Pacific seahorse

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Pacific seahorse
Hippocampus ingens.jpg
CITES Appendix II (CITES) [2]
Scientific classification OOjs UI icon edit-ltr.svg
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Class: Actinopterygii
Order: Syngnathiformes
Family: Syngnathidae
Genus: Hippocampus
Species:
H. ingens
Binomial name
Hippocampus ingens
Girard, 1859
Synonyms [3]
  • Hippocampus ecuadorensis Fowler, 1922
  • Hippocampus gracilis Gill, 1862
  • Hippocampus hildebrandi Ginsburg, 1933

The Pacific seahorse, also known as the giant seahorse, (Hippocampus ingens) is a species of fish in the family Syngnathidae. Their genus name (Hippocampus) is derived from the Greek word hippos, which means "horse" and campus, which means "sea monster." [4] This species is the only seahorse species found in the eastern Pacific Ocean. [5]

Contents

Description

A pacific seahorse anchoring itself in eelgrass. Hippocampus ingens, Monterey.jpg
A pacific seahorse anchoring itself in eelgrass.

Hippocampus ingens are one of the largest seahorses, with adult pacific seahorses ranging in size from 12 to 19 centimetres (4.7 to 7.5 in) in height, with a maximum known size of 30 centimetres (12 in). Offspring are approximately 9 mm after birth. [6] While large compared to others of their kind, their size hinders them in the conservation world. Minimum size limits are a common and favored conservation tool, usually starting at 10 cm. Thus, it is crucial that Pacific seahorses are accurately measured when they reach sexual maturity, for it determines if they will be protected or not. [7]

Pacific seahorses can be a variety of colors, including green, brown, maroon, grey, and yellow. Males can be distinguished from females by their prominent keel. [6]

Pacific seahorses share the common traits of seahorses, including a prehensile tail used for anchoring, skin instead of scales, a digestive tract without a distinct stomach, no teeth, and the ability to move each eye independently. [8] It is one of the six species listed as "under the greatest threat from unsustainable levels of harvest and international trade" by the Convention on International Trade in Endangered Species of Wild Fauna (CITES). [7]

Distribution and habitat

Range of the Pacific seahorse Pacific seahorse range.jpg
Range of the Pacific seahorse

The pacific seahorse is distributed in the Pacific Ocean from Baja California to Chile, with an additional transient population off of San Diego.The only known oceanic island population occurs around the Galapagos Islands [5] with some additional populations also located in Northern Peru.

Pacific seahorses are nocturnal and known to inhabit a variety of sub-tidal habitats to a maximum depth of 60 metres (200 ft). [8] Habitats include mangroves, seagrass meadows, rocky reefs, coral reefs and sponges. [5] [8] Other common habitats are sea kelp and eelgrass. They also camouflage around the branches of gorgonians and black corals. [4]

South America specifically is home to an abundance of aquatic ecosystems. As a result, this region is more susceptible to environmental crime and many species such as the Pacific seahorse are affected by this. Furthermore, Peru trades the most pacific seahorses and this environmental crime in this country regarding the species is very high. [9]

The first record of Hippocampus ingens in Guadalupe Island, Mexico, was in November 2015. This is a northern oceanic island, differing from its usual Eastern Pacific locations. The presence of Hippocampus ingens at this new location could be due to the fact that its population is vulnerable as well as long distance dispersal methods, which other seahorse species have recently been doing. [10]

Convention on International Trade in Endangered Species of Wild Fauna (CITES) data did not become available for seahorses until 2004, and thus until then Latin American countries were not thought of to be heavily involved in international seahorse trade. However, it is now known that countries such as Peru and Mexico are some of the greatest culprits of this trade and although the Pacific seahorse is an Eastern Pacific species, its trade and exploitation has gone largely beyond this region. [7]

Behavior

Reproduction

Female pacific seahorses in captivity have been observed producing small broods at three months of age. Sexually mature females often develop a dark patch below the anal fin. Males reach sexual maturity at around 5.4 centimetres (2.1 in) in height. Unsuccessful reproductive activity in captivity has been noted at around three months of age, with successful pregnancies as early as six months of age. [6]

