Seahorses are fascinating sea creatures native to saltwater environments from the tropics to temperate zones. They are called “seahorses” because of their horse-like heads –even their scientific name is based on the Greek word for horse (Hippocampus). The fins on the sides of their heads can beat up to 50 times a second, and their tails are prehensile (they can be used to hold onto or grasp objects) like a monkey’s. From a scientific perspective, seahorses are classified as fish. Of the possible 50 species of seahorses known to science, at least six are native to the United States and Outlying Territories (American Samoa; Baker, Howland and Jarvis Islands; Guam; Johnston Atoll; Kingman Reef; Midway Islands; Navassa Island; Northern Mariana Islands; Palmyra Atoll; Puerto Rico; U.S. Virgin Islands; Wake Islands).

Seahorses are relatively immobile and they live in habitats such as mangrove forests and sea grass beds that provide food (usually brine shrimp) and shelter (including camouflage against predators). Seahorses spend a lot of time in one area by wrapping their tails around underwater plants or coral. In some species, male and female seahorses form monogamous breeding pairs – that is, they mate for life.

Perhaps one of the most fascinating facts about seahorses is that males give birth to the young! After the female deposits her eggs in the male’s brood pouch, he fertilizes the eggs and anchors himself to a solid surface to await the birth – sometimes for up to several weeks. The size of the wild population is unknown.

Several characteristics make seahorses naturally vulnerable to extinction. Although they are native to the waters off more than 130 countries, seahorses are patchy in distribution. Seahorses tend to have low birth rates, with lengthy parental care.  In addition, the waters they live in are often exploited by people – such as for fishing or urban development – which degrades and destroys their habitat. Seahorses themselves are intentionally harvested by people for the curio and aquarium trade and for traditional medicines, both domestically and internationally. There is some international trade in U.S.-native seahorses, but most trade (worldwide and entering the United States) comes from Asia.

Laws & Regulations

Our native seahorses have varying levels of rarity and protection throughout the United States and Outlying Territories (listed above), and laws vary from State to State. There are currently no seahorse species listed under the Endangered Species Act, although dwarf seahorse is being evaluated for possible listing by the National Marine Fisheries Service (NMFS).

In addition, the genus Hippocampus was listed in Appendix II of the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES) as of 2004, based on a proposal put forward by the United States. As part of the listing, CITES Parties agreed to a voluntary minimum size limit for wild-collected seahorses , which the United States adheres to. This minimum size limit is designed to discourage people from harvesting immature seahorses that have not had a chance to reproduce and contribute to the population. To read more on this CITES recommendation, click here .

CITES regulations also recognize that international trade in captive-bred seahorses , rather than wild, reduces the collection pressure on wild populations.

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