Pygmy seahorse Worldwide, scientists recognize 46 species of seahorse , the smallest no bigger than a peanut and the largest the size of a big banana. They are pipefish and sea dragons belong to the the genus Hippocampus, a word derived from ancient Greek for “horse” and “sea monster.” [Source: Jennifer S. Holland, National Geographic, March 15, 2022]
Among the more colorful and interesting species are the Pacific seahorse (Hippocampus ingens) Tiger tail seahorse (Hippocampus comes), Long-snouted seahorse (Hippocampus guttulatus), Pot-bellied seahorse (Hippocampus abdominalis), Barbour’s seahorse (Hippocampus barbouri), Short-snouted seahorse (Hippocampus hippocampus), White’s seahorse (Hippocampus whitei) and Dwarf seahorse (Hippocampus zosterae). The Knysna seahorse (Hippocampus capensis) is an endangered species thus far found only in three South African estuaries.
The short-snouted seahorse (Hippocampus hippocampus) lives off of Europe. Wild populations in a shallow coastal lagoon in southern Portugal have been studied. During the study period (2000-2004), reproduction peaked in July and August. Juveniles in the lagoon established small home ranges. Courtship behaviours were consistent with the maintenance of pair bonds and males brooded multiple batches of young per year. Estimated annual reproductive output averaged 871 young. [Source: Project Seahorse]
The common seahorse (Hippocampus kuda) has traditionally been widely used traditional Chinese medicine. The lined seahorse (Hippocampus erectus) is an Atlantic species that mainly inhabits shallow sea beds or coral reefs. It is widely used in traditional Chinese medicine today and efforts have been made to raise it fish farms and tanks.
The pot-bellied seahorse ( Hippocampus abdominalis) is a temperate-water species also known as the big-bellied seahorse thought be is socially promiscuous with conventional sex roles — different than monogamy of most seahorse species. Scientists wrote: In laboratory populations we observed promiscuous courtship behaviour and sex-role reversal in high density, female-biased field populations of H. abdominalis. Despite promiscuous courtship behaviour, all assayed male seahorses were genetically monogamous in both laboratory and wild populations. The complete mitochondrial genome of the pot-belly seahorse was announced by Chinese scientists in 2016
Websites and Resources: Animal Diversity Web (ADW) animaldiversity.org; National Oceanic and Atmospheric Administration (NOAA) noaa.gov; Fishbase fishbase.se ; Encyclopedia of Life eol.org ; Smithsonian Oceans Portal ocean.si.edu/ocean-life-ecosystems ; Woods Hole Oceanographic Institute whoi.edu ; Cousteau Society cousteau.org ; Monterey Bay Aquarium montereybayaquarium.org ; MarineBio marinebio.org/oceans/creatures
The dwarf seahorse (Hippocampus zosterae) is 2.5 centimeters long and has a lifespan of one year. The third smallest seahorse species in the world, it is found in seagrass beds in the Gulf of Mexico, the Atlantic Coast of Florida, and the Caribbean.[Source: NOAA]
The dwarf seahorse (Hippocampus zosterae) is widely distributed throughout near-shore habitats of the Gulf of Mexico and is of commercial significance in Florida, where it is harvested for the aquarium and curio trades. It feeds on copepods. One study reported: Using phytoplankton as a tracer, we recorded and reconstructed 3D flow fields around the head of the seahorse and its prey during both successful and unsuccessful attacks to better understand how some attacks lead to capture with little or no detection from the copepod while others result in failed attacks. Attacks start with a slow approach to minimize the hydro-mechanical disturbance which is used by copepods to detect the approach of a potential predator. Successful attacks result in the seahorse using its pipette-like mouth to create suction faster than the copepod's response latency. As these characteristic scales of entrainment increase, a successful escape becomes more likely. [Source: “Predation by the Dwarf Seahorse on Copepods: Quantifying Motion and Flows Using 3D High Speed Digital Holographic Cinematography — When Seahorses Attack!” by Gemmell, Brad; Sheng, Jian; Buskey, Ed, 2008-11-01]
The dwarf seahorse is not listed as threatened or endangered under the Endangered Species Act. Protected Status: Convention on International Trade in Endangered Species (CITES) Appendix II, which lists species not necessarily threatened with extinction now but may become so unless trade is closely controlled: Throughout Its range. Threats: Habitat loss, Oil spills and energy exploration, Harvesting
World's Smallest Seahorse
In 2003, marine biologist Sara Lourie, a member of the University of British Columbia-based Project Seahorse marine conservation team, announced she identified the world's smallest known species of seahorse. According to press release: Adults of the new species, a pygmy seahorse known as Hippocampus denise, are typically just 16 millimeters long — smaller than most fingernails. In the past they have been mistaken for the offspring of other species of seahorses. "Denise" is derived from Dionysus, the Greek god of wine, and means "wild or frenzied," which seems appropriate, according to Lourie. "Compared with other small seahorses, they've active little creatures," Lourie she says. Project Seahorse, University of British Columbia, News Release May 9 2003
Because it lives among the deeper corals and is a master of camouflage, the diminutive new fish may be safe from the over-exploitation threatening other seahorse species. But with only a handful of sightings on record, it's hard to know what risks they face, warns Lourie. Heavy-duty trawling gear that can flatten reefs is one potential threat. Underwater tourism is another. "Divers and photographers could possibly love these animals to death," she says.
