Hippocampus erectus is found from Cape Cod (and rarely Nova Scotia), Canada to Argentina and into the Gulf of Mexico. (Aquatic Bookshop)
Biogeographic Regions: atlantic ocean (Native )
Regularity: Regularly occurring
Type of Residency: Year-round
The seahorse, including several species in the genus Hippocampus, is one of the most unusual in appearance of all fishes. Its upright position, horse-like head set at right angles to the body, and jointed armor make it resemble a knight in a chess set. The seahorse has a prehensile tail, which it uses to hold onto seaweed and coral. The scales have been replaced by rings of about 50 rectangular bony plates, encasing the body in a semi-rigid skeleton. The eyes can swivel independently or converge to achieve binocular vision. The most distinguishing feature between the male and the female seahorse is the kangaroo-like pouch that the male has on its ventral side, used for reproduction. (Grolier, 1996)
Hippocampus erectus is a large species of seahorse, growing up to 5 inches long. H. erectus is easily separated from other species of seahorse by a pattern of dark lines on a lighter background in its coloring. H. erectus also has 18 to 21 dorsal-fin rays. (Bohlke and Chaplin, 1968, pg. 183)
Other Physical Features: bilateral symmetry
Catalog Number: USNM 30876
Collection: Smithsonian Institution, National Museum of Natural History, Department of Vertebrate Zoology, Division of Fishes
Collector(s): D. Jordan & S. Stearns
Year Collected: 1882
Locality: Pensacola, Escambia County, Florida, United States, Gulf of Mexico, Atlantic
Hippocampus erectus is strictly marine in habitat, and is found in seaweed and on coral reefs at depths of .5 - 30 m. (Aquatic Bookshop)
Aquatic Biomes: reef ; coastal
Habitat and Ecology
This species may be particularly susceptible to decline. The limited information on habitat suggests they inhabit shallow sea-grass beds (Lourie et al. 1999) that are susceptible to human degradation, as well as making them susceptible to being caught as bycatch. All seahorse species have vital parental care, and many species studied to date have high site fidelity (Perante et al. 2002, Vincent et al., in review), highly structured social behaviour (Vincent and Sadler 1995), and relatively sparse distributions (Lourie et al. 1999). The importance of life history parameters in determining response to exploitation has been demonstrated for a number of species (Jennings et al. 1998).
Habitat Type: Marine
Water temperature and chemistry ranges based on 187 samples.
Depth range (m): 0 - 2107
Temperature range (°C): 3.468 - 25.997
Nitrate (umol/L): 0.286 - 21.357
Salinity (PPS): 32.507 - 36.446
Oxygen (ml/l): 3.453 - 6.494
Phosphate (umol/l): 0.088 - 1.439
Silicate (umol/l): 0.756 - 15.466
Depth range (m): 0 - 2107
Temperature range (°C): 3.468 - 25.997
Nitrate (umol/L): 0.286 - 21.357
Salinity (PPS): 32.507 - 36.446
Oxygen (ml/l): 3.453 - 6.494
Phosphate (umol/l): 0.088 - 1.439
Silicate (umol/l): 0.756 - 15.466
Note: this information has not been validated. Check this *note*. Your feedback is most welcome.
From 1 to 73 meters.
Habitat: reef-associated. Rare in most areas, but may be locally common in certain places. Usually attached to gorgonians or seagrasses but may occur in floating @Sargassum@ or swimming freely in midwater (Ref. 9710). Those that live in @Sargassum@ usually have bony protuberances and fleshy tabs that may serve as camouflage.
Non-Migrant: No. All populations of this species make significant seasonal migrations.
Locally Migrant: No. No populations of this species make local extended movements (generally less than 200 km) at particular times of the year (e.g., to breeding or wintering grounds, to hibernation sites).
Locally Migrant: No. No populations of this species make annual migrations of over 200 km.
The seahorse, like all of the species of the family Syngnathidae, require living food. They are unable to move rapidly enough to chase their prey. Instead, the seahorse uses its elongated snout to suck in small crustaceans. Seahorses have an almost pinpoint accuracy within the 1 inch range. Young Hippocampus erectus may feed for as long as ten hours of each day and consume up to 3600 baby brine shrimp during that time. (Herald, 1961, pg. 147; Moyle and Cech,1982, pg. 294)
Life History and Behavior
Perception Channels: tactile ; chemical
Status: captivity: 4.7 years.
Lifespan, longevity, and ageing
Seahorses reproduce sexually through internal fertilization and spawn during every season. With Hippocampus erectus, as with all seahorses, it is the male that cares for the young. Male seahorses have an incubation pocket, similar to the pouch of a marsupial mammal, on the lower side of the tail, with an opening that can be closed off. During courtship, female H. erectus spray between 250 and 650 eggs into the male brood pocket, depending on the size of the individual. Development in the brood pocket lasts between 20 and 21 days. After hatching, the free embryos are carried in the pouch until they are capable of fairly active swimming. When it is time for the incubated young to be born, the prospective father holds fast to a plant stem or some other object by his prehensile tail. He bends rapidly, sharply, backward and forward; the pouch opens and a baby seahorse pops out. With brief intervals between births, the jerking motions are repeated until the pouch is emptied. Each infant seahorse emerges head first and is a swimming, independent miniature of the adult. Newborn H. erectus are about 5/8 of an inch in length, and within 8-10 months reach their maximum size of 5 inches in length. (Moyle and Cech, 1982, pg. 120; Schultz, 1948, pg. 114; National University of Singapore)
One of the complications of seahorse birth is that some of the unhatched seahorses may die within the pouch before birth, and this soon results in the formation of gas. The male then virtually becomes a balloon and is quickly buoyed to the surface, where he is immediately be picked off by some hungry fish. (Herald, 1961, pg. 148)
Average age at sexual or reproductive maturity (male)
Sex: male: 273 days.
Average age at sexual or reproductive maturity (female)
Sex: female: 273 days.
Molecular Biology and Genetics
Barcode data: Hippocampus erectus
Below is a sequence of the barcode region Cytochrome oxidase subunit 1 (COI or COX1) from a member of the species.
See the BOLD taxonomy browser for more complete information about this specimen and other sequences.
-- end --
Download FASTA File
Statistics of barcoding coverage: Hippocampus erectus
Public Records: 5
Specimens with Barcodes: 13
Species With Barcodes: 1
Seahorse populations in the wild could vanish if they continue to be exploited for traditional Chinese medicines, the aquarium trade, and as tourist curios. Countless seahorses are also lost every year with the destruction of their coral reef, sea grass, and mangrove habitats. More than 20 million seahorses are collected each year, causing some seahorse populations to crash by 50% over the last five years. These and other results from the first major study of the international trade in seahorses released by TRAFFIC, a global wildlife trade monitoring group, suggest that Hippocampus erectus should be considered threatened. (Coral Forest)
IUCN Red List of Threatened Species: vulnerable
IUCN Red List Assessment
Red List Category
Red List Criteria
- Needs updating
Hippocampus erectus is traded for use as aquarium fishes, curios and traditional Chinese medicine (TCM) (Vincent and Perry, in prep.). This species is also incidentally caught, as bycatch, in shrimp trawl and other fisheries in Florida (Baum et al. in review), Mexico (J. Baum, unpublished data), Central America (Belize, Honduras, Nicaragua) (J. Baum, unpublished data) and South America (Argentina, Brazil) (I. Rosa and J. Baum, unpublished data). This species is also affected by habitat degradation due to coastal development and pollution. Given that H. erectus is among the most commonly traded seahorse species, particularly for ornamental display, fishers' and traders' evidence of declines in seahorse availability raise concern for this species.
National NatureServe Conservation Status
Rounded National Status Rank: NNR - Unranked
NatureServe Conservation Status
Rounded Global Status Rank: GNR - Not Yet Ranked
The preferred habitat of H. erectus is also declining due to coastal development, pollution, and increased sedimentation. For example, in NE Brazil the development of shrimp farms has destroyed much of the coastal mangrove habitats where seahorses live (J. Gomezjuardo in litt. to A. Vincent Sept. 1999).
Relevance to Humans and Ecosystems
Worldwide there is a huge demand for seahorses for traditional Chinese medicine and the aquarium trade. Seahorses are considered a powerful aphrodisiac and are used to treat an array of ailments including asthma, impotence, infertility, throat infections and lethargy. Seahorses are also extremely popular in the aquarium trade and as tourist curios. (Coral Forest)
|This article needs more links to other articles to help integrate it into the encyclopedia. (February 2015)|
The lined seahorse (Hippocampus erectus), northern seahorse or spotted seahorse is a species of fish that belongs to the Syngnathidae family. H. erectus is a diurnal species with an approximate length of 15 centimeters (5.9 inches) and lifespan of one to four years. The H. erectus species can be found with a myriad of colors, from greys and blacks to reds, greens, and oranges. The lined seahorse lives in the 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.
Lined seahorses feed mainly on minute crustaceans and brine shrimp, which they suck in through their snout. They are able to suck their prey by creating a current of water leading directly into its snout. Since seahorses are weak swimmers, they must ambush their prey by blending into their surroundings, which they do rather easily. The lined seahorse's eyes can move independently of one another, allowing it to effectively scan its surroundings. The species is sexually dimorphic and it is easy to distinguish between a male and female lined seahorse. The males are larger and also have longer tails. The lined seahorse is monogamous and performs ritual dances every morning to reestablish the bond with its mate. In addition, they create clicking sounds while embracing their partner. This action occurs when they initially find their mate. The intensity of their bond is also conveyed in how they handle the death of their partner: If either the male or female should die, the mate does not automatically replace the deceased mate with a new one. Often, it fails to find a new mate in its short lifespan.
Like with other seahorses, the male lined seahorse is the caregiver. During intercourse, the female sprays her eggs into the male's brood pouch where the eggs will incubate for 20–21 days. When the juveniles are ready to hatch, the male attaches its tail to a stationary structure and begins to arch its back, back and forth, releasing the juveniles into the water column. The juveniles are approximately 11 mm at birth. They quickly begin to learn and mimic the behavior of its parent. Courtship between the male and female parents begin immediately after birth.
The habitat of the lined seahorse is diminishing due to coastal growth and pollution, which ultimately is the cause of the decreasing population. The lined seahorse is also used as Chinese medicine and is common in the aquarium trade, contributing to its "vulnerable" status.
The lined seahorse was first named Hippocampus Erectus by George Perry in 1810. "Hippocampus" translates into "horse or sea monster" in ancient Greek. The lined seahorse is a diurnal species that ranges in length from 12 cm to 17 cm; the maximum length reported for the species is 19 cm. The lined seahorse is sexually dimorphic, meaning there are distinct differences in appearances of males and females; most notably the brood pouch located on the male's abdomen which it utilized in reproduction. Males are also slightly larger in size and have longer prehensile tails than the females. In the wild, the lined seahorse has a lifespan of one to four years; however, in captivity their lifespan usually reaches the full four years. Four years is the maximum age reported for the species. They have a broad color spectrum, ranging from black, grey, brown, and green, to orange, red, and yellow. They tend to be paler on their front side. However, their colors change due to altercations in their environment, diet, anxiety or stress level, and/or mood. The lined seahorse is brawny and upright in appearance. They have an armor-like body composed of approximately fifty bony plates. Together these bony plates form the outer skeleton of the species. It is common for the species to have white lines outlining the neck area—hence its common name, "lined seahorse"—and for tiny white dots to be present on the tail. The prehensile tail consists of numerous rings and the first, third, fifth, seventh, and eleventh may protrude farther outward than the remaining. The prehensile tail following the bony plates is utilized by the seahorse to grasp onto its environment composed of seaweed and coral. The tail curls forward and is seldom aligned. When a lined seahorse is very young (two weeks to four weeks), the tail is extremely limber. The snout length is approximately half the head length of the lined seahorse. The cheek spines, located diagonally down from the eye on either side may be single or double. In total, the lined seahorse has eleven trunk rings, 34–39 tail rings, 16–20 dorsal fin rays, and 14–18 pectoral fin rays. The pectoral fin is level with the eye on each back side of the lined seahorse's head. The dorsal fin is located on the back of the skeleton and is level with the stomach–chest area. Female dorsal fins are slightly larger than the male's and are located lower on the back. The eyes of the lined seahorse can concentrate together, or they can operate independently of one another. The lined seahorse may be considered sexually mature as early as four months; however, it is typically about eight months. The minimum size of a sexually mature lined seahorse is 5.6 cm.
Habitat and distribution
The lined seahorse habitat spans from the northern point of Nova Scotia, Canada,to the southern area of Venezuela in South America. They can be found on the east coast of America in Connecticut, Delaware, Florida, Georgia, Louisiana, Maryland, New Jersey, New York, and North Carolina, as well as in the waters surrounding Mexico and the Caribbean. Species found in Brazil seem to be of a different species; however, more research is needed to determine this proposal. The lined seahorse is native to the following locations: Nova Scotia, Canada, United States, Bermuda, Cuba, Mexico (Veracruz, Yucatán), Haiti, Saint Kitts and Nevis, Belize, Honduras, Nicaragua, Costa Rica, Panama, Guatemala, and Venezuela.
The species is found in depths of water up to seventy-three meters. Adults can be found swimming freely in the water column or attached to a stationary object. Juveniles usually swim near the surface. The habitat of the lined seahorse consists of marine vegetation, such as suspended Sargassum, seagrass, sponges, and mangroves. Depending on the season, the species can be found in shallow waters or deep waters along beaches, oyster beds, and banks covered in vegetation, as well as in bays or salt marshes. Lined seahorses can often be found with their tails wrapped around crab pots as well. In the winter, the seahorses are more prominent in deeper waters, versus warmer months, where they are usually found in shallow waters attached to vegetation.
The temperature in which the H. erectus dwells varies with the different latitudes. Temperature has an effect on gonad development, brood size, and juvenile development and survival. Many lined seahorses experience temperature fluctuations during the daily tide cycles, the different seasons of each year, and due to precipitation or runoff. Adults have the ability to migrate to deeper waters during cold seasons. A study showed that the highest survival and growth rate of juveniles occurred at 28 to 29 degrees Celsius in captivity. In addition to temperature, there is also a large range of salinity concentration depending on the location that affect the species. The most common salinity is 25 to 35 ppt. In captivity, the species is most commonly kept at 35 ppt. The H. erectus is the only species of seahorse native to the Chesapeake Bay.
The lined seahorse utilizes its elongated snout in order to consume its prey, consisting primarily of minute crustaceans, mollusks, and zoo plankton. Unfortunately, some captive parental males have been known to cannibalize small number of its own fry, or juveniles, following its release into natural habitat. In order to ambush its prey, the seahorse employs color changes to camouflage itself with its surrounding environment, locates the prey, and then jerks its head upward, forcing the prey in the right position to be sucked in through its tubular snout. The lined seahorse is highly accurate, especially if its prey is within one inch from its snout. Overall, this process is quick and accurate. A growing lined seahorse may feed continuously for up to ten hours a day, engulfing approximately 3,600 baby brine shrimp.
Predators and parasites
The predators of the lined seahorse include crabs, rays, various type of sea turtles, skates, seabirds, sharks, tuna, and dolphinfish. Although their camouflage tactics reduce their risk of becoming prey, their poor swimming abilities increase their likelihood of being consumed by their predators, especially large fish.
A unique characteristic of the lined seahorse (and other species of seahorse) is their practice of monogamy: the male and female seahorses choose partners that they will continue to mate with for their lifetime. The monogamous characteristics of the lined seahorse include ritual dances with their partner that they perform every morning. These dances establish their permanent relationship as mates. If a male or female lined seahorse should lose their partner for any reason, it takes time before they replace their mate.
Lined seahorses are weak swimmers; they swim in an erect position. In comparison to their fins, the lined seahorse's body is too large, another reason why they are poor swimmers. They do not swim for long periods of time, nor do they travel far distances, unless they are migrating. The lined seahorse propels its body forward with its dorsal and pectoral fins, which they move rapidly back and forth. These fins are also utilized in directing their bodies throughout the water and beat twenty to thirty times per second, making them almost invisible at first glance.
In addition to monogamy, the lined seahorse also cues into sound-making in the mating process. The seahorses have a crown-like bony crest called a coronet located on the backside of their head at the edge of the skull. Each coronet is unique to the organism, just as a fingerprint is unique to every human. The coronet resembles a star pattern and is attached rather loosely and has sharp edges. As the seahorse lifts its head, the edge of the skull slides beneath the coronet and out when the seahorse bows its head. As the skull's edge slides beneath and out from the coronet, a clicking sound is produced. Mating seahorses swim slowly together, alternating their clicking sounds, until they embrace one another. Once the male and female seahorse embrace, the sounds from both the male and female unify, becoming indistinguishable from one another. This action creates a louder, consecutive sound, further establishing their bond.
