New Holland seahorse

New Holland seahorse
Conservation status
	; Endangered (IUCN 3.1)
	CITES Appendix II (CITES)
Scientific classification
Kingdom:	Animalia
Phylum:	Chordata
Class:	Actinopterygii
Order:	Syngnathiformes
Family:	Syngnathidae
Genus:	Hippocampus
Species:	H. whitei
Binomial name
	Hippocampus whitei; Bleeker, 1855
Synonyms
	Hippocampus novaehollandae Steindachner, 1866; Hippocampus procerus Kuiter, 2001;

Last updated January 04, 2023

Hippocampus whitei, commonly known as White's seahorse, New Holland seahorse, or Sydney seahorse, is a species of marine fish of the family Syngnathidae. It is thought to be endemic to the Southwest Pacific, from Sydney, New South Wales and southern Queensland (Australia) to the Solomon Islands.^[1]^[3] It lives in shallow, inshore habitats, both natural and anthropogenic. This species is ovoviviparous, with males brooding eggs in a brood pouch before giving birth to live young.^[3]

Identification

H. whitei is a small fish, reaching a maximum size of 13 centimetres (5.1 in). Distinctive characteristics include a narrow head, moderate to high coronet, a long snout (about half of overall head length), moderately sized spines above the eyes, and low single or double cheek spines. Further spines on the body can be quite variable, ranging from low and rounded to moderately developed and sharp.^[4]

Individuals of this species are generally pale to dark brown or black, although some are entirely yellow. Often, they have pale, saddle-like markings at the first, fourth and eighth trunk rings, and on tail rings with enlarged spines. The underside of the snout typically has fine bars and dusky lines which get broader near the eyes. The nasal spine and surrounding area is pale.^[4]

Habitat

H. whitei inhabits shallow, weedy inshore areas, usually at depths of 1–25 metres (3.3–82.0 ft).^[3] Its natural habitats include Zostera seagrass beds, sponges, kelp holdfasts, macroalgae, and corals, but it can also be found under jetties and on other anthropogenic structures, such as shark nets.^[3]^[4]^[1] Evidence from Port Stephens indicates that juveniles prefer gorgonian habitats (Euplexaura sp.), while adults prefer sponges and soft coral habitats.^[1] This species is known to show a preference for more complex habitats, likely because their camouflage is more effective in these environments, making avoiding predators easier. Additionally, prey of H. whitei are significantly more abundant in complex habitats, increasing food availability.^[5] Observed increases in the use of artificial habitats by H. whitei are likely driven by the continued loss of their natural habitats.^[1]

Ecology

Feeding and predation

This carnivorous species feeds on small crustaceans such as harpacticoid, caprellid and cyclopoid copepods, gammarid amphipods, caridean shrimp, and mysids, similar to other seahorse species.^[1]

Predators of H. whitei include invertebrates, fishes, sea turtles, waterbirds and marine mammals. Most of the species’ predators are considered generalist feeders, suggesting that H. whitei are not targeted as prey.^[6]

Reproduction

H. whitei is an ovoviviparous species, with females using an ovipositor to transfer eggs into a male's brood pouch, where they are fertilized and protected until the male gives birth to live young.^[1] Males may brood 100-250 embryos at a time, and after a three-week gestation period, give birth to about 150 young. Males brood several times a season. Newborns are about 8.5 millimetres (0.33 in) long and morphologically similar to adults.^[4] They grow rapidly and are able to reproduce early. This species displays strong site fidelity and seasonal monogamous mating.^[1]^[7]

Population

Population information for H. whitei is available from two estuaries in Australia: Port Stephens and Port Jackson. Surveys in Port Stephens indicate a steep decline in H. whitei abundance, with two site surveys (the Pipeline and Seahorse Gardens) estimating 95-98% population decline from 2006-2015. This trend has been correlated with significant declines in preferred seahorse habitat.^[1] Population surveys in Port Jackson also indicate a decline, with a site survey (the protective swimming enclosure of Manly Harbour) estimating 40% population decline from 2008-2015. Based on the available survey data, it is expected that overall population declines of 50-70% have occurred.^[1]

Threats

The major threat experienced by H. whitei is habitat loss. This species occurs along some of the most highly populated estuaries in Australia, in which habitats tend to be the most impacted by coastal development, pollution, destructive boat anchoring and sedimentation. Impacts are likely amplified by the species’ site fidelity and specific habitat preferences.^[1]

Since this species is protected in Australia, there has been no reported legal trade of them in the last five years. Small numbers caught in bycatch may be illegally traded, but this is not thought to pose a significant conservation threat.^[1]

Conservation

H. whitei is protected under the New South Wales Fisheries Management Act (1999), and all Hippocampus species are listed under Appendix II of the Convention on International Trade in Endangered Species (CITES), which regulates the legal import and export of seahorses.^[1]

Related Research Articles

A seahorse is any of 46 species of small marine fish in the genus Hippocampus. "Hippocampus" comes from the Ancient Greek hippókampos (ἱππόκαμπος), itself from híppos (ἵππος) meaning "horse" and kámpos (κάμπος) meaning "sea monster" or "sea animal". Having a head and neck suggestive of a horse, seahorses also feature segmented bony armour, an upright posture and a curled prehensile tail. Along with the pipefishes and seadragons they form the family Syngnathidae.