The tiny seahorse lives tropical waters of the western Pacific Ocean, between 13 and 90 meters beneath the surface; often found attached to coral seafans, primitive animals resembling short, flat bushes. Adults average 16 millimeters in length, with some individuals only 13 millimeters long. By comparison, the next smallest seahorse, H. bargibanti, averages 24 mm. The smallest known bony fish is the goby Trimmatom nanus, also found in tropical waters and typically just 10 millimeters in length.
The spotted seahorse (Scientific name: Hippocampus kuda) is also known as the common seahorse and Pacific seahorse. The spotted seahorse is strictly a marine species, widely distributed throughout the Pacific Ocean and Indian Ocean, particularly the northwestern, western central, and eastern central areas of the Pacific Ocean. Approximately 23 countries, including China and Australia, have confirmed the native presence of the fish. They are popular ornamental aquarium fish and are distributed globally. [Source: Micheleen Hashikawa, Animal Diversity Web (ADW) /=]
Spotted seahorse typically inhabit shallow inshore areas with an average depth of zero to eight meters (0 to 26 feet) but they have spotted at a maximum depth of 55 meters (180 feet). They can be found in coastal seagrass beds, mangroves, estuaries, coastal bays, lagoons, harbors, sandy sediments in rocky littoral zones, and rivers with brackish waters. They have also been found attached to drifting Sargasssum as far as 20 kilometers from shore. The fish’s lifespan in captivity is typically one to five years. Both wild and cultured Spotted seahorse are susceptible to Costia disease infections, a protozoan parasite
Humans are the primary predators of spotted seahorses because of their economic importance There have few natural predators of adult seahorses due to their unpalatable bony-plated bodies and their ability to avoid predation through camouflage. However, they have been found in the stomachs of loggerhead sea turtles, tunas, and dorados. Skates, rays, and crabs have also been observed to prey on seahorses.
According to Animal Diversity Web: Spotted seahorses are the most valuable species in the traditional Chinese medicine trade (TCM) due to their large size, smooth texture, and pale complexion when dried. Spotted seahorses are very popular among aquatic collectors as a favorite aquarium fish. Spotted seahorses are listed as vulnerable under the World Conservation Union’s International Union for Conservation of Nature (IUCN) Red List and are on the Convention on International Trade in Endangered Species (CITES) Appendix II, which lists species not necessarily threatened with extinction now but that may become so unless trade is closely controlled. .
Population numbers of Spotted seahorse in the wild are unknown but scientists, conservationists, and traders agree that populations have declined by at least 30 percent due to habitat destruction, pollution, bycatch, trades in traditional Chinese medicine, curios, and aquaria There is little legal oversight or regulation on trading, and few countries require permits. Scientists predict further declines in Spotted seahorse population without immediate intervention.
Spotted Seahorse Characteristics and Behavior
Spotted seahorses range in length from seven to 17 centimeters (2.76 to 6.69 inches). Males and females are about the same size but have different shapes. Their weights vary depending on the reproductive stages of both males and females. Spotted seahorse can be distinguished from other seahorse species by the presence of low, rounded bumps instead of the typical spines found along the body. Spotted seahorses have a characteristically thick snout and deep head. They that can move independently. Males can be distinguished from a female by the presence of a brooding pouch on his belly. [Source: Micheleen Hashikawa, Animal Diversity Web (ADW) /=]
Spotted seahorses can have an all black, grainy textured body pattern or a creamy, pale yellow body spotted with large, dark circles. These colors and patterns can be changed temporarily to match their immediate surroundings and act as a camouflage to avoid predators.
Spotted seahorses are ambush predators and thrive only on live, moving food. They are varacious eaters and feed mainly on zooplankton, small crustaceans, and larval fishes. Because they are poor swimmers, they utilize their thick snouts and specialized jaws to suck in their prey.
