Solegnathus hardwickii 

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Language: English

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Taxonomy [top]

Kingdom Phylum Class Order Family
Animalia Chordata Actinopterygii Syngnathiformes Syngnathidae

Scientific Name: Solegnathus hardwickii (Gray, 1830)
Common Name(s):
English Hardwicke's Pipehorse, Hardwicke's Pipefish, Pallid Pipehorse, Pallid Seahorse, Pipehorse
Solegnathus polyprion Bleeker, 1853
Solenognathus asperrimus Philippi, 1896
Syngnathus hardwickii Gray, 1830
Taxonomic Source(s): Dawson, C.E. 1985. Indo-Pacific Pipefishes (Red Sea to the Americas). The Gulf Coast Research Laboratory Ocean Springs, Mississippi, USA.
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: 2017
Date Assessed: 2016-05-17
Assessor(s): Pollom, R.
Reviewer(s): Ralph, G.
Contributor(s): Morgan, S.K., Pogonoski, J., Pollard, D.A. & Paxton, J.R.
Solegnathus hardwickii is a marine shelf pipehorse that inhabits areas with hard substrates, coral, algae, and sponges off the coasts of eastern and northwestern Australia, the South China Sea and adjacent countries, and Japan. The species is often caught as bycatch in trawl fisheries and extensively traded for traditional medicine use. Although little is known about habitat use or population size, trawl bycatch data indicate significant and consistent declining trends between 1998 and 2010. A simultaneous decline in effort has also occcurred, and it's not clear to what extent these catch declines represent population declines. Further research is needed in order to determine population size and trends in abundance, and therefore this species is listed as Data Deficient.

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.
Previously published Red List assessments:

Geographic Range [top]

Range Description:Solegnathus hardwickii is a coastal species that occurs in waters from Kyushu, Japan to New South Wales and Western Australia (Dawson 1985).

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.
Countries occurrence:
Australia (Northern Territory, Queensland, Western Australia); China; Japan; Malaysia; Philippines; Taiwan, Province of China (Taiwan, Province of China (main island)); Thailand; Viet Nam
FAO Marine Fishing Areas:
Indian Ocean – western; Indian Ocean – eastern; Pacific – western central; Pacific – northwest
Additional data:
Continuing decline in area of occupancy (AOO):Unknown
Extreme fluctuations in area of occupancy (AOO):UnknownEstimated extent of occurrence (EOO) - km2:
Continuing decline in extent of occurrence (EOO):UnknownExtreme fluctuations in extent of occurrence (EOO):Unknown
Continuing decline in number of locations:Unknown
Extreme fluctuations in the number of locations:Unknown
Lower depth limit (metres):100
Upper depth limit (metres):12
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 this 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.
Data from the Australian east coast trawl fishery indicates that catch is declining. Although fluctuations in bycatch levels would be expected based on the patchiness of the species, there is a clear and significant (82 and 74% on the GBR and east coast, respectively) declining trend between 2003 and 2010 (Coles et al. 2007, Queensland Government 2012).
Current Population Trend:Decreasing
Additional data:
Continuing decline of mature individuals:Unknown
Extreme fluctuations:UnknownPopulation severely fragmented:Unknown
Continuing decline in subpopulations:Unknown
Extreme fluctuations in subpopulations:UnknownAll individuals in one subpopulation:Unknown

Habitat and Ecology [top]

Habitat and Ecology: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.

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 510 cm (Connolly et al. 2001). 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 such as harpacticoid copepods, mysids, and gammarid shrimps (Teixeira and Musick 1995, Teixeira and Musick 2001, Woods 2002, Kendrick and Hyndes 2005).

Solegnathus hardwickii attains a total length of at least 510 mm (Connolly et al. 2001).
Continuing decline in area, extent and/or quality of habitat:Unknown
Movement patterns:Unknown

Use and Trade [top]

Use and Trade: Solegnathus hardwickii is caught as bycatch in trawl fisheries and extensively traded for use in traditional medicine (Martin-Smith et al. 2003, Martin-Smith and Vincent 2006). See threats for further details.

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 (2006) 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 2006). 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: 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.
The species is not mentioned in any international legislation or trade regulations. A large portion of its habitat falls within the Great Barrier Reef Marine Park.
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.

Citation: Pollom, R. 2017. Solegnathus hardwickii. The IUCN Red List of Threatened Species 2017: e.T20315A67623640. . Downloaded on 24 September 2018.
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