Like all seahorses, females deposit their eggs in the brood pouch of the male, where they are subsequently fertilized by the male and sealed into the pouch. As the embryos develop, the fluid inside the pouch changes in salinity to acclimate the embryos to the salinity of the surrounding sea water. Research suggests that pacific seahorse males can brood up to 2000 eggs at once, and may brood multiple times in a breeding season. At the end of the fourteen day gestation period, the male goes into labor and must force the young out of the pouch one at a time, which sometimes takes hours. [6] [8]

Development

Birth marks the end of parental care, as young are born fully self-sufficient. It has been hypothesized that juveniles spend the first few months after birth in the open ocean. This is based on their large juvenile dorsal fin and lack of juvenile anchoring behavior, and not specific field observation. [6]

Although they do not have a stomach, Hippocampus ingens juveniles have a well-developed digestive system. They have good immune function and their intestine does most of the work, for it has a larger area since there is no stomach present. Furthermore, the species has enough enzymes to digest its major nutrients, including those to account for the higher than average lipid requirements. [11]

Diet

Hippocampus ingens in a tank in the Ripley's Aquarium of Canada. Giant Seahorse- in total darkness in a remote corner (27798709462).jpg
Hippocampus ingens in a tank in the Ripley's Aquarium of Canada.

Hippocampus ingens diet consists of small organisms that live on the bottom of the sea such as mysids, small crustaceans, and other plankton. Like most seahorses, Pacific seahorses are ambush predators, meaning that they camouflage in their habitats and wait for their prey to pass. They then suck their prey in and swallow it whole, for they do not have teeth. [4]

Evolutionary history

Hippocampus ingens have low genetic diversity, which is one of the reasons they are a vulnerable species, and thus it is difficult identify a geographic origin for this species. Researchers are looking into possibly sequencing loci of the species or microsatellite markers to gain more information about the geographic origin of the species and how they are relocating to new locations. [7]

However, it is known that the lineage of seahorses leading to modern pacific seahorses diverged from slender seahorses after the rise of the Isthmus of Panama, between 4 and 5 mya. Pacific seahorses and Fisher's seahorses split from this lineage 2.5 to 3 mya. [5]

Although little research has been conducted regarding the origins of the Hippocampus ingens, one study looked at the histological structure of the species' digestive tract as well as their digestive enzymes and found informative data. The histological structure of their intestine is similar to that of seahorse species that also lack a stomach (agastric teleosts) such as the H. abdomnialis and the H. guttulatus. Thus, these species may have split from each other from a common ancestor, but more than just morphological data would be needed to confirm this observation. [11]

Conservation status

Pacific seahorse in an aquarium. Hippocampus ingens 2.jpg
Pacific seahorse in an aquarium.

Threats

Pacific seahorses face many of the same threats that other seahorses face; over 20 million seahorses are sold each year to be used in Chinese medicine, the aquarium trade, or dried as curios. Mexico and Peru are the largest exporter of pacific seahorses, selling more than 1 dry ton annually. [5] Seahorses are particularly susceptible to over-harvesting due to characteristics such as low fecundity, monogamous mating, long development of embryos, low dispersal ability, and limited geographic distribution. [8] Habitat degradation also poses a threat to Pacific seahorses as humans destroy and pollute their habitats. Commercial fishing also poses as threat to Pacific seahorses as fisherman often catch and kill them in their large fishing nets as bycatch. [4]

Chinese medicine is one of the main risks to the Hippocampus ingens species, thereby making them one of the most vulnerable fish populations in the world. Hippocampus ingens account for the majority of species identified in Chinese medicinal markets around the world in places such as San Francisco's Chinatown. [7] This species specifically is favorable for this industry due to its large size (compared to other seahorses) and smooth texture. Powdered forms of these seahorses are very profitable and thus those who partake in these illegal activities are always finding new ways to conduct their methods. For instance, seahorse powder is not particularly hard to get through customs in many places, for it can be easily disguised as something legal such as plant extract or other substances. These powdered forms are used as "at home remedies" for many common illnesses. For example, some countries mix the powder in various liquids to treat common respiratory illnesses. [9]