Spotted Seahorse Mating, Reproduction and Offspring
pot-bellied seahorse The breeding season of the spotted seahorse is year round and breeding may occur every 20 to 28 days. The time to hatching ranges from 20 to 28 days.The first few stages of the mating ritual are repeated, which include changing body color patterns, dancing, and making clicking sounds. This implies they they communicate through visual cues, sounds, and through touch. Seahorses also perceive their environment with these same senses. [Source: Micheleen Hashikawa, Animal Diversity Web (ADW)]
According to Animal Diversity Web: A female may return to lay a new batch of eggs in her partner's pouch the same day that juveniles are released. The maximum reported brood size is 1405, but a brooding pouch may contain anywhere from 20 to 1000 fertilized eggs. Generally only 100 to 200 juvenile seahorses are actually produced per pregnancy, The average length of Spotted seahorse at birth is seven millimeters. In captivity, Spotted seahorse have been observed to reach full maturity in 14 weeks, growing at a rate of .9 to 1.53 millimeters per day.
Like other seahorses, Spotted seahorse has an unusual mode of reproduction where the female provides the eggs but the male carries and cares for the embryos in its brooding pouch While the male carries its brood for 20 to 28 days, the developing larvae are constantly nourshied with a placental-like fluid that is secreted within its pouch. This fluid removes waste products and supplies the fertilized eggs with oxygen and nutrients. As the pregnancy proceeds, the placental fluid gradually changes its chemical content and becomes more similar to the surrounding seawater. This fluid change minimizes the shock newborns experience when they hatch and are released into an environment with higher salt content. These newly released juveniles are fully independent and do not require any parental care once they leave the brooding pouch.
Giant seahorse (Scientific name: Hippocampus ingens) are also known as Pacific seahorses. They are native to the Pacific Ocean and the west coasts of North and South America and oceanic islands in the Pacific. They are found from San Diego, California to Peru as well as on the Cocos, Malpelo, and Galapagos Islands. [Source: Bryan Kelley and Sharmaine Mojica, Animal Diversity Web (ADW) /=]
Giant seahorses can be seen in reefs, protected bays and subtidal seagrass habitats at depths of one to 20 meters (3.28 to 65.62 feet). Their lifespan varies depending on environmental conditions and three to five years in the wild. They are often spotted with their tails wrapped around black coral trees, strands of sea grasses and sea whips, and the branches of gorgonian corals, in order to camouflage themselves from predators. Giant seahorses’s camouflage abilities help them avoid predator yet they have been found in the stomachs of large fishes such dorado, Pacific yellowfin tuna, Pacific bluefin tuna, anglerfish, skates and rays, even sea urchins,
Giant seahorses are popular attractions at public aquariums uses in traditional Chinese medicine. These uses have led to population declines and heightened concerns regarding conservation.. Habitat destruction and overfishing are the biggest threats to the giant seahorse. Their populations have declined by 50 percent from 2007-2012. Each year, thousands seahorses are accidentally caught by shrimp trawlers. To protect them some conservation actions have been implemented in some countries. Mexico, for example, has listed giant seahorses as a species subject to special protection, and fishermen are not allowed to intentionally catch these animals. In Panama, the species is listed as protected in a mandate managing coral reefs. The IUCN Red List categorizes them as vulnerable. There placed in CITES Appendix II, which lists species not necessarily threatened with extinction now but that may become so unless trade is closely controlled. /=\
Giant Seahorse Characteristics, Feeding and Behavior
Adult giant seahorses range in length from 13 to 30 centimeters (5 to 12 inches). Sexual Dimorphism (differences between males and females) occurs: The sexes are colored and patterned differently; males and females have different shapes; and females typically have a dark patch located ventrally on the anal fin, while males have a slight keel on the chest and a brooding pouch, located under the tail. [Source: Bryan Kelley and Sharmaine Mojica, Animal Diversity Web (ADW) /=]
According to Animal Diversity Web: Populations display a wide array of body colors, as these animals can change their body color, depending on their environment. Body colors include maroon, yellow, and muddled brownish-green. The darkish body may have small dark and white spots and longitudinal streaks along the length of the body. The neck is curved at a right angle to the rest of the body. Atop the head is a bony structure called a coronet, which has five points, and an elongate snout extends from the front of the face.
Giant seahorses are nocturnal (active at night). and usually observed as solitary creatures, anchored around eelgrass by their prehensile tails. Their diet consists mainly of small crustaceans and zooplankton, favoring brine shrimp and mysids — small, shrimp-like crustaceans that are high in protein and lipids. Juveniles probably consume phytoplankton.
