New Holland seahorse

{{Short description|Species of fish}} {{Speciesbox | name = New Holland seahorse | image = Hippocampus whitei 1.jpg | status = EN | status_system = IUCN3.1 | status_ref = <ref name="iucn status 15 November 2021">{{cite iucn |author=Harasti, D. |author2=Pollom, R. |date=2017 |title=''Hippocampus whitei'' |volume=2017 |article-number=e.T10088A46721312 |doi=10.2305/IUCN.UK.2017-3.RLTS.T10088A46721312.en |access-date=15 November 2021}}</ref> | status2 = CITES_A2 | status2_system = CITES | status2_ref = <ref>{{Cite web|title=Appendices {{!}} CITES|url=https://cites.org/eng/app/appendices.php|access-date=2022-01-14|website=cites.org}}</ref> | taxon = Hippocampus whitei | authority = Bleeker, 1855 | synonyms = {{species list|Hippocampus novaehollandae|Steindachner, 1866|Hippocampus procerus|Kuiter, 2001}} | synonyms_ref = <ref name="iucn status 15 November 2021" /> }} '''''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.<ref name="iucn status 15 November 2021" /><ref name=fb>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</ref> 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.<ref name=fb/>

==Identification==

''H. whitei'' is a small fish, reaching a maximum size of {{convert|13|cm|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.<ref name=foa>Dianne J. Bray & Vanessa J. Thompson, Hippocampus whitei in Fishes of Australia, accessed 03 Feb 2018, http://fishesofaustralia.net.au/home/species/1538</ref>

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.<ref name=foa/>

==Habitat==

''H. whitei'' inhabits shallow, weedy inshore areas, usually at depths of {{convert|1-25|m|ft}}.<ref name=fb/> 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.<ref name=fb/><ref name=foa/><ref name="iucn status 15 November 2021" /> Evidence from Port Stephens indicates that juveniles prefer gorgonian habitats (''Euplexaura'' sp.), while adults prefer ''sponges'' and ''soft coral'' habitats.<ref name="iucn status 15 November 2021" /> 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.<ref>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.</ref> Observed increases in the use of artificial habitats by ''H. whitei'' are likely driven by the continued loss of their natural habitats.<ref name="iucn status 15 November 2021" />

==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.<ref name="iucn status 15 November 2021" />

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.<ref>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.</ref>

===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.<ref name="iucn status 15 November 2021" /> 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 {{convert|8.5|mm|in}} long and morphologically similar to adults.<ref name=foa/> They grow rapidly and are able to reproduce early. This species displays strong site fidelity and seasonal monogamous mating.<ref name="iucn status 15 November 2021" /><ref>{{Cite journal|last1=Vincent|first1=Amanda C. J.|last2=Sadler|first2=Laila M.|date=1995-01-01|title=Faithful pair bonds in wild seahorses, Hippocampus whitei|journal=Animal Behaviour|language=en|volume=50|issue=6|pages=1557–1569|doi=10.1016/0003-3472(95)80011-5|s2cid=53192875 |issn=0003-3472}}</ref>

==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.<ref name="iucn status 15 November 2021" /> 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.<ref name="iucn status 15 November 2021" />

==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.<ref name="iucn status 15 November 2021" />

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.<ref name="iucn status 15 November 2021" />

==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.<ref name="iucn status 15 November 2021" />

==References== {{Reflist}}

==Further reading==

*[http://eol.org/pages/224695/overview Encyclopedia of Life] *[http://www.marinespecies.org/aphia.php?p=taxdetails&id=212235 WoRMS] *[https://web.archive.org/web/20180204003718/https://www.arkive.org/whites-seahorse/hippocampus-whitei/ Wildscreen Arkive] *[https://www.inaturalist.org/taxa/102838-Hippocampus-whitei iNaturalist] *[https://web.archive.org/web/20180317175447/https://www.iseahorse.org/ iSeahorse] *[https://iucn-seahorse.org/ IUCN Seahorse, Pipefish & Stickleback Specialist Group]

Category:Seahorses Category:Taxa named by Pieter Bleeker Category:Fish described in 1855 Category:Marine fish Category:Taxonomy articles created by Polbot