Another ways humans exploits seahorses such as the Pacific seahorse is they kill and use them to make crafts and jewelry. Locals will kill seahorses for this reason and sell them to tourists. There are even websites where seahorse products are sold online. [4]

Efforts

There are some efforts to stop the exploitation of seahorses such as Hippocampus ingens, but little enforcement. For example, in Mexico Hippocampus ingens are listed as a species subject to special protection, but Mexico is still one of the leading contributors to the issue. Additionally, many countries have tried to get legislature involved and implement bans against some of the illegal activity involving the seahorses. For instance, in 2004, the entire genus Hippocampus was included in appendix II of CITES. [8] This action was taken by the Convention on International Trade in Endangered Species of Wild Fauna and Flora and as a result, many countries directly involved in the illegal trade of these species, such as Peru, made more formal bans on it through their legislature. Nonetheless, illegal activity involving the species still continued and confiscation rates were around the same as before the ban was put into place. [12]

Because the main form of the confiscation of these seahorses is powder, chemical identification of the powder would be extremely useful in working towards prevention of illegal trade and trafficking of the species. If a protocol was constructed to determine identify the powdered substance, then it would be much easier for law officials to track the criminal activity being done and hold those accountable. [9]

Additionally, scientists and researchers are searching for new and innovative ways to combat exploitation of Hippocampus ingens and increase the size of their populations. One study in particular took the angle of possibly trying to cultivate the existing seahorse populations by supplementing their diet. They enriched their diet with different foods in the first months of the Hippocampus ingens' life and saw a significant effect on the seahorses' survival. [13]

Related Research Articles

<span class="mw-page-title-main">Seahorse</span> Genus of bony fishes

A seahorse is any of 46 species of small marine bony 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.

<span class="mw-page-title-main">Pipefish</span> Subfamily of fishes

Pipefishes or pipe-fishes (Syngnathinae) are a subfamily of small fishes, which, together with the seahorses and seadragons, form the family Syngnathidae.

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

The big-belly seahorse or pot-bellied seahorse is one of the largest seahorse species in the world, with a length of up to 35 cm (14 in), and is the largest in Australia. Seahorses are members of the family Syngnathidae, and are teleost fishes. They are found in southeast Australia and New Zealand, and are listed on Appendix II of CITES.

<i>Hippocampus bargibanti</i> Species of fish

Hippocampus bargibanti, also known as Bargibant's seahorse or the pygmy seahorse, is a seahorse of the family Syngnathidae found in the central Indo-Pacific area.

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

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

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

The tiger tail seahorse is a species of fish in the family Syngnathidae. The species was first described by Theodore Cantor in 1850. It is found in India, Indonesia, Malaysia, the Philippines, Singapore, Thailand and Vietnam. Its natural habitats are subtidal aquatic beds and coral reefs. It is threatened by habitat loss.

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

Hippocampus coronatus, commonly known as the high-crowned seahorse or crowned seahorse, is a species of fish of the family Syngnathidae. It is endemic to the Pacific coastal waters of Japan, where it lives among Zostera seagrasses. It can grow to lengths of 10.8 centimetres (4.3 in), but is more commonly 6 centimetres (2.4 in). Individuals feed mainly on small crustaceans such as gammarid amphipods and copepods, although this can vary by size, with smaller individuals consuming copepods while larger individuals feed on amphipods and mysids. This species is ovoviviparous, with males brooding eggs in a brood pouch before giving birth to live young. Breeding season occurs from June to November, with females and males reaching sexual maturity at 6.9 centimetres (2.7 in) and 7.3 centimetres (2.9 in) respectively. Male brood size ranges from 12–46. The International trade in this species has been monitored through Appendix II of the CITES licensing system since 2004 and a minimum size of 10 centimetres (3.9 in) applies to traded specimens.