Giant Seahorses Mating, Reproduction and Offspring
Giant seahorses are ovoviviparous (eggs are hatched within the body of the individual that gives birth), in the cases of seahorses, the male. are iteroparous (offspring are produced in groups). They engage in year-round breeding and They engage in internal reproduction in which sperm from the male fertilizes the egg within the female. Individuals may mate again immediately after a clutch has been born (every 14-15 days). [Source: Bryan Kelley and Sharmaine Mojica, Animal Diversity Web (ADW) /=]
Females and males reach sexual or reproductive maturity at three to six months. The number of offspring ranges from 50 to 2000. The time to hatching ranges from 14 to 45 days. Parental care is provided by males. Males retain eggs in their brood pouches until they hatch. After young are released, they are independent and there is no further investment from either parent.
According to Animal Diversity: Although these seahorses are not known to form lifelong pair bonds with mates as some species do, they still exhibit elaborate mating rituals. Males may be aggressive toward each other in competition for females, head butting and tail wrestling each other. Mating pairs will meet and rub their heads together, then intertwine their tails together and around a blade of sea grass or similar structure, performing a mating "dance" by bobbing up and down together. This behavior lasts for three days. Finally, a male will display his empty breeding pouch, which the female will fill with eggs using her ovipositor. After mating and transfer of her eggs to a male, a female typically will not mate again until he has given birth.
Reproductive activity has been observed in giant seahorses as early as three months of age in captivity; at this age, clutch sizes tend to be quite small and males are often unsuccessful at courtship displays. Successful reproductive attempts seem to begin around six months of age. A particular breeding season has not been identified for these seahorses, though it is thought that they may breed year round. Young are typically released during full moon high tides, providing optimum levels of resources to juveniles.
Pre-birth protection is provided by the male. Smooth, pear-shaped, yellowish eggs are deposited by a female into a male's breeding pouch, where they are fertilized. The eggs embed in the lining of the brooding pouch and are supplied with oxygen by surrounding capillaries. They develop for 14-15 days, depending on water temperature. After release, typically during full moon high tides, pelagic (living in the open ocean, far from land) young are independent. Juveniles are approximately nine millimeters in length during the first two months of their lives. As growth proceeds, individuals become mature at approximately 5.4 centimeters in length.
Sea dragons are related to sea horses but have several difference — namely the way they move and use their tail. There are just two species — leafy and weedy, named for their form of camouflage — and both live in the temperate waters off Australia. Like seahorses they are an ambush predators that feeds by sucking small aquatic organisms rapidly into their mouth
The leafy seadragon is found only off of Western and Southern Australia. Living mainly in kelp forest off places like the Fleurieu Peninsula, near Adelaide, it can grow over 35 centimeters long and grows bony prongs from its spine, ribs and head that trail thin ribbons of camouflage. Little is known about it. It has been studied by marine biologist Greg Rouse, who has collected its DNA and found out that what was thought to be two species is actually one found over a large range. You can point one out to someone and they won’t see it, Rouse said, “I’m sure I swim over them all the time.” [Source: National Geographic]
Sea dragons have no teeth; they feed by way of suction. Their pipe-like terminal mouth has an intricate system of bones pulled by muscles to create a strong suction force that is directed at food. Their prey include mysid shrimp, sea lice, and larval fish. They sense using touch and chemicals usually detected with smell. Within the Syngnathidae family seahorses are Phycodurus and seadragons are Phyllopteryx.
Sea dragons are solitary animals that have no known predators. They are not sessile, but they are not very good swimmers, either. This is because their bodies are surrounded by protective dermal plates, which inhibit their mobility. Also, they lack a caudal fin, and therefore must rely on their ventral and dorsal fins for swimming. Because they are poor swimmers, each year a number of individuals are found washed ashore on the beaches of southern Australia. /=\
Weedy Sea Dragon
Weedy sea dragons (Scientific name: Phyllopteryx taeniolatus) are also known as Common seadragons, and Lucas' sea-dragon. They are endemic to the waters off of the southern coast of Australia, with Individuals of this species sighted off the eastern coast of Australia in New South Wales, as far north as Port Stephens; along the southern coast; and up around the western coast of Australia as far north as Geraldton, West Australia. [Source: Anna Frostic, Animal Diversity Web (ADW) /=]
Weedy sea dragon can be found in rocky reefs, sea weed beds, sea grass meadows, and kelp gardens. In all of these areas, their leafy appendages provide protection by serving as camouflage against the sea weed. They are typically found at depths of 10 to 50 meters (33 to 164 feet) in waters that must be between 12 and 23 degrees Celsius (53 to 73 degrees F)
The weedy sea dragons can reach 45 centimeters in length and has a narrow body with a long, tubular snout. According to Animal Diversity Web: It has two spines above its eye, one spine in front of the eye, and a varying number of leafy appendages, either paired or single, along its body. These purple appendages have a black border, and provide the fish camouflage in its habitat because they resemble floating seaweed. The bodies of these fish are usually red with yellow spots and seven purplish blue stripes near the head. Weedy sea dragons are not sexually dimorphic and have no subspecies, but do have a close relative: Phycodurus eques, the leafy sea dragon. The leafy sea dragon is found in the same geographic range, and differs in appearance only because it has many more appendages.