The pygmy seahorses comprise several species of tiny seahorse in the syngnathid family or Syngnathidae. Family Syngnathidae is part of order Syngnathiformes, which contains fishes with fused jaws that suck food into tubular mouths. They are found in Southeast Asia in the Coral Triangle area. They are some of the smallest seahorse species in the world, typically measuring less than 2 centimetres (0.79 in) in height.

Hippocampus angustus, commonly known as the narrow-bellied seahorse, western Australian seahorse, or western spiny seahorse, is a species of marine fish of the family Syngnathidae. It is found in waters off of Australia, from Perth to Hervey Bay, and the southern portion of Papua New Guinea in the Torres Strait. It lives over soft-bottom substrates, adjacent to coral reefs, and on soft corals at depths of 3–63 metres (9.8–206.7 ft). It is expected to feed on small crustaceans, similar to other seahorses. This species is ovoviviparous, with males carrying eggs in a brood pouch before giving birth to live young. This type of seahorse is monogamous in its mating patterns. The males only fertilize one female's eggs for the mating season because of the population distribution. While some seahorses can be polygamous because they are denser in population, this type of seahorse is more sparsely distributed and the cost of reproduction is high. Therefore, the risk to reproduce due to predatory and distributary factors limits this breed to one mate, often finding the same mate season after season.

Barbour's seahorse is a species of fish of the family Syngnathidae.

The knobby seahorse, also known as the short-headed seahorse or short-snouted seahorse, is a species of marine fish of the family Syngnathidae. It inhabits coastal waters in southwestern and southeastern Australia, from Gregory to Bremer Bay, and from Denial Bay to Newcastle.

The giraffe seahorse is a species of fish of the family Syngnathidae. It is found in coastal waters off of the south and east coasts of Africa, from South Africa to Tanzania, and possibly north to Kenya. It lives in estuarine seagrass beds, algae beds, and shallow reefs to depths of 45 metres (148 ft), where it can grow to lengths of 10 centimetres (3.9 in). It is expected to feed on small crustaceans, similar to other seahorses. This species is ovoviviparous, with males carrying eggs in a brood pouch before giving birth to live young. Individuals are sexually mature at around 6.5 centimetres (2.6 in). Major threats to this species could be habitat loss, through coastal development and pollution, and overexploitation through bycatch. Some other threats include human use by drying out the seahorse for traditional medicine or as a curio.

Hippocampus fisheri, commonly known as Fisher's seahorse, or the Hawaiian seahorse, is a species of fish of the family Syngnathidae. It is known from the Hawaiian Islands, although previous misidentifications indicated species occurrences in Australia and New Caledonia. Habitat preferences are unknown, but it has been found far away from shore and at depths greater than 100 metres (330 ft). Feeding habits are also unknown, but individuals are expected to feed on small crustaceans similar to other seahorses. Hippocampus fisheri is one out of the three species of Hippocampus genus found in the Hawaiian islands. They are also expected to be ovoviviparous, with males carrying eggs in a brood pouch before giving birth to live young. Individuals can grow to lengths of 8 centimetres (3.1 in). The specific name and the common name honour "Walter V. Fisher” of Stanford University. There was a Walter Kenrick Fisher who was Jordan and Evermann’s colleague at Stanford and the “V” is assumed to be a typo.

<span class="mw-page-title-main">Long-snouted seahorse</span> Species of fish

Hippocampus guttulatus, commonly known as the long-snouted seahorse and in Great Britain as the spiny seahorse, is a marine fish belonging to the family Syngnathidae, native from the northeast Atlantic, including the Mediterranean.

Hippocampus kuda is a species of seahorse, also known as the common seahorse, estuary seahorse, yellow seahorse or spotted seahorse. The common name sea pony has been used for this species under its synonym Hippocampus fuscus.

<span class="mw-page-title-main">Japanese seahorse</span> Species of fish

The Japanese seahorse or lemur-tail seahorse is a species of fish in the family Syngnathidae. The Japanese seahorse reaches a maximum length of 8.0 cm, is usually dark brown and has a relatively long tail, a ridgelike coronet and flattened spines. Many seahorse species look similar, so in addition to any distinguishing features, individual specimens are identified using a series of specific measurements and counts of anatomical features such as spines and tail rings.

The hedgehog seahorse is a species of fish of the family Syngnathidae. It inhabits coastal waters from India and Sri Lanka to Taiwan and northern Australia. It is threatened by overfishing, as both targeted catch and bycatch. This species is ovoviviparous, with males carrying eggs in a brood pouch before giving birth to live young.