<span class="mw-page-title-main">Denise's pygmy seahorse</span> Species of fish

Hippocampus denise, also known as Denise's pygmy seahorse or the yellow pygmy seahorse, is a seahorse of the family Syngnathidae native to the western Pacific.

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

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.

<i>Hippocampus kuda</i> Species of seahorse

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 populations formerly treated as the separate species Hippocampus fuscus, now a synonym of H. kuda.

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

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.

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

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. 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.

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

The dwarf seahorse is a species of seahorse found in the subtidal aquatic beds of the Bahamas and parts of the United States. It is threatened by habitat loss. According to Guinness World Records, it is the slowest-moving fish, with a top speed of about 5 feet (1.5 m) per hour.

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

The short-snouted seahorse is a species of seahorse in the family Syngnathidae. It is 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.

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

The lined seahorse, northern seahorse or spotted seahorse, is a species of fish that belongs to the family Syngnathidae. H. erectus is a diurnal species with an approximate length of 15 cm and lifespan of one to four years. The H. erectus species can be found in myriad colors, from greys and blacks to reds, greens, and oranges. The lined seahorse lives in the western Atlantic Ocean as far north as Canada and as far south as the Caribbean, Mexico, and Venezuela. It swims in an erect position and uses its dorsal and pectoral fins for guidance while swimming.

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

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.

<i>Hippocampus pontohi</i> Species of fish

Hippocampus pontohi, also known as Pontoh's pygmy seahorse or the weedy pygmy seahorse, is a seahorse of the family Syngnathidae native to the central Indo-pacific. Named after Hentje Pontoh, the Indonesian dive guide from Bunaken (Manado) who first brought these pygmy seahorses to attention.

<i>Hippocampus patagonicus</i> Species of fish

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.

<i>Hippocampus haema</i> Species of fish

Hippocampus haema, the Korean seahorse, is a seahorse of the family Syngnathidae native to the northern Pacific Ocean, and it usually lives in Sargassum and weeds on shallow soft bottom habitats from 0 to 18 m depth. The Korean seahorse is the most common seahorse in Korean waters so that the scientific name 'haema' is named from 'seahorse' in Korean. The Japanese name 'Himetatsu' is derived from its smaller shape such as body and coronet rather than the shape of a sister species, crowned seahorse. This species had been repeatedly misidentified as crowned seahorse and Shiho's seahorse before a taxonomic review. However, the two genuine species do not live in Korean waters, therefore this species was handled by naming a new scientific name, Hippocampus haema. It can grow to lengths of 11 centimeters, but more commonly 6 to 8 centimeters as adult. Namely, the length of juvenile is 1 to 5 centimeters, whereas and the lengths of males and females reaching sexual maturity are considered as ca. 5 centimeters with or without male brood pouch. However, sex determination of this species is considered as ca. 2 centimeters from anatomic examination of gonad. This species has sexual dimorphism, the difference is male has a longer tail, while female has a longer trunk for same size. Breeding season of this species is from April to October or May to November, relating to warm water temperature. The number of fertilized egg or larvae inside the male brood pouch were 38.3±14.8 (20-76), and the number of fecundity identified from female were 47.2±8.6 (31-59). The female-to-male ratio was 1:1.7, indicating the dominance of males.

