Cronin, E.R. and Thomas, B.E. 2001. Trawl bycatch of syngnathids in Queensland: catch rates, distribution and population biology of Solegnathus pipehorses (seadragons). School of Environmental and Applied Sciences, Griffith University, Gold Coast.

Dawson, C.E. 1985. Indo-Pacific pipefishes (Red Sea to the Americas). The Gulf Coast Research Laboratory Ocean Springs, Mississippi, USA.

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.

Froese, R. and Pauly, D. (eds). 2005. FishBase version (11/2005). World Wide Web electronic publication. Search FishBase.

IUCN. 2006. 2006 IUCN Red List of Threatened Species. Downloaded on 04 May 2006.

Kuiter, R.H. 2000a. Seahorses, Pipefishes and their Relatives. A Comprehensive Guide to Syngnathiformes. TMC Publishing, Chorleywood, UK.

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

Martin-Smith, K.M. and Vincent, A.C.J. 2006. Exploitation and trade of Australian seahorses and their relatives (syngnathids). Oryx (in press).

Martin-Smith, K.M., Lam, T.F.-N. and Lee, S.K.-H. 2003. Trade in Pipehorses Solegnathus spp. for Traditional Medicine in Hong Kong. Traffic Bulletin 19: 139–148.

Paxton, J.R., Hoese, D.F., Allen, G.R. and Hanley, J.E. 1989. Pisces. Petromyzontidae to Carangidae. Australian Government Publishing Service, Canberra, Australia.

Pogonoski, J.J., Pollard, D.A. and Paxton, J.R. 2002. Conservation overview and action plan for Australian threatened and potentially threatened marine and estuarine fishes. Environment Australia, Canberra, Australia.

Russell, B.C. 1983. Annotated Checklist of the Coral Reef Fishes in the Capricorn-Bunker Group, Great Barrier Reef. Great Barrier Reef Marine Park Authority, Townsville. 184pp.

Teixeira, R.L. and Musick, J.A. 1995. Trophic ecology of two congeneric pipefishes (Syngnathidae) of the lower York River, Virginia. Environmental Biology of Fishes. 43: 295–309.

Teixeira, R.L. and Musick, J.A. 2001. Reproduction and food habits of the lined seahorse, Hippocampus erectus (Teleostei: Syngnathidae) of Chesapeake Bay, Virginia. Revista Brasileira de Biologia 61: 79–90.

Vincent, A.C.J. 1996. The International Trade in Seahorses. TRAFFIC International, Cambridge, UK.

Woods, C.M.C. 2002. Natural diet of the seahorse Hippocampus abdominalis. New Zealand Journal of Marine and Freshwater Research 36(4): 655–660.

Citation: Morgan, S.K., Pogonoski, J.J., Pollard, D.A. & Paxton, J.R. 2006. Solegnathus hardwickii. In: IUCN 2013. IUCN Red List of Threatened Species. Version 2013.2. <>. Downloaded on 19 April 2014.
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