Hardwicke’s pipefish (Solegnathus hardwickii) belongs to the Syngnathidae family, which is named after the Greek wordsyngnathus meaning ‘fused jaw’ (2). The longest and thickest member of its family, Hardwicke’s pipehorse also has the highest number of body rings (3). Its body is almost entirely covered with rounded projections, or tubercles, and its back is flat or slightly curved. This species also has a short spine on the back of the snout (4).
The body of Hardwicke’s pipefish is yellowish-brown, with blackish edges on the ridges of its back and tail (3). It has dark but faint diagonal barring on the sides of its tube-like snout and across each eye, and dusky bars on the underside of the first half of the tail. Its fins are translucent (4), and its eyes are golden with black streaks (3).
Male Hardwicke’s pipefish have a ‘brood pouch’ situated on the tail which has five to eight brood compartments (4). The pear-shaped eggs laid by female Harwicke’s pipefish may be yellow, orange or amber in colour (1).
- Also known as
- pallid seahorse, pipehorse.
- Hippocampus hardwickii, Syngnathus hardwickii.
- Total length: 23.5 - 51 cm (1)
Hardwicke’s pipefish biology
There is currently very little information available on the life history of Harwicke’s pipefish. However, species within the Syngnathidae family are known to feed on crustaceans and it is therefore probable that this species has a similar diet (1). Members of this group feed using their tube-like snout to suck up prey through a small mouth (5).
Seahorses and pipefishes are unusual in that they both exhibit remarkable male parental care. In Harwicke’s pipefish the female lays pear-shaped eggs and transfers them to the male’s simple brood pouch using a specialised structure called an ovipositor (6). Within the brood pouch the eggs are surrounded by blood capillaries that give a ready supply of oxygen (1), and they are nourished and develop there until they are ready to hatch (6).
Hardwicke’s pipefish range
Hardwicke’s pipefish is known from the South China Sea northwards to southern Japan, and from the western Indian Ocean in Mauritius. This species is also found in northern and Western Australia (1).
Hardwicke’s pipefish habitat
Despite reliable indications that Hardwicke’s pipefish associates with certain habitat types such as deep water at the edge of coral reefs, these associations are unconfirmed at present. This species is mostly captured among trawled species which have been caught at depths of 12 to 100 metres, although it has also been collected in water as deep as 180 metres. In Australia, Hardwicke’s pipefish is reported as bycatch associated with sea fans, black corals, algae and sponges (1).
Hardwicke’s pipefish status
Hardwicke’s pipefish is classified as Data Deficient (DD) on the IUCN Red List (1).
Hardwicke’s pipefish threats
The most severe threat to species such as Hardwicke’s pipefish is commercial trawling. This species is caught unintentionally as bycatch in fisheries intended for prawn and scallop, and is often sold for use in traditional medicine (1). Pipefish are intentionally collected for their reported pharmaceutical value (1) (4), and to be sold as curios and food in Asian markets (7).
Hardwicke’s pipefish conservation
Australian pipefishes are protected in Australian Commonwealth waters. As Hardwicke’s pipefish is found in Australian waters it is also protected under this law. Additionally, pipehorses in Australia’s Commonwealth waters are ‘listed marine species’ and are protected under the Environment Protection and Biodiversity Conservation Act 1999. To take, trade, injure or kill any of these listed marine species is illegal, unless a permit is issued by the Minister of the Environment (1).
Hardwicke’s pipefish receives no specific protection in Indonesia or the Philippines, but all pipehorses are subject to the requirements of fisheries legislation in these areas (1).
Find out more
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- Simple plants that lack roots, stems and leaves but contain the green pigment chlorophyll. Most occur in marine and freshwater habitats.
- In the fishing industry, the part of the catch made up of non-target species.
- Diverse group of animals with jointed limbs and a hard external skeleton, characterised by the possession of two pairs of antennae, one pair of mandibles (mouthparts used for handling and processing food) and two pairs of maxillae (appendages used in eating, which are located behind the mandibles). Includes crabs, lobsters, shrimps, woodlice and barnacles.
- The egg-laying organ of a female insect, consisting of a tube-like structure at the end of the abdomen. In worker bees and non-reproductive female wasps, it is modified into a sting.
- Sea fan
- A type of coral that grows from a point of attachment and has a tree- or fan-like skeleton. Sea fans are mainly found in warmer seas.
- Tubercle (tubercles)
- A small, rounded, wart-like bump on the skin or on a bone.
IUCN Red List (February, 2013)
BBC Nature - Syngnathidae (February, 2013)
Kaup, J. (1856) Catalogue of Lophobranchiate Fish in the Collection of the British Museum. The British Museum, London.
Dawson, C. (1982) Synopsis of the Indo-Pacific Genus Solegnathus (Pisces: Syngnathidae). Japanese Journal of Ichthyology, 29(2): 139-161.
Guest, A. and Craig, J. (2011) Editorial: The biology of Syngnathidae: pipefishes, seadragons and seahorses. Journal of Fish Biology, 78: 1597-1602.
Wilson, A., Ahnesjo, I., Vincent, A. and Meyer, A. (2003) The dynamics of male brooding, mating patterns, and sex roles in pipefishes and seahorses (Family Syngnathidae). Evolution, 57(6): 1374-1386.
Carpenter, K. (2002) Syngnathidae. In: The Living Marine Resourcesof the Western Central Pacific. Volume 4: Bony Fishes Part 2 (Mugilidae to Carangidae). Food and Agriculture Organization of the United Nations, Rome. Available at: