Animal Diversity Web

Ge­o­graphic Range

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

Habi­tat

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

Phys­i­cal De­scrip­tion

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

Re­pro­duc­tion

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 (female)
  Sex: female

  273 days

  AnAge

• Average age at sexual or reproductive maturity (male)
  Sex: male

  273 days

  AnAge

Lifes­pan/Longevity

• Average lifespan
  Status: captivity

  4.7 years

  AnAge

Be­hav­ior

Hip­pocam­pus erec­tus swims weakly, pro­pelled largely by the rapid mo­tion of its dor­sal fin and pec­toral fins. H. erec­tus, when mov­ing from one perch to an­other, moves so slowly that it would take one about 5 min­utes to cross a bath­tub. (Grolier, 1996, Schultz, 1948, pg. 12)

The sea­horse is un­usual in that it ac­tu­ally prac­tices monogamy, mean­ing that a sea­horse will mate ex­clu­sively with the same part­ner dur­ing their life­time. Mem­bers of a pair per­form greet­ing dances every morn­ing to con­firm their bond and are slow to find a new mate if their part­ner dis­ap­pears or dies. (Coral For­est)

Sound-mak­ing has a sex­ual sig­nif­i­cance in Hip­pocam­pus erec­tus, as it does in all sea­horses, which pro­duce snap­ping or click­ing noises by toss­ing their heads. At the back of the head is a star-shaped bony crest known as the coro­net. This has a loose ar­tic­u­la­tion with the rear edge of the skull. When a sea­horse sud­denly lifts its head, this edge slips under the coro­net, and then, as the head is low­ered, snaps out, an ac­tion which pre­sum­ably pro­duce the sound. "A mat­ing pair of sea­horses con­sisted of slow swim­ming, ei­ther to­gether or apart, ac­com­pa­nied by oc­ca­sional noisy snap­ping of the head. Clicks were often pro­duced al­ter­nately by the fishes, and dur­ing their ac­tual em­brace, these sounds were loud and al­most con­tin­u­ous." (Mar­shall, 1966, 171)

• Key Behaviors
• natatorial
• motile

Com­mu­ni­ca­tion and Per­cep­tion

• Perception Channels
• tactile
• chemical

Food Habits

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)

Eco­nomic Im­por­tance for Hu­mans: Pos­i­tive

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)

Con­ser­va­tion Sta­tus

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

  Vulnerable
  More information

Other Com­ments

Sea­horses are also known for their pre­hen­sile tails. In the first two weeks or month of life, a young sea­horse is ex­tremely agile and may bend the tail back­ward in a re­verse cres­cent, but the tail is pre­hen­sile only in a for­ward di­rec­tion. Adult sea­horses sel­dom carry the tail in a straight po­si­tion, usu­ally hav­ing it coiled for­ward. (Mar­shall, 1966, pg. 37)

Con­trib­u­tors

Nick Gar­diner (au­thor), Uni­ver­sity of Michi­gan-Ann Arbor.

Ref­er­ences

Aquatic Book­shop. http://​www.​seahorses.​com/​SEA_​PIPE/​seahorse/​hippocam/​kuda.​htm

Bohlke, J. E., and C. C. G. Chap­lin. 1968. Fishes of the Ba­hamas and Ad­ja­cent Trop­i­cal Wa­ters, Sec­ond Edi­tion. Uni­ver­sity of Texas Press, Austin, Texas.

Coral For­est. http://​www.​blacktop.​com/​coralforest/​SeaHorse.​html

Grolier's Elec­tronic En­cy­clo­pe­dia. 1996.

Her­ald, E. S. 1961. Liv­ing Fishes of the World. Dou­ble­day & Com­pany, Inc., Gar­den City NY.

Mar­shall, N. B. 1966. The Life of Fishes. The World Pub­lish­ing Com­pany, Cleve­land.

Moyle, P. B. and J. J. Cech, Jr. 1982. Fishes: An In­tro­duc­tion to Ichthy­ol­ogy. Pren­tice-Hall, Inc. En­gle­wood Cliffs New Jer­sey.

Na­tional Uni­ver­sity of Sin­ga­pore. http://​www.​nus.​sg/​Courses/​khoo/​ab3214/​new0001.​htm

Schultz, L. P. 1948. The Ways of Fishes. D. Van Nos­trand Co., Inc. New York.