While it is not known at what age sea dragons reach sexual maturity, their reproductive strategies are well documented. Like their relatives the sea horses, the male sea dragons brood the eggs. When a male is ready to receive the eggs, which he indicates by wrinkling the lower half of his tail, the female deposits about 250 ruby colored eggs onto his brood patch. The brood patch is made of tiny cups of blood-rich tissue, and each cup holds and nourishes one egg. After eight weeks, the eggs hatch over a period of a couple days. After hatching, the young sea dragons spend two or three days in the yolk sac of the egg, where they continue to be nourished. After the young leave the yolk sac, they feed on copepods and rotifers, although only 60-120 of them will survive, while the others fall prey to sea anemones. The season of breeding is August through March, and during this time the males brood two batches of eggs. The young receive no parental care after they hatch because they are released into the external environment.
Weedy Sea Dragon, Humans and Fish Farming
Weedy sea dragon have been used in Asian medicines and one reason why divers brave great white sharka to scuba diving off the coast of southern Australia, Weedy sea dragons are threatened by aquarium collectors and Oriental herbalists, who can sell their dried and powdered bodies for up to $200/gram. They are also killed by pollution and fertilizer run-off in their shallow, coastal habitats. Because of these threats, weedy sea dragons are a legally protected species in both New South Wales and Tasmania. On the IUCN ) Red List they are categorized as near threatened.. On CITES they have no special status
Juliet Eilperin wrote in the Washington Post: Aquarists have made some breakthroughs with The Aquarium of the Pacific in Long Beach, Calif., became the world’s first to breed weedy sea dragons in 2001, from a progenitor named “Big Daddy,” but it only repeated that feat once, in 2003. Perry Hampton, the aquarium’s vice president of husbandry, said his team has mimicked the sea dragons’ natural environment through water temperature and light exposure, but they can’t force the animals to mate. Scripps professor Greg Rouse received a $300,000 grant to launch the first-of-its-kind sea-dragon breeding pilot program with the Birch Aquarium. [Source: Juliet Eilperin, Washington Post April 15, 2012]
Pipefish (Syngnathinae) belong to the same family (Syngnathidae) as seahorses and seadragons.Pipefish look like straight-bodied seahorses with tiny mouths. The name is derived from the peculiar form of the snout, which is like a long tube, ending in a narrow and small mouth which opens upwards and is toothless. The body and tail are long, thin, and snake-like. They each have a highly modified skeleton formed into armored plating. This dermal skeleton has several longitudinal ridges, so a vertical section through the body looks angular, not round or oval as in the majority of other fishes. The gill openings are extremely small and placed near the upper posterior angle of the gill cover. [Source: Wikipedia]
Pipefish are generally weak swimmers in open water, moving slowly by means of rapid movements of the dorsal fin. The dorsal fin, for some species, is only means of locomotion. The ventral fins are consistently absent, and the other fins may or may not be developed. Some species of pipefish have prehensile tails, as in seahorses. The majority of pipefishes have some form of a caudal fin (unlike seahorses), which can be used for locomotion. Some species of pipefish have more developed caudal fins, such as the group collectively known as flagtail pipefish, which are quite strong swimmers.
Most pipefishes are marine dwellers; only a few are freshwater species. They are abundant on coasts of the tropical and temperate zones. Most species of pipefish are usually 35–40 centimeters (14–15.5 inches) in length and generally inhabit sheltered areas in coral reefs or seagrass beds. Male pipefish, like male sea horses, get “pregnant.” When the male and female mate, the female attaches her eggs to the underside of the male. The skin of the male under the eggs swells and produces a pocket that holds the eggs until they hatch.
Image Sources: Wikimedia Commons; YouTube, Animal Diversity Web, NOAA
Text Sources: Animal Diversity Web (ADW) animaldiversity.org; National Oceanic and Atmospheric Administration (NOAA) noaa.gov; Wikipedia, National Geographic, Live Science, BBC, Smithsonian, New York Times, Washington Post, Los Angeles Times, The New Yorker, Reuters, Associated Press, Lonely Planet Guides and various books and other publications.
Last Updated March 2023