The false-eye seahorse, or flatface seahorse is a species of marine fish of the family Syngnathidae. It is endemic to Australia, from Shark Bay to Broome, where it is found in intertidal rockpools, shallow algae and weedy or rubble reef habitats. It is expected to feed on harpacticoid, calanoid, and cyclopoid copepods, caridean and gammaridean shrimps, and mysids, similar to other seahorses. This species is ovoviviparous, with males brooding eggs in a brood pouch before giving birth to live young.

The zebra seahorse is a species of fish in the family Syngnathidae. It is endemic to northern Australia.

The short-snouted seahorse is a species of seahorse in the family Syngnathidae. It was endemic to the Mediterranean Sea and parts of the North Atlantic, particularly around Italy and the Canary Islands. In 2007, colonies of the species were discovered in the River Thames around London and Southend-on-Sea.

The spiny seahorse, also referred to as the thorny seahorse, is a small marine fish in the family Syngnathidae, native to the Indo-Pacific area. It is classified as a Vulnerable species by the IUCN.

Coleman's pygmy seahorse is a species of fish of the family Syngnathidae. It is found off of the coast of Lord Howe Island, Australia, although unconfirmed occurrences have been reported from Milne Bay and the Ryukyu Islands. It lives in coarse sand and Zostera and Halophila sea grasses at depths around 5 metres (16 ft). It is expected to feed on small crustaceans, similar to other seahorses. Ovoviviparous reproduction is also expected, with males brooding eggs in a pouch before giving birth to live young.

Hippocampus debelius, commonly known as the softcoral seahorse, is a species of marine fish of the family Syngnathidae. It is known from only two specimens collected from the Gulf of Suez in the Red Sea, at depths of 15–30 metres (49–98 ft). Individuals were found associated with soft corals. Although little is known of this species, it is expected to feed on crustaceans, similar to other seahorses. It is also expected to be ovoviviparous, with males carrying eggs in a brood pouch before giving birth to live young.

The Patagonian seahorse is a species of marine fish of the family Syngnathidae. It inhabits coastal waters from northeastern Brazil to Chubut, Argentina. It generally is found at shallow depths attached to natural or artificial substrates. This species is ovoviviparous, with males brooding eggs in a brood pouch before giving birth to live young.

Hippocampus dahli is a fish species of the family Syngnathidae. It is endemic to the Australian northeastern coast, from Darwin to Brisbane, where it inhabits estuarine channels and rubble or soft substrates to depths of 21 metres (69 ft). Little is known of its feeding habits, but it is likely to feed on small crustaceans such as copepods, amphipods, and gammarid, caprellid, and caridean shrimps, similar to other seahorses. This species is ovoviviparous, with males carrying eggs in a brood pouch before giving birth to live young. This species is not listed in FishBase and many authorities treat it as a synonym of Hippocampus trimaculatus.

<i>Hippichthys penicillus</i> Species of fish

The beady pipefish is a species of pipefish of the family Syngnathidae. It is found in the Indo-West Pacific, from the western Persian Gulf, to the north central Indian Ocean, to Japan and Australia. It lives in the lower parts of streams and rivers, estuarine habitats such as seagrass beds and mangroves, and shallow inshore habitats, where it can grow to lengths of 16–18 centimetres (6.3–7.1 in). It is expected to feed on small crustaceans, similar to other pipefish. This species is ovoviviparous, with males carrying eggs in a brood pouch before giving birth to live young. Average brood size is 177.

References

1 2 3 4 5 6 7 8 9 10 11 12 13 14 Harasti, D.; Pollom, R. (2017). "Hippocampus whitei". IUCN Red List of Threatened Species . 2017: e.T10088A46721312. doi: 10.2305/IUCN.UK.2017-3.RLTS.T10088A46721312.en . Retrieved 15 November 2021.
↑ "Appendices | CITES". cites.org. Retrieved 2022-01-14.
1 2 3 4 Lourie, S.A., A.C.J. Vincent and H.J. Hall, 1999. Seahorses: an identification guide to the world's species and their conservation. Project Seahorse, London. p. 214
1 2 3 4 Dianne J. Bray & Vanessa J. Thompson, Hippocampus whitei in Fishes of Australia, accessed 03 Feb 2018, http://fishesofaustralia.net.au/home/species/1538
↑ Harasti, D., Martin-Smith, K. and Gladstone, W. 2014a. Ontogenetic and sex-based differences in habitat preferences and site fidelity of White's seahorse Hippocampus whitei. Journal of Fish Biology 85(5): 1413-1428.
↑ Kleiber, D., Blight, L. K., Caldwell, I. R. & Vincent, A. C. J. (2011). The importance of seahorses and pipefishes in the diet of marine animals. Reviews in Fish Biology and Fisheries 21, 205–223.
↑ Vincent, Amanda C. J.; Sadler, Laila M. (1995-01-01). "Faithful pair bonds in wild seahorses, Hippocampus whitei". Animal Behaviour. 50 (6): 1557–1569. doi:10.1016/0003-3472(95)80011-5. ISSN 0003-3472. S2CID 53192875.