Like all species of seahorses, the lined seahorse reproduces sexually, laying eggs every season. In addition, the male is the parent that looks after the newborn seahorses. The reproduction process begins at the initiation of the courtship process. Courtship extends for a couple of days and during this process, both the male and female may change to a pale color. The male enlarges his pouch to indicate his desire to pursue the female. Once they are established as monogamous mates though dances and clicking sounds, intercourse takes place.
During intercourse, the female sprays her eggs into the males pouch, which is called a "brood pouch", where they are fertilized and sealed. Females clutch size can be equal to or greater than one thousand and the males' brood size can range from 97 to 1,552 eggs. The number of eggs the female produces varies depending on the size of the seahorse. Six hundred and fifty eggs can be carried by a single male at one time. The eggs are 1.5 mm in diameter. When the eggs are being incubated within the male's pouch, the embryos are provided oxygen via an extensive capillary system. Through this system, the sodium and calcium levels can be altered in order to maintain homeostasis within the pouch environment. When the embryos are approaching birth, the pouch environment is very similar to the seawater. The gestation period lasts for 20–21 days. When the time finally approaches, the male latches his prehensile tail onto a supportive object while he braces back and forth, until the developed seahorses escape from the pouch. The bracing continues until all seahorses have successfully escaped the pouch. However, unhatched seahorses that have died will create a gas within the male's pouch. Soon after, the male seahorse inevitably floats to the surface, only to become easy prey in the marine food chain.
Juveniles are approximately 11 mm at birth for three days and are considered embryos until they are capable of swimming on their own. Juveniles do not reach maximum size until they are 8–10 months of age. It is estimated by scientists that only about two juveniles grow up to be adults out of the hundreds that are hatched. In captivity, the species maintained a vertical growth rate of 0.55 mm a day for 100 days. Male juveniles develop pouches when they are 5–7 months old. The juvenile seahorses quickly develop the characteristic of the adult lined seahorse. After birth, courtship begins once again. Breeding occurs in the months of May through October in the Chesapeake Bay. July is when the lined seahorse population is the greatest in Florida.
The minimum habitat requirements for captive lined seahorses consist of a tank 18 inches vertical in height and 20 to 25 gallons for a pair, 30 to 40 gallons for two pairs. The tank should be kept at a constant temperature between 22 and 25 degrees Celsius (72 and 77 degrees Fahrenheit). The ph value should remain between 8.1 and 8.4 and the specific gravity between 1.020 and 1.025.
The lined seahorse is an easy going species and will not be a threat to other fish that could possibly be in an aquarium. The seahorse thrives in an environment with objects it can hide around and attach its tail to. The H. erectus species should be fed multiple times throughout the day, rather than less amount of larger meals. In captivity, the lined seahorse is often fed live or frozen nauplius or Mysis shrimp, grass shrimp, adult brine shrimp, gammarids and caprellid amphipods, krill fish fry, and frozen krill.
The lined seahorse species was listed as vulnerable since 1996 and was listed as vulnerable in the 2003 IUCN assessment, indicating no significant improvements in protective factors. Due to loss or harm to their habitat by pollution and coastal development, accidental catch, or by purposeful catch, the lined seahorse's population is starting to dwindle, by values of at least thirty percent, probably since 1996 when changes in its population size were noted. The H. erectus is a very common species of the aquarium trade, which also affects the population remaining in the wild. The lined seahorse is also used for ornamental decoration and for Chinese medicine. Despite being a popular seahorse for aquarium trade and Chinese medicine, it is only suspected that the species could be a potential candidate for commercial aquaculture. If successful, this could positively affect the population of the lined seahorse.
|Wikimedia Commons has media related to Hippocampus erectus.|
|Wikispecies has information related to: Hippocampus erectus|
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- Rosamond Gifford Zoo Volunteers (July 23, 2005). "Lined Seahorse".
- "H. erectus". Seahorse Source, Inc. 2005. Retrieved 31 October 2011.
- Gardiner, Nick, University of Michigan. "Hippocampus erectus". Animal Diversity Web. Retrieved 31 October 2011.
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- "Hippocampus erectus". IUCN Red List of Threatened Species Version 2011 Project Seahorse 2003.
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- Project Seahorse Team". "Introduction to seahorses". Project Seahorse.
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- Hauter, Stan and Debbie. "Lined Seahorse Profile - Facts, care info, pictures and more on H. erectus". About.com.
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