References

  1. ↑ Pollom, R. (2017). "Hippocampus ingens". IUCN Red List of Threatened Species . 2017: e.T10072A54905720. doi: 10.2305/IUCN.UK.2017-3.RLTS.T10072A54905720.en . Retrieved 15 November 2021.
  2. ↑ "Appendices | CITES". cites.org. Retrieved 2022-01-14.
  3. ↑ Froese, Rainer; Pauly, Daniel (eds.) (2018). "Hippocampus ingens" in FishBase. February 2018 version.
  4. 1 2 3 4 5 "Pacific Seahorses ~ MarineBio Conservation Society". 2017-05-18. Retrieved 2022-11-29.
  5. 1 2 3 4 5 Saarman, Norah; Louie, Kristina; Hamilton, Healy (2010). "Genetic differentiation across eastern Pacific oceanographic barriers in the threatened seahorse Hippocampus ingens" (PDF). Conservation Genetics. 11 (5): 1989–2000. Bibcode:2010ConG...11.1989S. doi: 10.1007/s10592-010-0092-x .
  6. 1 2 3 4 5 Gomezjurado, Jorge (2005). "Pacific Seahorse, Hippocampus ingens". Synthnathid Husbandry in Public Aquariums Manual.
  7. 1 2 3 4 5 Sanders, Jon G.; Cribbs, Jennifer E.; Fienberg, Harris G.; Hulburd, Greg C.; Katz, Laure S.; Palumbi, Stephen R. (2008-02-01). "The tip of the tail: molecular identification of seahorses for sale in apothecary shops and curio stores in California". Conservation Genetics. 9 (1): 65–71. Bibcode:2008ConG....9...65S. doi:10.1007/s10592-007-9308-0. ISSN   1572-9737. S2CID   15874239.
  8. 1 2 3 4 5 6 Foster, S.J.; A.C.J., Vincent (2004). "Life history and ecology of seahorses: implications for conservation and management". Journal of Fish Biology. 65 (1): 1–61. Bibcode:2004JFBio..65....1F. doi: 10.1111/j.0022-1112.2004.00429.x .
  9. 1 2 3 Marín, Alan; Alfaro, Ruben; Villegas-Llerena, Claudio; Reyes-Flores, Lorenzo E.; Alvarez-Jaque, Irina B.; Robles, Christian; Ingar, Claudia; Yzásiga-Barrera, Carmen G.; Calado, Leonardo L.; Zelada-Mázmela, Eliana (2021-08-01). "Molecular tools against the illegal exploitation of the threatened Pacific seahorse Hippocampus ingens Girard, 1858". Journal for Nature Conservation. 62: 126030. Bibcode:2021JNatC..6226030M. doi: 10.1016/j.jnc.2021.126030 . hdl: 20.500.12955/1480 . ISSN   1617-1381.
  10. ↑ Becerril-Garcia, E. E.; Petatan-Ramirez, D.; Ortiz-Aguirre, I.; Ayala-Bocos, A. (April 2018). "First record of the Pacific seahorse Hippocampus ingens in Guadalupe Island, Mexico: hippocampus ingens from guadalupe island". Journal of Fish Biology. 92 (4): 1207–1210. doi:10.1111/jfb.13567. PMID   29516521.
  11. 1 2 Corona-Rojas, Daniela; Peña, Renato; Rodríguez-Jaramillo, Carmen; Tovar-Ramírez, Dariel; Hinojosa-Baltazar, Patricia; Corona-Rojas, Daniela; Peña, Renato; Rodríguez-Jaramillo, Carmen; Tovar-Ramírez, Dariel; Hinojosa-Baltazar, Patricia (September 2021). "Histological structure of the digestive tract and digestive enzymatic activity of juvenile Pacific seahorse (Hippocampus ingens)". Latin American Journal of Aquatic Research. 49 (4): 565–575. doi: 10.3856/vol49-issue4-fulltext-2673 . ISSN   0718-560X.
  12. ↑ Alfaro-Shigueto, Joanna; Alfaro-Cordova, Eliana; Mangel, Jeffrey C. (June 2022). "Review of threats to the Pacific seahorse Hippocampus ingens (Girard 1858) in Peru". Journal of Fish Biology. 100 (6): 1327–1334. Bibcode:2022JFBio.100.1327A. doi:10.1111/jfb.15058. ISSN   0022-1112. PMID   35420161. S2CID   248155812.
  13. ↑ Ortiz-Aguirre, Ismael; Dávalos, Carlos Rangel; Pacheco-Vega, Juan Manuel (2018-04-27). "Effect of Food Enrichment on the Survival of Hippocampus Ingens Girard, 1858 Alevine under Semicontroled Conditions". CICIMAR Oceánides. 33 (1): 25–32. doi: 10.37543/oceanides.v33i1.200 . ISSN   2448-9123.
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